PALAEOBOTANY  . In the See also:

• PRESENT

present See also:

• ARTICLE (from Lat. articulus, a joint)

article the subject of See also:

• VEGETABLE

vegetable palaeontology is treated from a botanical point of view . The See also:

• SCIENCE (Lat. scientia, from scire; to learn, know)

science of See also:

• BOTANY (from Gr. l3or6v17, plant; ,66vicety, to graze)

botany is concerned with the vegetable See also:

• KINGDOM

kingdom as a whole, and not merely with the See also:

• FLORA

flora now living . The remains of the See also:

• PLANTS

plants of former periods, which have come down to us in the fossilized See also:

• STATE
• STATE, GREAT OFFICERS OF

state, are almost always fragmentary, and often imperfectly preserved; but their investigation is of the utmost importance to the botanist, as affording the only See also:

• DIRECT

direct See also:

• EVIDENCE (Lat. evidentia, evideri, to appear clearly)

evidence of the past See also:

• HISTORY

history of vegetable organisms . Since the publication of the Origin of See also:

• SPECIES

Species the See also:

• GENERAL
• GENERAL (Lat. generalis, of or relating to a genus, kind or class)

general See also:

• ACCEPTANCE (Lat. acceptare, frequentative form of accipere, to receive)

acceptance of the See also:

• DOCTRINE

doctrine of See also:

• EVOLUTION

evolution has given a vastly increased significance to palaeontological data . The determination of the course of descent has now become the ultimate problem for the systematist: this is an See also:

• HISTORICAL

historical question, and the historical documents available are the remains of the See also:

• ANCIENT
• ANCIENT (also spelt ANTIENT; derived, through the Fr. ancien, old, from the late Lat. antianum, from ante, before)

ancient organisms preserved in the rocks . The palaeobotanist thus endeavours to trace the history of plants in the past, with the See also:

• HOPE, ANTHONY
• HOPE, THOMAS (c. 1770-1831)

hope of throwing See also:

• LIGHT

light on their natural See also:

• AFFINITIES

affinities and on the origin of the various See also:

• GROUPS
• GROUPS, THEORY

groups . His investigations must embrace not only the See also:

• COMPARATIVE

comparative See also:

• MORPHOLOGY, (Gr. yopdsil, form)

morphology and See also:

• ANATOMY
• ANATOMY (Gr. avaroyil, from ava-silo c', to cut up)

anatomy of fossil plants, but also their See also:

• DISTRIBUTION (Lat. distribuere, to deal out)

distribution over the See also:

• EARTH
• EARTH (a word common to Teutonic languages, cf. Ger. Erde, Dutch aarde, Swed. and Dan. jord; outside Teutonic it appears only in the Gr. 'pq'e, on the ground; it has been connected by some etymologists with the Aryan root ar-, to plough, which is seen in
• EARTH, FIGURE OF
• EARTH, FIGURE OF THE

earth's See also:

• SURFACE

surface at different periods—a See also:

• PART

part of the subject which, besides its direct biological See also:

• INTEREST

interest, has obvious See also:

• BEARINGS

bearings on ancient climatology and See also:

• GEOGRAPHY (Gr. yil, earth, and ypiickty, to write)

geography . Preservation.—Before considering the results of palaeobotanical See also:

• RESEARCH (O. Fr. recerche, from recercher, re- and cercer, mod. chercher, to search; Late Lat. circare, to go round in a circle, to explore)

research, some See also:

• ACCOUNT
• ACCOUNT (through O. Fr. acont, Late Lat. comptum, cornputare, to calculate)

account must be given of the way in which the evidence is presented, or, in other words, of the modes of preservation of vegetable remains . These fall under two See also:

• MAIN (from the Aryan root which appears in " may " and " might," and Lat. magnus, great)
• MAIN (Lat. Moenus)

main heads . On the one See also:

• HAND
• HAND (a word common to Teutonic languages; cf. Ger. Hand, Goth. handus)
• HAND, FERDINAND GOTTHELF (1786-185r)

hand, there is the mode of preservation which gives rise to casts, moulds and generally impressions, exhibiting the superficial features of the specimen . The See also:

• GREAT

great See also:

• MAJORITY (Fr. majorite; Med. Lat. majoritas; Lat. major, greater)

majority of vegetable fossils are of this See also:

• KIND (O. E. ge-cynde, from the same root as is seen in " kin," supra)

kind, and the See also:

• TERM

term incrustation is used as a general term to See also:

• COVER (from the Fr. convert, from couvrir, to cover, Lat. cooperire)

cover all such methods of fossilization; On the other hand, there are specimens in which the tissues of the plant have been permeated by some See also:

• MINERAL

mineral in See also:

• SOLUTION (from Lat. solvere, to loosen, dissolve)

solution, which, subsequently setting hard, has fixed and preserved the See also:

• INTERNAL

internal structure, often with astonishing perfection of detail .

This second method of fossilization is termed petrifaction . In the See also:

• CASE
• CASE, JOHN (d. 1600)

case of incrustation the 'whole substance of the fossilized specimen—e.g., a See also:

• STEM (O. Eng. staefn, stemn, cf. Du. stain, Ger. Stamm, &c., probably related to " staff ")

stem of Sigillaria—may be replaced by mineral See also:

• MATTER

matter, such as See also:

• SANDSTONE

sandstone or shale, giving a See also:

• CAST (from the verb meaning " to throw "; the word is Scand. in origin, cf. Dan. kaste, and Swed. kasta; " cast " in Middle Eng. took the place of the A.S. weor pan, cf. Ger. werf en)

cast of the whole, on the See also:

• OUTER

outer surface of which the See also:

• EXTERNAL

external markings, such as the bases of leaves and the scars See also:

• LEFT

left by their fall, are visible in their natural See also:

• FORM (Lat. forma)

form . Usually the See also:

• ORIGINAL

original organic substance remains as a thin carbonaceous layer forming the surface of the cast, but some-times it has entirely disappeared . The surrounding See also:

• MATRIX

matrix will of course show the See also:

• MOULD

mould of the cast, with its elevations and depressions reversed . In the case of thin, See also:

• FLAT (a modification of O. Eng. flet, an obsolete word of Teutonic origin, meaning the ground beneath the feet)

flat See also:

• ORGANS

organs such as leaves, the whole See also:

• ORGAN

organ may be spread out in the See also:

• PLANE

plane of stratification, leaving its impress on the overlying and underlying layers . Here there has not necessarily been any replacement of organic by inorganic material; the whole See also:

• LEAF (O. Eng. leaf, cf. Dutch loof, Ger. Laub, Swed. lof, &c.; possibly to be referred to the root seen in Gr. Ma-eta, to peel, strip)

leaf, for example, may remain, though reduced to a carbonaceous film . In such carbonaceous impression not only are the form and markings, such as venation, perfectly pre-served, but something of the actual structure may remain . The cuticularized epidermis, especially, is often thus preserved, and may be removed by the use of appropriate reagents and examined microscopically . If sporangia and spores are present they also may persist in a perfectly recognizable form, and in fact much of our knowledge of the fructification of fossil Ferns and similar plants has been derived from specimens of this kind . In many cases internal casts have been formed, some large cavity, such as a fistulae See also:

• PITH (O.E. pitca, cognate with Du. pit, kernel of a nut)

pith, having become filled with mineral substance, which has taken the impress of the surrounding structures, such as the See also:

• WOOD, ANTHONY A2 (1632-1695)
• WOOD, JOHN GEORGE (1827—1889)
• WOOD, MRS HENRY [ELLEN] (1814—1887)
• WOOD, SEARLES VALENTINE (1798—188o)

wood . The See also:

• COMMON

common casts of Calamites are of this nature, representing the form of the hollow medulla, and bearing on their surface the See also:

• PRINT

print of the nodal constrictions and of the ridges and furrows on the inner surface of the wood . The whole organic sub-stance may have been removed, or may persist merely as a thin carbonaceous layer .

Mistakes have often arisen from confusing these medullary casts with those of the stem as a whole . Although some See also:

• INFORMATION (from Lat. informare, to give shape or form to, to represent, describe)

information as to See also:

• MINUTE
• MINUTE (Lat. minutes, small; minuere, to make less)

minute structure may often be gleaned from the carbonaceous coating of impressions, the fossils preserved by petrifaction are the main source of our knowledge of the structural characters of ancient plants . The chemical bodies which have played the most important part as agents of petrifaction are silicic See also:

• ACID (from the Lat. root ac-, sharp; acere, to be sour)

acid and See also:

• CALCIUM [symbol Ca, atomic weight 40.0 (o= x6)]

calcium carbonate, though other substances, such as See also:

• MAGNESIUM [symbol Mg, atomic weight 24.32 (0 = 16)]

magnesium carbonate, calcium sulphate and ferric See also:

• OXIDE

oxide have also been concerned, either as the See also:

• CHIEF (from Fr. chef, head, Lat. caput)

chief constituents ofpetrifac-tions, or mixed with other bodies . A large number of the most important remains of plants with structure preserved are silicious; this is the case, for example, with the famous See also:

• FRENCH
• FRENCH, DANIEL CHESTER (1850– )
• FRENCH, NICHOLAS (1604-1678)

French Permo-Carboniferous fossils of St See also:

• ETIENNE, CHARLES GUILLAUME (1778-1845)

Etienne, See also:

• AUTUN

Autun, &c., which in the hands of See also:

• BRONGNIART, ADOLPHE THEODORE (1801–1876)
• BRONGNIART, ALEXANDRE (1770-1847)

Brongniart, Renault and others have yielded such brilliant scientific results . At a more See also:

• RECENT

recent See also:

• HORIZON (Gr. 6pfTwv, dividing)

horizon, the silicified specimens of the Mesozoic See also:

• GYMNOSPERMS

Gymnosperms from Great See also:

• BRITAIN (Gr. Hperavuml vi7vot, Bperravia; Lat. Britannia, rarely Britannia)

Britain, See also:

• FRANCE
• FRANCE, ANATOLE (1844– )

France, and especially See also:

• NORTH
• NORTH, BARONS
• NORTH, MARIANNE (1830—1890)
• NORTH, ROGER (1653-1734)
• NORTH, SIR THOMAS (1535?-16o1?)

North See also:

• AMERICA

America, are no less important . Calcified specimens are especially characteristic of the See also:

• BRITISH

British Carboniferous formation; their preservation is equally perfect with that of the silicified fossils, and their investigation by See also:

• WITHAM

Witham, See also:

• BINNEY, EDWARD WILLIAM (1812-1881)
• BINNEY, HORACE (1780-1875)
• BINNEY, THOMAS (1798-1874)

Binney, See also:

• WILLIAMSON, ALEXANDER WILLIAM (1824–1904)
• WILLIAMSON, SIR JOSEPH (1633–1701)
• WILLIAMSON, WILLIAM CRAWFORD (18r6–1895)

Williamson and others has proved no less fertile . In the See also:

• COAL

Coal See also:

• MEASURES

Measures of See also:

• ENGLAND
• ENGLAND, THE CHURCH OF

England and of certain See also:

• GERMAN
• GERMAN, DUTCH AND SCANDINAVIAN

German and See also:

• AUSTRIAN

Austrian districts (e.g . Langendreer in See also:

• WESTPHALIA (Ger. Westfalen)
• WESTPHALIA, TREATY OF

Westphalia; See also:

• OSTRAU

Ostrau in See also:

• MORAVIA (Ger., Ma/wen; Czech, Morava)

Moravia), calcareous nodules, crowded with vegetable fragments of every kind, occur in certain mines embedded in the substance of the coal and representing its raw material in a petrified See also:

• CONDITION (Lat. condicio, from condicere, to agree upon, arrange; not connected with conditio, from condere, conditum, to put together)

condition . Even the most delicate tissues, such as cambium and phloem, the endosperm of seeds, or the formative See also:

• TISSUE (Fr. tissu, tissue, participle of tisser, Lat. texere, to weave)

tissue of the growing-point, are frequently preserved See also:

• CELL (from Lat. cella, probably from an Indo-European kal —seen in Lat. celare, to hide; another suggestion connects the word with Lat. cera, wax, taking the original meaning to refer to the honeycomb)

cell for cell, both in calcareous and silicious material . As a See also:

• RULE

rule, the petrified remains, all-important for the See also:

• REVELATION, BOOK OF

revelation of structure, are fragmentary, and give little See also:

• IDEA (Gr. Ibia, connected with i&eiv, to see; cf. Lat. species from specere, to look at)

idea of the See also:

• HABIT (through the French from Lat. habitus, from habere, to have, hold, or, in a reflective sense, to be in a certain condition; in many of the English senses the French use habitude, not habit)

habit or external characters of the plants from which they were derived . Hence they must be brought into relation with the specimens preserved as casts or impressions, in See also:

• ORDER
• ORDER (through Fr. ordre, for earlier ordene, from Lat. ordo, ordinis, rank, service, arrangement; the ultimate source is generally taken to be the root seen in Lat. oriri, rise, arise, begin; cf. " origin ")
• ORDER, HOLY

order to gain a better conception of the plant as a whole . This is often a difficult task, and generally the fragmentary nature of practically all vegetable fossils is the chief hindrance to their investigation .

Owing to this, it has become the common practice of palaeobotanists to give distinct generic names to detached parts of plants which may even have belonged to one and the same species . Thus the roots of Sigillaria are called Stigmaria, detached leaves Sigillariophyllunz, and the fructifications Sigillariostrobus; the name Sigillaria applies to the stem, which, however, when old and partly decorticated has been called Syringodendron, while its woody See also:

• CYLINDER (Gr. KvAwSpos, from KvXivaety, to roll)

cylinder has often been described under the name Diploxylon . This naming of portions of plants, however objectionable, is often not to be avoided; for detached organs constantly have to be de-scribed See also:

• LONG, GEORGE (1800-1879)
• LONG, JOHN DAVIS (1838– )

long before their relation to other parts is established—which, indeed, may never be accomplished . For example, the form and structure of Stigmaria have long been well known; but it is seldom possible to determine whether a given Stigmaria belonged to Sigillaria, Lepidodendron or some other genus . The correct piecing together of the fragmentary remains is one of the first problems of the palaeobotanist, and the See also:

• GRADUAL (Med. Lat. gradualis, of or belonging to steps or degrees; gradus, step)

gradual disappearance of superfluous names affords a See also:

• FAIR

fair measure of the progress of his science . The recent advance of fossil botany has depended in a very great degree on the study of petrified specimens with their structure preserved; so far, at least, as the older strata are concerned, it is, as a rule, only with the help of specimens showing structure that any safe conclusions as to the affinities of fossil plants can be arrived at . The subject of coal (q.v.) is treated elsewhere . Here it need only be said that the masses of vegetable substance, more or less carbonized and chemically altered, of which coal is composed, frequently contain cells and fragments of tissue in a condition recognizable under the See also:

• MICROSCOPE (Gr. µucp6s, small, asenreiv, to %view)

microscope, as for example spores (some-times present in great quantities), elements of the wood, See also:

• FIBRES
• FIBRES (or FIBERS, in American spelling; from Lat. fibra, apparently connected either with filum, thread, or findere, to split)

fibres of the bark, &c . These remnants, however, though interesting as revealing something of the See also:

• SOURCES

sources of coal, are too fragmentary and imperfect to be of any botanical importance . In See also:

• LIGNITE (Lat. lignum, wood)

lignite, on the other hand, the organized structure is sometimes excellently preserved . In the See also:

• WEALDEN

Wealden of See also:

• BELGIUM
• BELGIUM (Fr. Belgique; Flem. Belgic)

Belgium„ for example, specimens of Ferns and Coniferae occur, in the form of lignite, which can be sectioned, like recent plants, with a See also:

• RAZOR (O.F. razor, mod. rasoir, from racer, to scrape, rase, Late Lat. rasare, frequentative of radere, to scrape)

razor, and exhibit an almost unaltered structure . I.—PALAEOZOIC The present See also:

• SECTION
• SECTION (Lat. sectio, cutting, secare, to cut)

section is concerned with the botany of the Palaeozoic See also:

• AGE (Fr. age, through late Lat. aetaticum, from aetas)

age, from the See also:

• OLDEST

oldest rocks in which vegetable remains have been found up to the See also:

• CLOSE
• CLOSE (from Lat. clausum, shut)
• CLOSE, MAXWELL HENRY (1822-1903)

close of the See also:

• PERMIAN

Permian See also:

• PERIOD
• PERIOD (Gr. irepioSos, a going or way round, circuit, aepi, round, and &Sis, way, road)

period .

The Glossopteris flora of See also:

• INDIA
• INDIA, FRENCH

India and the See also:

• SOUTHERN

southern hemisphere, the age of which has been disputed, but is now regarded as for the most part Permo-Carboniferous, is, however, dealt with in the succeeding section, in connexion with the Mesozoic floras . The various groups of plants represented in the Palaeozoic rocks will first be considered in systematic order, after which some account will be given of the See also:

• SUCCESSION (Lat. successio, from succedere, to follow after)

succession and distribution of the various floras during the period . In dealing with the plants of such remote epochs, the relative importance of the various groups, so far as they are known to us, is naturally very different from that which they assume at the present See also:

• DAY (O. Eng. dreg, Ger. Tag; according to the New English Dictionary, " in no way related to the Lat. dies")
• DAY, JOHN (1574-1640?)
• DAY, THOMAS (1748-1789)

day . There is no evidence that the Angiospermous flowering plants, now the dominant class, existed during the Palaeozoic period; they do not appear till far on in the Mesozoic See also:

• EPOCH (Gr. E7roxij, holding in suspense, a pause, from E1rxav, to hold up, to stop)

epoch, and their earlier history is as yet entirely unknown . On the other hand, See also:

• FERN (from O. Eng. fearn, a word common to Teutonic languages, cf. Dutch varen, and Ger. Farn; the Indo-European root, seen in the Sanskrit parna, a feather, shows the primary meaning; cf. Gr. rmep6 , feather, rTepis, fern)

fern-like See also:

• SEED (from the root seen in Lat. serere, to sow)

seed-plants, known as Pteridosperms, and Gymnosperms belonging almost entirely to families now See also:

• EXTINCT

extinct, were abundant, while the See also:

• PTERIDOPHYTA (Gr. 1ripts, fern, and d,vrde plant)

Pteridophyta attained a development exceeding anything that they can now show . Among the See also:

• LOWER

lower classes of plants we have scarcely any know-ledge of Palaeozoic See also:

• BRYOPHYTA

Bryophyta; See also:

• FUNGI (p1. of Lat. fungus, a mushroom)

Fungi were probably abundant, but their remains give us little information; while, even among the See also:

• ALGAE

Algae, which are better represented, well characterized specimens are scanty . With few exceptions, the remains of Palaeozoic Algae are of comparatively little botanical interest . A vast number of " species " AkBe have been described, but, as has been said, " by far the greater number of the supposed fossil Algae have no claim to be regarded as See also:

• AUTHENTIC (from Gr. aOO 'rns, one who does a thing himself)

authentic records of this class of Thallophytes " (See also:

• SEWARD, ANNA (1747-1809)
• SEWARD, WILLIAM HENRY (180r-1872)

Seward, 1898) . The investigations of Nathorst, See also:

• WILLIAM
• WILLIAM (1143-1214)
• WILLIAM (1227-1256)
• WILLIAM (1J33-1584)
• WILLIAM (A.S. Wilhelm, O. Norse Vilhidlmr; O. H. Ger. Willahelm, Willahalm, M. H. Ger. Willehelm, Willehalm, Mod.Ger. Wilhelm; Du. Willem; O. Fr. Villalme, Mod. Fr. Guillaume; from " will," Goth. vilja, and " helm," Goth. hilms, Old Norse hidlmr, meaning
• WILLIAM (c. 1130-C. 1190)
• WILLIAM, 13TH

William-son and others have shown that a very large proportion of the casts and impressions attributed to Algae had in all See also:

• PROBABILITY (Lat. probabilis, probable or credible)

probability a totally different origin . Some represent the tracks or burrows of See also:

• WORMS

worms, crustaceans or other animals; others, the course of rills of See also:

• WATER

water on a sandy or muddy See also:

• SHORE

shore; others, again, the marks left on the bottom by bodies drifted along by the waves . In cases of doubt, evidence may be obtained from traces of organic structure, from the presence of carbonaceous-matter, or, as Zeiller has pointed out, by the remains of animals such as Bryozoa being attached to the cast, showing that it represents a solid See also:

• BODY

body and not a See also:

• MERE
• MERE, ADALBERT (1838-1909)

mere cavity or furrow., Evidence from traces of organization is alone conclusive; the' presence of carbonaceous matter, though a useful indication, may be deceptive, for the organic substance may have been derived from other sources than the body which left the impression . The mere external form of the supposed Algae is rarely so characteristic as to afford satisfactory evidence of their nature .

Some of the better-attested examples, among which are a few of considerable interest, may now be considered . Of Cyanophyceae, as we should expect, the Palaeozoic remains ,are very doubtful . Gloioconis, found by Renault in a coprolite of Permian age, was regarded by him as a Cyanophycean allied to Gloeocapsa ; this may be so, but the See also:

• ARGUMENT

argument See also:

• DRAWN

drawn from the See also:

• ABSENCE (Lat. absentia)

absence of nuclei, See also:

• CON

con- ` sidering the extreme rarity of recognizable nuclei even in the best preserved fossil tissues, can hardly be taken seriously . Girvanella, found in See also:

• CAMBRIAN

Cambrian, Ordovician and See also:

• SILURIAN

Silurian rocks, as well as in later deposits, appears to have played a part in the origination of oolitic See also:

• ROCK
• ROCK (O.Fr. rake, Sp. rota, Ital. rocca; possibly from a Lat. form rupica, from rupes, rock)
• ROCK, DANIEL (1799–187t)

rock-structure . It consists of minute interwoven tubular filaments, and has been variously interpreted as possibly representing the sheaths of a Cyanophycean Alga, and as constituting a Siphoneous thallus of the type of the Codieae . - The non-cellular order Siphoneae is fairly well represented in Palaeozoic strata, especially by calcareous verticillate forms referable to the See also:

• FAMILY

family Dasycladeae; the See also:

• SEPARATE

separate tubular See also:

• JOINTS

joints of the articulated thallus, bearing the prints of the whorled branches, are sometimes cylindrical (Arthroporella, Vermiporella, &c.), sometimes See also:

• OVAL (Lat. ovum, egg)

oval (Sycidium) or spherical (Cyclocrinus) . These forms, and others like them, go back to the Silurian and Ordovician; while Gyroporella, from the Permian, is another fairly characteristic Siphoneous type . There can be no doubt that the verticillate Siphoneae, a See also:

• GROUP

group much isolated among recent organisms, are among the most ancient families of plants . The gigantic Nematophycus, to be described below, has been regarded as having Siphoneous affinities . Little trace of - Confervaceae has been found; Confervites chantransioides, apparently consisting of branched cellular filaments, may perhaps represent a Cambrian Confervoid . Cladiscothallus, from the See also:

• CALM

Calm of See also:

• RUSSIA
• RUSSIA (Rossiya)

Russia, in which the filaments are See also:

• UNITED

united to form hemispherical or globular tufts, has been compared by Renault to a Chaetophora . This is one of the somewhat doubtful Algae occurring in boghead coal or torbanite, a carbonaceous rock the nature of which has been much disputed, in the See also:

• LAW
• LAW (0. Eng. lagu, M. Eng. lawe; from an old Teutonic root lag, " lie," what lies fixed or evenly; cf. Lat. lex, Fr. loi)
• LAW, JOHN (1671—1729)
• LAW, WILLIAM (1686-1761)

law courts as well as in scientific literature .

The boghead of See also:

• SCOTLAND
• SCOTLAND, CHURCH OF
• SCOTLAND, EPISCOPAL CHURCH OF

Scotland, Autun and New See also:

• SOUTH
• SOUTH, ROBERT (1634–1716)

South See also:

• WALES (Cymru, Gwalia, Cambria)

Wales is regarded by Renault and See also:

• BERTRAND, HENRI GRATIEN, COMTE (1773-1844)

Bertrand as mainly composed of gelatinous Algae (See also:

• PILE

Pile and Reinschia), having a hollow, saccate thallus formed of a single layer of cells . It may appear surprising that a body containing 65 % of See also:

• CARBON (symbol C, atomic weight 12)

carbon should be so largely made up of gelatinous Algae in a comparatively little altered condition, but the material is See also:

• RICH, BARNABE (c. 1540-1617)
• RICH, CLAUDIUS JAMES (1787-1821)
• RICH, JOHN (1692-1761)
• RICH, PENELOPE, LADY (c. 1562–1607)
• RICH, RICHARD, 1ST BARON RICH (1490?-1567)

rich in See also:

• BITUMEN

bitumen, which seems to have replaced the water- contained in the organisms when alive . It has recently been stated, however, that the supposed Algae are in reality the megaspores of Vascular Cryptogams . Scarcely anything is known of Palaeozoic Florideae; Solenopore, ranging from the Ordovician to the See also:

• JURASSIC

Jurassic, resembles, 'in the structure of its thallus, with definite zones of growth, Corallinaceae such as Lithothamnion, and may probably be of the same nature . A branched 'filamentous organism from the Lower Carboniferous of Scotland, described by Kidston under the name of Bythotrephis worstoniensis, shows some remains of cellular structure, and may probably be a true Alga, resembling some of the filamentous Florideae in habit . Apart from the multitude of supposed fossil Algae described as " Fucoids " but usually not of Algal nature, and never presenting determinable characters, very little remains that can be referred to Palaeozoic See also:

• BROWN
• BROWN, CHARLES BROCKDEN (1771-181o)
• BROWN, FORD MADOX (1821-1893)
• BROWN, FRANCIS (1849- )
• BROWN, GEORGE (1818-188o)
• BROWN, HENRY KIRKE (1814-1886)
• BROWN, JACOB (1775–1828)
• BROWN, JOHN (1715–1766)
• BROWN, JOHN (1722-1787)
• BROWN, JOHN (1735–1788)
• BROWN, JOHN (1784–1858)
• BROWN, JOHN (1800-1859)
• BROWN, JOHN (1810—1882)
• BROWN, JOHN GEORGE (1831— )
• BROWN, ROBERT (1773-1858)
• BROWN, SAMUEL MORISON (1817—1856)
• BROWN, SIR GEORGE (1790-1865)
• BROWN, SIR JOHN (1816-1896)
• BROWN, SIR WILLIAM, BART
• BROWN, THOMAS (1663-1704)
• BROWN, THOMAS (1778-1820)
• BROWN, THOMAS EDWARD (1830-1897)
• BROWN, WILLIAM LAURENCE (1755–1830)

Brown Algae . The most striking of all fossil Algae, however, Nematophycus, may possibly be a Phaeophycean . The first species of the genus, Nematophycus- Logani, was discoveredby See also:

• DAWSON, GEORGE (1821-1876)
• DAWSON, SIR JOHN WILLIAM (1820-1899)

Dawson in 1856 in the Lower and See also:

• MIDDLE

Middle Devonian of See also:

• CANADA

Canada, and was described by him as a Conifer under the- name of Prototaxites . Carruthers, however, in 1872 established its Algal nature, and gave it the more appropriate name of Nematophycus . In N . See also:

• LOGAN
• LOGAN, JOHN (1748-1788)
• LOGAN, JOHN (c. 1725-1780)
• LOGAN, JOHN ALEXANDER (1826-1886)
• LOGAN, SIR WILLIAM EDMOND (1798-1875)

Logan the stem, which is found in a silicified state, may be as much as 3 ft. in See also:

• DIAMETER (from the Cr. &a, through, µErpov, measure)

diameter . The tissue is made up of large, unseptate, - occasionally branching tubes, with an undulating See also:

• VERTICAL (from Lat. vertex, highest point)

vertical course, among which, much smaller tubes are irregularly interwoven .

Radially placed gaps in the tissue (at first erroneously interpreted as medullary rays, but subsequently more aptly compared to the See also:

• AIR (from an Indo-European root meaning " breathe," " blow ")
• AIR, or ASBEN

air-spaces of large Algae) contain very sparse hyphae, which here See also:

• BRANCH (from the Fr. branche, late Lat. branca, an animal's paw)

branch more freely than elsewhere . The con-centric rings of growth, which form a characteristic feature, are due to periodic See also:

• VARIATIONS
• VARIATIONS, CALCULUS
• VARIATIONS, CALCULUS OF

variations in the See also:

• SIZE

size of the larger tubes . Transverse septa have occasionally, but rarely, been detected in the smaller' hyphae . See also:

• PENHALLOW, SAMUEL (1665—1726)

Penhallow maintains that these smaller tubes arise as branches from the larger, but other observers have failed to confirm this . In N . Starriei, from the Silurian (See also:

• WENLOCK

Wenlock) of South Wales, described by See also:

• BARBER (from Lat. barba, beard)

Barber, there is no See also:

• SHARP, GRANVILLE (1735-1813)
• SHARP, JAMES (1618-1679)
• SHARP, JOHN (1645-1714)
• SHARP, RICHARD (1759-1835)
• SHARP, WILLIAM (1749-1824)
• SHARP, WILLIAM (1856-1905)

sharp differentiation of the two kinds of tubes; they are rarely observed to branch, except in the gaps, which in this species are not radially directed . In N . See also:

• ORTON, JOB (1717–1783)

Orton (Penhallow), from the Devonian of Canada, the tubes are quite See also:

• UNIFORM

uniform, and there are no spaces or concentric rings . The tubes have their cavity dilated at intervals, and Penhallow has therefore compared them with the See also:

• TRUMPET (Fr. trompette, clairon; Ger. ,Trompete, Klarino, Trummet; Ital. tromba, trombetta, clarino)
• TRUMPET, SPEAKING AND HEARING

trumpet-hyphae of Laminariaceae, but no transverse septa are anywhere visible . Several other species have been described . Carruthers compared the usually non-cellular structure of Nematophycus with that of Siphoneae such as Halimeda, while recognizing the points of resemblance to Laminariaceae (e.g . Lessonia) in the dimensions of the stem and its concentric rings of growth .

- Later writers, influenced by the occasional occurrence of transverse walls in the smaller hyphae, have laid more stress on Laminariaceous affinities . The existence of these gigantic Algae in Palaeozoic times, attested by such well-preserved specimens, is a fact of great interest, though their systematic position is still' an open question: Pachytheca, a spherical organism, usually about the size of a small See also:

• PEA (Pisum)

pea, found in rocks of Silurian and Devonian age, has been much investigated and discussed, without any decisive light having been thrown on its nature . It was once regarded as connected with Nematophycus (with which it sometimes occurs in association), possibly as its fructification . For this view however, there is no evidence, though the tissues of the two fossils are somewhat similar . Pachytheca is formed of cellular filaments resembling those of a Cladophora, irregularly interwoven in the central region, radiating towards the periphery, and often forked . In one case the spherical thallus was found seated in a See also:

• CUP (in O.E. cuppe; generally taken to be from Late Lat. cuppa, a variant of Lat. cupa, a cask, cf. Gr. KuaeXXov)

cup-likereceptacle . There can be little doubt of the Algal nature of the fossil, but beyond this it is impossible at present to carry its determination . On the whole, it cannot besaid that the Palaeozoic remains have as yet thrown much light on the evolution of the Algae, though we may not be prepared to maintain, with Zeiller, that plants of this class appear never to have assumed a form very different from that which they present at the present day . The first evidence for the existence of Palaeozoic Bacteria was obtained in 1879 by See also:

• VAN

Van Tieghem, who found, that in silicified vegetable remains from the Coal Measures of St Etienne Bacterla. the See also:

• CELLULOSE

cellulose membranes showed traces of subjection to butyric See also:

• FERMENTATION

fermentation, such as is produced at the present day by Bacillus Amylobacter; he also claimed to have detected the organism itself . Since that See also:

• TIME (0. Eng. Lima, cf. Icel. timi, Swed. timme, hour, Dan. time; from the root also seen in " tide," properly the time of between the flow and ebb of the sea, cf. O. Eng. getidan, to happen, " even-tide," &c.; it is not directly related to Lat. tempus)
• TIME, MEASUREMENT OF
• TIME, STANDARD

time a number of fossil Bacteria, mainly from Palaeozoic strata, have been described by Renault, occurring in all kinds of fossilized vegetable and See also:

• ANIMAL
• ANIMAL (Lat. animalis, from anima, breath, soul)

animal debris . The supposed Micrococci present little that is characteristic; the more definite, See also:

• ROD (O.E. rodd, probably related to Norw. rudda, stick, rodda, stake)
• ROD, EDOUARD (1857-1910)

rod-like form of the Bacilli offers a better means of recognition, though far from an infallible one; in a few cases dark granules, suggestive of endospores, have been found within the rods . On the whole, the occurrence of Bacteria in Palaeozoic times—so probable a priori—may be taken as established, though the See also:

• ATTEMPT (Lat. adtemptare, attentare, to try)

attempt to discriminate species among them is probably futile; - Fungi were no doubt abundant among Palaeozoic vegetation .

In examining the tissues of fossil plants of that epoch nothing is more common than to meet with mycelial hyphae in Pangl and among the cells; in many cases the hyphae are septate, showing that the higher Fungi (Mycomycetes), as distinguished from the more algoid Phycomycetes, already existed . An endophytic Fungus referred to the latter group (Peronosporites antiquarius, W . See also:

• SMITH
• SMITH, ADAM (1723–1790)
• SMITH, ALEXANDER (183o-1867)
• SMITH, ANDREW JACKSON (1815-1897)
• SMITH, CHARLES EMORY (1842–1908)
• SMITH, CHARLES FERGUSON (1807–1862)
• SMITH, CHARLOTTE (1749-1806)
• SMITH, COLVIN (1795—1875)
• SMITH, EDMUND KIRBY (1824-1893)
• SMITH, G
• SMITH, GEORGE (1789-1846)
• SMITH, GEORGE (184o-1876)
• SMITH, GEORGE ADAM (1856- )
• SMITH, GERRIT (1797–1874)
• SMITH, GOLDWIN (1823-191o)
• SMITH, HENRY BOYNTON (1815-1877)
• SMITH, HENRY JOHN STEPHEN (1826-1883)
• SMITH, HENRY PRESERVED (1847– )
• SMITH, JAMES (1775–1839)
• SMITH, JOHN (1579-1631)
• SMITH, JOHN RAPHAEL (1752–1812)
• SMITH, JOSEPH, JR
• SMITH, MORGAN LEWIS (1822–1874)
• SMITH, RICHARD BAIRD (1818-1861)
• SMITH, ROBERT (1689-1768)
• SMITH, SIR HENRY GEORGE WAKELYN
• SMITH, SIR THOMAS (1513-1577)
• SMITH, SIR WILLIAM (1813-1893)
• SMITH, SIR WILLIAM SIDNEY (1764-1840)
• SMITH, SYDNEY (1771-1845)
• SMITH, THOMAS SOUTHWOOD (1788-1861)
• SMITH, WILLIAM (1769-1839)
• SMITH, WILLIAM (c. 1730-1819)
• SMITH, WILLIAM (fl. 1596)
• SMITH, WILLIAM FARRAR (1824—1903)
• SMITH, WILLIAM HENRY (1808—1872)
• SMITH, WILLIAM HENRY (1825—1891)
• SMITH, WILLIAM ROBERTSON (1846-'894)

Smith) bears very definite terminal, or See also:

• INTERCALARY (from Lat. intercalare, to proclaim, calare, the insertion of a day in the calendar)

intercalary, spherical vesicles, which may probably be regarded as reproductive organs—either oogonia or sporangia . A minute Fungus bearing sporangia, found by Renault in the wood of a Lepidodendron, and named by him 0ochytrium Lepidodendri, is referred with much probability to the Chytridineae . Conceptacles contaning Spores, and strongly suggesting the Chytridineous Fungus Urophlyetis; have recently been found, in petrified material, on the leaves of an Alethopteris, which appears to have undergone decay before fossiliza tion set in . Small spores, almost certainly those of Fungi, are very common in the petrified tissues of Palaeozoic plants . Spherical sacs, bearing forked spines, described by Williamson under the name of Zygosporites, are frequent, usually in an isolated state . See also:

• PROFESSOR (the Latin noun formed from the verb profiteri, to declare publicly, to acknowledge, profess)

Professor Seward, however, has found a Zygosporites in situ, terminating an apparently fungal hypha: he suggests a possible comparison with the mould Mucor . Bodies closely resembling the perithecia of Sphaeriaceous Fungi have often been observed on impressions of Palaeozoic plants, and may probably belong to the group indicated . Professor F . E . See also:

• WEISS, BERNHARD (1827– . )

Weiss has obtained interesting evidence that the symbiotic association between roots and Fungi, known as " Mycorhiza," already occurred among Carboniferous plants .

The few and incomplete data which we at present possess as to Palaeozoic Fungi do not as yet justify any inferences as to the evolution of these plants . The writer is not aware of any evidence for the occurrence of Palaeozoic See also:

• LICHENS

Lichens . The important class of the Bryophyta, which, on theoretical grounds, is commonly regarded as more See also:

• PRIMITIVE

primitive than the ey~ Pteridophyta, is as yet scarcely represented among y~ known fossils of Palaeozoic age . In the Lower Carboniferous of Scotland Mr Kidston has found several specimens of a large dichotomous thallus, with a very distinct midrib; the specimens, referred to the provisional genus Thallites,. much resemble the larger thalloid Liverworts . Similar fossils have been described from still older rocks . In one or two cases Palaeozoic plants, resembling the true Mosses in habit, have been discovered; the best example is the Muscites polytrichaceus of Renault and Zeiller, from the Coal Measures of See also:

• COMMENTRY

Commentry . In the absence, however, both of reproductive organs and of anatomical structure, it cannot be said that there is at present conclusive evidence for the existence of either Hepaticae or Musci in Palaeozoic times . Our knowledge of the Vascular Cryptograms of the Palaeozoic period, though recent discoveries have somewhat reduced their fin, relative importance, is still more extensive than of any dophyta. other class of plants, and in fact it is here that the evidence of Palaeontology first becomes of essential importance to the botanist . They extend back through the Devonian, possibly to the Silurian See also:

• SYSTEM

system, but the systematic See also:

• SUMMARY

summary now to be given is based primarily on the rich materials afforded by the Carboniferous and Permian formations, from which our detailed knowledge of Palaeozoic plants has been chiefly derived . In addition to the three classes, Equisetales, Lycopodiales and Filicales, under which recent Pteridophytes naturally group themselves, a See also:

• FOURTH

fourth class, Sphenophyllales, existed in Palaeozoic times, clearly related to the Horsetails and more remotely to the Ferns and perhaps the See also:

• CLUB (connected with " clump ")

Club-mosses, but with peculiarities of its own demanding an See also:

• INDEPENDENT

independent position . We further find that, whereas the Ferns of the present day form a well-defined and even isolated class, this was not the case at the time when the See also:

• PRIMARY

primary rocks were deposited . A great group of Palaeozoic fossils, showing evident See also:

• AFFINITY (Lat. affinitas, relationship by marriage, from offinis, bordering on, related to; finis, border, boundary)
• AFFINITY, CHEMICAL

affinity to Ferns, has proved to consist of seed-bearing plants allied to Gymnosperms, especially Cycads .

This important class of plants will be described at the beginning of the Spermophyta under the name Pteridospermeae . The arrangement 'which we shall adopt for the Palaeozoic Pteridophyta is therefore as follows: I . Equisetales . II . Sphenophyllales . We must See also:

• BEAR
• BEAR, BLACK
• BEAR, BROWN
• BEAR, GRIZZLY
• BEAR, ISABELLINE
• BEAR, WHITE

bear in mind that throughout the Palaeozoic period, and indeed far beyond it, vascular plants, so far as the existing evidence shows, were represented only by the Pteridophyta, Pteridosperms and Gymnosperms . Although the history of the See also:

• ANGIOSPERMS

Angiosperms may probably go much further back than present records show, there is no See also:

• REASON (Lat. ratio, through French raison)

reason to suppose that they were present, as such, amongst the Palaeozoic vegetation . Consequently, the Pteridophytes, Gymnosperms and their See also:

• ALLIES, THOMAS WILLIAM (1813-1903)

allies had the See also:

• FIELD (a word common to many West German languages, cf. Ger. Feld, Dutch veld, possibly cognate with O.E. f olde, the earth, and ultimately with root of the Gr. irAaror, broad)
• FIELD, CYRUS WEST (1819-1892)
• FIELD, DAVID DUDLEY (18o5-1894)
• FIELD, EUGENE (1850-1895)
• FIELD, FREDERICK (18o1—1885)
• FIELD, HENRY MARTYN (1822-1907)
• FIELD, JOHN (1782—1837)
• FIELD, MARSHALL (183 1906)
• FIELD, NATHAN (1587—1633)
• FIELD, STEPHEN JOHNSON (1816-1899)
• FIELD, WILLIAM VENTRIS FIELD, BARON (1813-1907)

field to themselves, so far as regards the higher plants, and filled places in nature which have now for the most part been seized on by families of more See also:

• MODERN

modern origin . Hence it is not surprising to find that the See also:

• EARLY
• EARLY, JUBAL ANDERSON (1816-1894)

early Vascular Cryptograms were, beyond comparison, more varied and more highly organized than their displaced and often degraded successors . It is among the fossils of the Palaeozoic rocks that we first learn the possibilities of Pteridophytic organization . I . Equisetales.—This class, represented in the recent flora by the single genus Equisetum, with about twenty species, was one of the dominant groups of plants in Carboniferous times .

The Calamarieae, now known to have been the chief Palaeozoic representatives of the See also:

• HORSETAIL (Equisetum)

Horsetail stock, attained the dimensions of trees, reaching, according to See also:

• GRAND

Grand' Eury, a height of from 3o to 6o metres, and showed in all respects a higher and more varied organization than their recent successors . Their remains occur in three See also:

• PRINCIPAL

principal forms of preservation . (I) carbonaceous impressions of the leafy branches, the fructifications and other parts; (2) casts of the stem; these are usually internal, or medullary casts, as described above . Around the cast the organic tissues may be represented by a carbonaceous layer, on the outer surface of which the external features, such as the remains of leaves, can sometimes be traced . More usually, however, the carbonaceous film is thin, and merely shows the impress of the medullary cast within; (3) petrified specimens of all parts—stem, roots, leaves and fructifications—showing the internal structure, more or less perfectly preserved . The correlation of these various remains presents considerable difficulties . Casts surrounded by wood, with its structure preserved, have sometimes been found, and have established their true relations . The position of the branches is shown both on casts and in petrified specimens, and has helped in their See also:

• IDENTIFICATION (Lat. idem, the same)

identification, while the petrified remains some-times show enough of the external characters to allow of their correlation with impressions . Fructifications have often been found in connexion with leafy shoots, and the anatomical structure of the See also:

• AXIS (Lat. for " axle ")

axis in sterile and fertile specimens has proved a valuable means of identification . In habit the Calamarieae appear to have See also:

• BORNE, KARL LUDWIG (1786–1837)

borne, on the whole, a general resemblance to the recent Equisetaceae, in spite of their enormously greater bulk . The leaves were constantly in whorls, and were usually of comparatively small size and of See also:

• SIMPLE

simple form . In the oldest known Calamarian, however, Archaeocalamites (Devonian and Lower Carboniferous), the leaves were repeatedly forked .

There is evidence that in some, at least, of the Calamarieae the leaves of each verticil were united at the See also:

• BASE

base to form a sheath . The See also:

• FREE

free lamina, however, was always considerably more See also:

• DEVELOPED

developed than in the recent family; in form it was usually linear or narrowly lanceolate . Different genera have been founded on leaf-bearing branches of Calamarieae; apart from Archaeocalamites, already mentioned, and Autophyllites (Grand' Eury), in both of which the leaves were dichotomous, we have Annularia, Asterophyllites and Calamocladus (in Grand' Eury's limited sense), with simple leaves . In some species of Annularia the extremely delicate ultimate twigs, bearing whorls of small lanceolate leaves, give a characteristic habit, suggesting that they may have belonged to herbaceous plants; other Annulariae, however, have been traced with certainty Into connexion with the stems of Iarge Calamites . In Asterophyllites, the generic distinction of which from Annularia is not always clear, the narrow linear leaves are in crowded whorls, and the ultimate branches distichously arranged; in the Calamocladus of Grand' Eury—characteristic of the Upper Coal Measures—the whorls are more remote, and the twigs polystichous in arrangement . In all these groups a leaf-sheath has been recognized . The distribution of the branches on the main stem shows considerable variations, on which genera or sub-genera have been founded by C . E . Weiss . In Archaeocalamites, which certainly deserves generic See also:

• RANK (O.Fr. rant or rent, mod. rang, generally connected with the O.E. and O.H.G. bring, a ring)

rank, the branches may occur on every See also:

• NODE (Lat. nodus, a loop)

node, but only In certain parts of the stem; the ribs of successive inter-nodes do not alternate, but are continuous, indicating that the leaves were superposed . Using Calamites as a generic name for all those Calamarian stems in which the ribs alternate at the nodes, we have, on Weiss's system, the following sub-genera: Stylocalamites, branches rare and irregularly arranged; Calamitina, branches in See also:

• REGULAR

regular verticils, limited to certain nodes, which surmount specially See also:

• SHORT, FRANCIS JOB (1857– )

short internodes; Eucalamites, branches present on every node . These distinctions can be recognized on petrified specimens, as well as on the casts, but their taxonomic value is somewhat doubtful .

In many Calamites there is evidence that the aerial stem sprang from a See also:

• HORIZONTAL

horizontal rhizome, as in the common species C . (Stylocalamites) Suckowi; in other specimens the aerial stem has an independent, rooting base . The anatomical structure of all parts of the plant is now known, in various Calamarieae, thanks more especially to the See also:

• WORK

work of Williamson in England and of Renault in France . The stem has a structure which may be briefly characterized as that of an Equisetum with secondary growth in thickness (fig . I, See also:

• PLATE

Plate) . The usually fistulae pith is surrounded by a See also:

• RING (O.E. hring; a word common to Teutonic languages; and probably cognate with the Lat. circus, Gr. KtpKOS or KpLKOS, Skt'. chakra, wheel, circle, cf. also " harangue "); in art, a band of circular shape of varying sizes, made of any material and used f

ring of See also:

• COLLATERAL (from Med. Lat. collateralis,—cum, with, and latus, lateris, side,—side by side, hence parallel or additional)

collateral vascular bundle, (see ANATOMY OF PLANTS, and PTERIDOPHYTA), each of which, with rare exceptions, has an intercellular See also:

• CANAL
• CANAL (from Lat. canalis, " channel " and " kennel " being doublets of the word)

canal at its inner edge, containing the disorganized See also:

• SPIRAL

spiral tracheae, just as in the recent genus . The cortex is often preserved; in certain cases it was strengthened by hypodermal strands of fibres, as in Equisetum . It is only in the rare cases where a very See also:

• YOUNG
• YOUNG, A
• YOUNG, ARTHUR (1741-1820)
• YOUNG, BRIGHAM (1801-1877)
• YOUNG, CHARLES MAYNE (1777–1856)
• YOUNG, EDWARD (1683–1765)
• YOUNG, JAMES (1811-1883)
• YOUNG, THOMAS (1773-1829)

young twig is preserved that the primary structure of the stem Is found unaltered . In all the larger specimens a broad See also:

• ZONE (Gr. 'WV77, a girdle, from 'wvvLvay to gird)

zone of wood, with its elements in radial See also:

• SERIES (a Latin word from serere, to join)

series, had been added . This secondary wood, in the true Calamites (Arthropitys, Goeppert), has a simple structure comparable to that of the simplest Coniferous See also:

• WOODS, LEONARD (1774-1854)
• WOODS, SIR ALBERT (1816-1904)

woods; it is made up entirely of radial bands of tracheides interspersed with medullary rays . The pitting of the tracheides is more or less scalariform in See also:

• CHARACTER (Gr. xapareri7p, from xap&crew, to scratch)

character, and is limited to the radial walls . In favourable cases remains of the cambium are found on the outer border of the wood, and phloem is also present in the normal position, though it does not seem to have attained any considerable thickness .

In the old stems the primary cortex was replaced by periderm, giving rise to a thick See also:

• MASS (O.E. maesse; Fr. messe; Ger. Messe; Ital. messa; from eccl. Lat. missa)
• MASS, IN

mass of bark . The above description applies to the stems of Calamites in the narrower sense (Arthropitys of the French authors), to which the specimens from the British Coal Measures mostly belong . Archaeocalamites appears to have had a similar structure, but in some specimens from the Lower Carboniferous of See also:

• BURNTISLAND

Burntisland, provisionally named Protocalamites pettycurensis, centripetal wood was present in the stem . In Calamodendron (Upper Coal Measures) the wood has a more complex structure than in Calamites, the principal rays including radial tracts of fibrous tissue, in addition to the usual parenchyma . Arthrodendron (Lower Coal Measures) approaches Calamodendron in this respect . The See also:

• LONGITUDINAL

longitudinal course of the vascular bundles and their relation to the leaves in Calamarieae generally followed the Equisetum type, though more variable and sometimes more complex . The See also:

• ATTACHMENT

attachment of the branches was immediately above the node, and usually between two foliar traces, as in the recent genus . Where the structure of the leaves is preserved it proves to be of an extremely simple type; the narrow lamina is traversed by a single vascular bundle, separated by a sheath from the surrounding palisade-parenchyma . Stomata of the same structure as in Equisetum have been detected in the epidermis . The roots (formerly described as a separate genus, Astromyelon) were borne directly on the nodes, not on short lateral branches as in Equisetum . They are of similar structure in all known Calamarieae, the main roots having a large pith, while the rootlets had little or none . The structure is in all respects that typical of roots, as shown by the centripetal primary wood, and the See also:

• ALTERNATION (from Lat. alternare, to do by turns)

alternation of xylem and phloem groups observable in exceptionally favourable young specimens .

A striking feature is the presence of large, radiating intercellular cavities in the cortex, suggesting an aquatic habit . The young roots show a See also:

• DOUBLE
• DOUBLE (from the Mid. Eng. duble, the form which gives the present pronunciation, through the Old Er. duble, from Lat. duplus, twice as much)

double endodermis, just as in the recent Equisetum . A considerable number of Calamarian fructifications are known, preserved, some as carbonaceous impressions, others as petrified specimens, exhibiting the internal structure . In many cases the cones have been found in connexion with branches bearing characteristic Calamarian foliage . Almost all strobili of the Calamarieae are constructed on the same general lines as those of Equisetum, with which some agree exactly; in most, however, the organization was more complex, the complexity consisting in the intercalation of whorls of sterile bracts, between those of the sporangiophores . In several cases heterospory, unknown among recent Equisetaceae, has been demonstrated in their Palaeozoic representatives . Four main types of structure may be distinguished among Calamarian strobili . i . Calamostachys, Schimper . Here the whorls of peltate spor- angiophores alternate regularly with those of sterile bracts, the former being inserted on the axis midway between the latter (fig . 2) . The sporangiophores, which are usually See also:

• HALF

half as numerous in each verticil as the bracts, have the same form as in Equisetum, but each bears four sporangia only .

The spores are frequently found to be still united in tetrads . In some species, e.g. the British C . Binneyana, numerous specimens have been examined and only one kind of spore observed ; here, then, there is a strong pre- sumption that the species was homosporous . In other cases, how- ever, e.g . C . Casheana, Will., two kinds of spore occur, in different sporangia, but on the same strobilus and even on the same sporangiophore . The megaspores, of which there are many in the megasporangium, have a diameter about three times that of the microspores . The See also:

• ABORTION (from Lat. aboriri, to fail to be born, or perish)

abortion of certain spores, which is known to have taken See also:

• PLACE (through Fr. from Lat. platea, street; Gr. IrAar6s, wide)

place both in the homo- sporcus C . Binneyana and in the megasporangia of C . Casheana, may throw some light on the origin of the heterosporous condition . The bracts were sometimes coherent in their lower part (e.g . C .

Binneyana), some- times free (e.g . C . Ludwigi); in all cases their free extremities formed a See also:

• PROTECTION

protection to the fertile whorl above . In some See also:

• CONTINENTAL

continental species (e.g . C . Grand' Euryi, Rea.) radial membranous plates hung down from each verticil of bracts, forming compartments in which the subjacent sporangio- phores were enclosed . The anatomy of the axis is essentially similar to that of a young Calamarian twig, with some variations in detail . Strobili of the Calamostachys type occur in connexion both with Annularia and Asterophyllites foliage . 2 . Palaeostachya, Weiss . Here, as in the previous genus, sterile and fertile verticils are ranged alternately on the axis of the See also:

• CONE (Gr. Kwvos)

cone . The main difference is that in Palaeostachya the sporangiophores, instead of See also:

• STANDING

standing midway between the whorls of bracts, are inserted immediately above them, springing, as it were, from the axil of the sterile verticil (fig .

3, A) . This singular arrangement has suggested doubts as to the correctness of the current See also:

• INTERPRETATION (from Lat. interpretari, to expound, explain, inter pres, an agent, go-between, interpreter; inter, between, and the root pret-, possibly connected with that seen either in Greek 4 p4'ew, to speak, or irpa-rrecv, to do)

interpretation of the Equisetaceous sporangiophore as a modified leaf A Q (After Renault . See also:

• SCOTT, ALEXANDER (fl. 1550)
• SCOTT, DAVID (18o6-1849)
• SCOTT, MICHAEL (1789-1835)
• SCOTT, ROBERT (1811-1887)
• SCOTT, SIR GEORGE GILBERT (1811-1878)
• SCOTT, SIR WALTER, BART
• SCOTT, WILLIAM BELL (1811-1890)
• SCOTT, WINFIELD (1786-1866)

Scott, Studies.) A, Palaeostachya . Diagrammatic longitudinal section of cone, showing the axis (ax) bearing the bracts (br) with peltate sporangiophores (sp) springing from their axils; sm, sporangia . B, Archaeocalamites . Part of cone, showing the axis (ax) bearing peltate sporangiophores (sp) without bracts; sm, sporangia . (cf . Cheirostrobus below) . In most other respects the two genera agree; there is evidence for the occurrence of heterospory in some strobili referred to Palaeostachya . The anatomy of the axis is that of a young branch of a Calamite . According to Grand' Eury, the Palaeostachya fructification was most commonly associated with Asterophyllites foliage . The external aspect of a Palaeostachya is shown in fig .

4 (Plate) . 3 Equisetum type of strobilus . In certain cases the strobili of Palaeozoic Calamarieae appear to have had essentially the sane organization as in the recent genus, the axis bearing sporangiophores only, without intercalated bracts . It is remarkable that fructifications apparently of this kind have been found by Renault in close association with the most ancient of the Calamarieae—Archaeocalamites . In these strobili the peltate scales, like the vegetative leaves of the plant, are in superposed verticils; each appears to have borne four sporangia (fig . 3, B) . Other cones, however, namely, those known as Pothocites, have also been attributed on See also:

• GOOD, JOHN MASON (1764-1827)

good grounds to the genus Archaeocalamites; they are long strobili, constricted at intervals, and it is probable that the succession of fertile sporangiophores was interrupted here and there by the intercalation of sterile bracts, which may also have been present, at long intervals, in Renault's species . Cones from the Middle Coal Measures, described by Kidston under the name of Equisetum Hemingwayi, but probably belonging to one of the Calamarieae, bear a striking external resemblance to those of a recent Equisetum . 4 . Cingularia, Weiss . This form of strobilus, from the Coal Measures of See also:

• GERMANY
• GERMANY (Ger. Deutschland)

Germany,. is imperfectly known, and its relation to Calamarieae not beyond doubt . In the lax strobili the sporangiophores, which are not peltate, but strap-shaped, were borne, as C .

E . Weiss first showed, immediately below the verticils of bracts, the position thus being the See also:

• REVERSE

reverse of that in Palaeostachya . The Palaeozoic Calamarieae, though so far surpassing recent Equisetaceae, both in stature and complexity of organization, clearly belonged to the same class of Vascular Cryptogams . There is no satisfactory evidence for attributing Phanerogamic br affinities to any members of the group, and the view, of which Williamson was the chief See also:

• ADVOCATE (Lat. advocatus, from advocare, to summon, especially in law to call in the aid of a counsel or witness, and so generally to summon to one's assistance)

advocate, that they form a homogeneous Cryptogamic family, is now fully established . II . Sphenophyllales.—The class of Sphenophyllales, as known to us at present, is of limited extent, embracing the two genera Sphenophyllum and Cheirostrobus, which may serve as types of two families within the class . The characters of Sphenophyllum are known with some completeness, while our knowledge of Cheirostrobus is confined to the fructification; the former will therefore be described first . 1 . Sphenophyllum.—The genus Sphenophyllum, of which a number of species have been described, ranging probably from the Middle Devonian, through the Carboniferous, to the Permian or even the Lower Triassic, consisted -of herbaceous plants of moderate dimensions . The long, slender stems, somewhat tumid at the nodes, were ribbed, the ribs See also:

• RUNNING

running continuously through the nodes, a fact correlated with the superposition of the whorled leaves, the number of which in each verticil was some multiple of 3, and usually 6 . In the species on which the genus was founded the leaves, as the generic name implies, are cuneate and entire, or toothed on their anterior margin;, in other cases they are deeply divided by See also:

• DICHOTOMY (Gr. bLya, apart, TEµvew, to cut)

dichotomy into narrow segments, or the whorl consists of a larger number (up to 30) of apparently simple, linear leaves, which may represent the segments of a smaller number . The different forms of leaf may occur on the same plant, the deeply divided foliage often characterizing the main stem, while the cuneate leaves were borne on lateral shoots .

A comparison, formerly suggested, with the two forms of leaf in Batrachian Ranunculi has not proved to hold good; the idea of an aquatic habit is contradicted by the anatomical structure, and the hypo-thesis that the plants were of scandent growth is more probable . The species of Sphenophyllum have a graceful