| 释义 |
cotyledon|kɒtɪˈliːdən|
In 6 cotilidon.
[a. L. cotylēdon the plant navelwort or pennywort, a. Gr. κοτυληδών (f. κοτύλη: see prec.) a cup-shaped cavity, the sucker of an octopus, also in senses 1, 2 below. Sense 1 was used in Fr. by Paré (16th c.). The botanical sense 3 was introduced (in mod.L.) by Linnæus.]
1. Phys. One of the separate patches of villi on the fœtal chorion of Ruminants; also applied to the corresponding vascular portions of the uterine mucous membrane.
Formerly applied also to the less separated lobules of the human and other discoid or diffuse placentæ.
1545T. Raynalde Byrth Mankynde ii. vii. (1643) 132 Cotilidons, that is, the veynes by the which the conception and feature is tyed and fastened in the Matrix. 1634T. Johnson tr. Parey's Chirurg. iii. xxiii. (1678) 85 The Cotyledones [of the Uterus]..are nothing else than the orifices and mouths of the Veins ending in that place. 1684tr. Bonet's Merc. Compit. xiv. 513 Cassia..relaxeth the Womb, and weakens the Cotyledons. 1787Hunter in Phil. Trans. LXXVII. 444 Without any small protuberances for the cotyledons to form upon, as in those of ruminating animals. 1869Huxley Introd. Class. Anim. 97 A foetal cotyledon half separated from the maternal cotyledon of a cow.
2. Bot. A genus of plants of the family Crassulaceæ, having thick succulent peltate leaves; the British species is C. Vmbilicus, popularly called Navelwort or Pennywort.
1601Holland Pliny II. 237 Cotyledon, named in Latine Vmbilicus Veneris, is a pretty little herb, hauing..a leafe thick and fatty, growing hollow, like to the concauity wherin the huckle-bone turneth, and therupon it took the foresaid name in Greek. 1741Compl. Fam. Piece ii. iii. 404 We have now..Cotyledons, Chrysanthemums. 1861Miss Pratt Flower. Pl. II. 319 Cotyledon (Penny-wort).
3. Bot. The primary leaf in the embryo of the higher plants (Phanerogams); the seed-leaf.
The number of cotyledons in the seed serves as an important basis of classification of Angiosperms into monocotyledons (= endogens) with one cotyledon, and dicotyledons (= exogens) with two; in Gymnosperms the number varies, being usually more than two.[The term was introduced by Linnæus, and was esp. applied by him to those seed-leaves which are not themselves depositaries of nutriment, but act as organs of absorption, in which he saw an analogy to the function of the cotyledons of the placenta (sense 1). Cf. Gaertner De Fructibus (1788) clxii.] [1751Linnæus Philos. Bot. 54 Cotyledon, corpus laterale seminis, bibulum, caducum. Ibid. 89 Cotyledones animalium proveniunt e Vitello ovi, cui punctum vitæ innascitur; ergo Folia seminalia plantarum, quæ Corculum involverunt, iidem sunt.] 1776J. Lee Introd. Bot. (ed. 3) 410 The Seeds have two Cotyledons. 1845Lindley Sch. Bot. i. (1858) 18 The embryo consists of three parts, the radicle, or young root, the cotyledons, or young leaves, and the plumule, or young stem. 1875Bennett & Dyer Sachs' Bot. ii. v. 443 In some Cupressineæ there are from three to nine, and in some Araucarieæ whorls of four cotyledons; while among the Abietineæ there are..four or even as many as fifteen. |