whisk ferns; comprising the family Psilotaceae or Psilotatae: vascular plants with no roots, partial if any leaf differentiation, and rudimentary spore sacs.
蕨类植物；由松叶蕨科或裸蕨纲组成；无根脉管植物，叶仅部分分化或缺乏，孢子囊发育较差。
from 345 million to 405 million years ago; dominance of fishes and appearance of amphibians and ammonites.
保存着大量的蕨类植物,石松纲植物,木贼属和裸子植物以及大量的低级鱼类。
any plant or fossil of the genus Psilophyton.
裸蕨属的一种植物或化石。
Psilophyta (whisk ferns) In the Five Kingdoms classification scheme, a phylum of vascular seedless plants, the whisk ferns.
裸蕨植物门(松叶蕨)：在五界分类系统中，一门不产生种子的维管植物，松叶蕨。
terrestrial tropical ferns having fronds with powdery yellowish or white undersides; sometimes placed in family Polypodiaceae or Adiantaceae.
陆生的热带蕨属，叶下面呈淡黄色或白色，粉状；有时归入水龙骨科或裸子蕨科。
small family of lower ferns having nearly naked stems and minute scalelike leaves.
低等蕨类植物小科具有接近赤裸的茎和微小的鳞状的叶。
green plant having a vascular system: ferns, gymnosperms, angiosperms.
有脉管系统的绿色植物：蕨类植物，裸子植物，被子植物。
fossil gymnospermous trees or climbing plants from the Devonian: seed ferns.
裸子植物化石树或攀缘植物，起源于泥盆纪；种子蕨。
used in some classification systems: a group of extinct fossil gymnosperms coextensive with the order Cycadofilicales.
用于某些分类系统中；一个灭绝的裸子植物化石群，与苏铁蕨目同域。
used in former classifications to include all ferns and flowering plants and divided into the three classes Filicinae and Gymnospermae and Angiospermae.
用于旧的分类中，包含所有蕨类植物和开花植物并分为三个纲。
These plants belong to 28 families and 42 genera and include 5 species of pteridophyte,10 species of gymnospermae and 35 species of angiospetmae.
这50种植物分属28科42属,其中蕨类植物5种,裸子植物10种,被子植物35种。
These plants belong respectively to 12 families and 13 genera,including 2 species of pteridophytes,1 species of gymnospermae and 10 species of angiospetmae.
这13种植物分属12科,13属,其中蕨类植物2种,裸子植物1种,被子植物10种;
A multicellular, often flask - shaped, egg - producing organ occurring in mosses, ferns, and most gymnosperms.
藏卵器在苔藓、蕨类及大多数裸子植物中的多细胞的，常为烧瓶状的产生卵子的器官
type genus of the Psilophytaceae: genus of small wiry herbaceous Paleozoic plants with underground rhizomes and apical sporangia.
裸蕨科的模式属；古生代植物，为小而坚韧的草木，具地下根状茎和顶生的孢子囊群。
extinct gymnosperms most of Carboniferous to Jurassic: seed ferns and allies.
生活于石炭纪至侏罗纪的大部分时间的现已灭绝的裸子植物；种子蕨及同源植物。
any of various marine gastropods of the suborder Nudibranchia having a shell-less and often beautifully colored body.
裸鳃亚目的多种海栖腹足纲软体动物，无壳，通常体色美丽。
cone-bearing gymnosperms dating from the Carboniferous period; most are substantial trees; includes the classes Pinopsida (subdivision Pinophytina) and Ginkgopsida (subdivision Ginkgophytina) and Taxopsida (subdivision Taxophytina) which in turn include the surviving orders Coniferales and Taxales (yews) and sometimes Ginkgoales as well as extinct orders such as Cordaitales (of the Carboniferous and Permian) and Volztiales (of the Permian-Jurassic).
产生于石炭纪的有球果的裸子植物；大部分为坚硬乔木；包含松柏纲（松柏亚部）。
any of several ferns of the genus Blechnum.
乌毛蕨属的蕨类植物。