| 释义 |
‖ rostellum|rɒˈstɛləm|
[a. L. rostellum a small beak or snout (Pliny), dim. of rostrum.]
1. Bot.
a. A radicle: cf. rostel. ? Obs.
1760J. Lee Introd. Bot. i. vii. (1765) 15 Rostellum, a plain Part of the Corculum; which descends. 1797Encycl. Brit. (ed. 3) III. 435/2 The Corculum..consists of two parts, viz. plumula and rostellum. 1832Lindley Introd. Bot. (1839) 250 The radicle..(rhizoma or rostellum); cotyledons..; and plumule.
b. (See quots.)
1841Penny Cycl. XX. 175/2 Rostellum..is applied to the short beak-shaped process found on the stigma of many violets, as Viola hirta, V. odorata, and V. canina, &c.; and Orchidaceæ, as Orchis, Spiranthes, Listera, &c. 1849Balfour Man. Bot. §421 In Orchids, each of the pollen masses has a prolongation or stalk,..which often adheres to a prolongation at the base of the anther, called rostellum. 1862Darwin Orchids Introd. 6 The rostellum either includes or is formed of viscid matter.
2. Zool.
a. The tubule and enclosed siphuncle of the various species of louse, replacing the usual mouth apparatus of insects.
1826Kirby & Sp. Entomol. III. 363.
b. The protruding fore-part of the head of tapeworms, armed with hooklets or spines.
1849in Craig. 1856–8W. Clark Van der Hoeven's Zool. I. 180 Tænia... Head with four suctorial oscules, and mostly with a rostellum median, imperforate, retractile. 1888Rolleston & Jackson Anim. Life 225 Taenia elliptica..also possesses a peculiar round rostellum beset with four irregular rows of sixty small hooks. |