File:Lectures on the physiology of plants (1887) (14778931144).jpg

Identifier: lecturesonphysio00sach (find matches)
Title: Lectures on the physiology of plants
Year: 1887 (1880s)
Authors: Sachs, Julius, 1832-1897
Subjects: Plant physiology
Publisher: Oxford : The Clarendon Press
Contributing Library: NCSU Libraries
Digitizing Sponsor: NCSU Libraries

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e into theseed, capable of germinating, the partsof which must be understood beforea proper insight can be obtained into its origin and significance. This can beaccomplished with the aid of Fig. 437, which represents the germination of the seedof the Stone Pine, with which the other Coniferae essentially agree. / is the seedin longitudinal section, consisting of three parts; i- the hard thick testa developedfrom the integument of the ovule after fertilisation ; c is the so-called endosperm, orfurther developed prothallium—the black line separating the testa and endosperm isto be supposed to represent the membrane of the macrospore, or, what is the sameÜiing, the embryo-sac. Finally, we have lying in the middle of the endosperm theyoung embryo : zv is its incipient root, c a whorl of leaves which, owing to an extremelyunhappy idea of the older botanists, it is still the custom to term cotyledons. Thisagain is an entirely meaningless word, which however unfortunately can now scarcely
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Fig. 436 — Tnxits bacrata. A male flower(enlarged): a the pol.en-sacs. B an antherwith the pollen-sacs opened, seen from below.C portion of a leaf-.shoot, with a foliage-leaf1^, from the axil of which springs the fen-.aleflower ; j its scales ; sk its terminal ovule. Dlongitudinal section of the ame (magnified):/integument; kk nucelius of the ovule; a-arudimentary axillary ovule. D longitudinalsection through an older ovule, before fertili-sation : i integument; kk nucellus ; e endo-sperm; m arillus ; s enveloping leaves. DIFFERENCES BETWEEN SPORES AND SEEDS, 753 be expunged from scientific language ; it may be translated seed-leaves. It issimply bad taste however to speak of them as seed-lobes. The rest of the drawings in Fig. 437, concerning which the explanation of thefigure gives further information, show how the germ-plant (the embryo) containedin the seed, then developes further ;how first the root cv and then theprimary shoot-axis x elongates andemerges from the seed: the rad

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