[医] 蕨类植物

[ noun ]
containing all the vascular plants that do not bear seeds: ferns, horsetails, club mosses, and whisk ferns; in some classifications considered a subdivision of Tracheophyta
<noun.plant>

Pteridophyta \Pter`i*doph"y*ta\, n. pl. [NL., from Gr. ?, ?, a
fern + ? a plant.] (Bot.)
A class of flowerless plants, embracing ferns, horsetails,
club mosses, quillworts, and other like plants. See the Note
under {Cryptogamia}. -- {Pter"i*do*phyte`}, n.

Note: This is a modern term, devised to replace the older
ones acrogens and vascular Cryptogamia.


Vascular \Vas"cu*lar\, a. [L. vasculum a small vessel, dim. of
vas vessel: cf. F. vasculaire. See {Vase}, and cf. Vessel.]
1. (Biol.)
(a) Consisting of, or containing, vessels as an essential
part of a structure; full of vessels; specifically
(Bot.), pertaining to, or containing, special ducts,
or tubes, for the circulation of sap.
(b) Operating by means of, or made up of an arrangement
of, vessels; as, the vascular system in animals,
including the arteries, veins, capillaries, lacteals,
etc.
(c) Of or pertaining to the vessels of animal and
vegetable bodies; as, the vascular functions.

2. (Bot.) Of or pertaining to the higher division of plants,
that is, the ph[ae]nogamous plants, all of which are
vascular, in distinction from the cryptogams, which to a
large extent are cellular only.

{Vascular plants} (Bot.), plants composed in part of vascular
tissue, as all flowering plants and the higher
cryptogamous plants, or those of the class {Pteridophyta}.
Cf. {Cellular plants}, {Cellular}.

{Vascular system} (Bot.), the body of associated ducts and
woody fiber; the fibrovascular part of plants.

{Vascular tissue} (Bot.), vegetable tissue composed partly of
ducts, or sap tubes.

{Water vascular system} (Zo["o]l.), a system of vessels in
annelids, nemerteans, and many other invertebrates,
containing a circulating fluid analogous to blood, but not
of the same composition. In annelids the fluid which they
contain is usually red, but in some it is green, in others
yellow, or whitish.