WHEAT (Triticum) , the most important and the most generally diffused of cereal
See also:grasses . It is an
See also:annual plant, with hollow, erect, knotted stems, and
See also:pro- duces, in addition to the
See also:direct developments from the seed-
See also:ling plant, secondary roots and secondary shoots . (tillers) from the
See also:base . Its leaves have each a long sheath encircling the
See also:stem, and at the junction of the blade or "
See also:flag " with the sheath a small whitish out-growth or " ligula." The in-florescence or ear consists of a central stalk bent zigzag, forming a series of notches (see fig . 1), and bearing a number of flattened spikelets, one of which grows cut of each notch and has its inner or upper
See also:face pressed up against it . At the base of each spikelet are two empty
See also:boat-shaped glumes or "chaff-scales," one to the right, the other to the
See also:left, and then a series of
See also:flowers, 2 to 8 in number, closely crowded to- E. gether; the uppermost are abortive or sterile, indeed, in some varieties only one or two of the flowers are fertile . Each flower consists of an
See also:outer or
See also:lower glume, called the flowering glume, of the same shape as the empty glume and terminating in a long, or it may be in a
See also:short, awn or "
See also:beard." On the other side of the flower and at a slightly higher level is the " palea," of thinner texture than the other glumes, with infolded margins and with two ribs or
See also:veins . These several glumes are closely applied one to the other so as to conceal and protect the ovary, n ~ r A, Spikelet magnified . B, Glumes, from side . C, Glumes, from back . D, Flowering glume or lower palea . E, Palea .
F, Lodicuies at base of j, the ovary, surmounted by styles . G and H, Seed from front and back respectively . I, Rachis, or central stalk of ear, spikelets removed . and they only
See also:separate for a short
See also:time when flowering takes place; after fertilization they close again . Within the
See also:pale are two minute, ovate, pointed,
See also:white membranous scales called " lodicules." These contain three stamens with
See also:thread-like filaments and oblong, two-lobed anthers . The stamens are placed
See also:round the base of the ovary, which is rounded or oblong, much smaller than the glumes, covered with down, and sur- mounted by two short styles, extending into feathery
See also:brush-like stigmas . The ripe fruit or
See also:grain, sometimes called the "
See also:berry," the matured state of the ovary and its contents, is oblong or ovoid, with a
See also:longitudinal furrow on one side . The ovary adheres firmly to the seed in the interior, so that on examining a longi- tudinal section of the grain by the microscope the outer layer is seen to consist of epidermal cells, of which the uppermost are prolonged into short hairs to cover the
See also:apex of the grain . Two or three layers of cells inside the epidermis constitute the tissue of the ovary, and overlie somewhat similar layers which
See also:form the coats of the seed . Within these is the albumen or endo- sperm, constituting the flowery
See also:part of the seed . The outermost layer of the endosperm consists of square cells larger and more
See also:regular in form than those on each side; these contain aleuron grains— small particles of
See also:gluten or nitrogenous
See also:matter . The remaining central mass of the seed is com- posed of numerous cells of irregular form and
See also:size containing many
See also:starch grains as well as gluten granules .
The several layers of cells above re- ferred to become more
See also:Polish wheat, with seed . III . Spelt able one from another, -vheat . All much reduced . forming the substance known as "
See also:bran." At the lower end of the albumen, and placed obliquely, is the minute embryo-plant, which derives its nourishment in the first instance from the albumen; this is destined to form the future plant . The wheat plant is nowhere found in a
See also:condition . Some of the
See also:species of the genus Aegilops (now generally referred to Origin and Trilicum by Bentham and
See also:Hooker and by
See also:Haeckel) species. may possibly have been the
See also:sources of our cultivated forms, as they
See also:cross freely with wheats . Haeckel considers that there are three species . (1) Triticum monococcum, which undoubtedly grows wild in
See also:Greece and
See also:Mesopotamia, is cultivated in Spain and elsewhere, and was also cultivated by the aboriginal Swiss lake-dwellers, as well as at Hissarlik, as is shown by the grain' found in those localities . (2) T. salivum is the ordinary cultivated wheat, of which Haeckel recognizes three
See also:principal races, spelta, dicoccum and tenax . Spelt wheats (see fig . 2) were cultivated by the aboriginal Swiss, by the
See also:ancient Egyptians, and throughout the
See also:empire .
The variety dicoccum was also cultivated in prehistoric times, and is still grown in
See also:Europe as a summer wheat and one suitable for starch-making . The variety tenax includes four sub-races, vulgare (
See also:common wheat), compactum, turgidum and durum (see below) . (3) The third species, T. polonicum, or Polish wheat, is a very distinct-looking form, with long leafy glumes; its origin is not known . As these varieties intercross with each ' See drawings made to scale by Mr Worthington
See also:Smith in the Gardener's
See also:Chronicle (25th
See also:December 1886) .
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