rostellum

n. 顶突, 小喙 [医] 顶突

词形变化

rostella 复数 rostella rostellums rostellums 复数

释义与例句

n.
  1. 1.

    A small beak-like process or extension; a small rostrum.

    the rostellum of the stigma of violets, or of the operculum of many mosses

  2. 2.

    A projecting part of the column in the flower of an orchid that separates the male stamen from the female gynoecium.

    生物 植物学

    1922, John Christopher Willis, "Orchidacea", entry in A Manual and Dictionary of the Flowering Plants and Ferns, page 471, The rostellum has an outer firm pouch, inside which is the viscid substance to which are firmly attached the caudicles of the pollinia. An insect entering the fl. probes the spur of the labellum and its back comes into contact with the rostellum and depresses the pouch, causing the viscid substance to adhere to the insect.

    2005, Orchids of Manitoba: A Field Guide, Native Orchid Conservation Inc., page 20, The third stigma is sterile and has developed into the rostellum, a sticky structure that aids in pollination by attaching the pollen to insects.

  3. 3.

    A retractable protruding part at the anterior end of a soft-bodied tapeworm; the scolex from which it protrudes is often armed with hooks which serve to keep it in place attached to the host.

    生物

词源

From Latin, diminutive of rostrum (“beak”).

来源：wiktionary