Psilophyta


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The following article is from The Great Soviet Encyclopedia (1979). It might be outdated or ideologically biased.

Psilophyta

 

a division of extinct higher plants the remains of which have been traced to the Silurian and Lower and Middle Devonian periods. The Psilophyta had dichotomously branching stems. Leaves and roots were absent, and sporangia were borne on the ends of the shoots. The stem had a thin central cylinder (stele) with protoxylem in the center, and it was covered with a stomatous epidermis. The plants were marked by homospory. The Psilophyta are regarded as the primitive group that gave rise to higher cormophytic plants.

The Great Soviet Encyclopedia, 3rd Edition (1970-1979). © 2010 The Gale Group, Inc. All rights reserved.
References in periodicals archive ?
There are three extinct (Rhyniophyta, the oldest; Timerophyta, fossil found 350 million years ago, and Zosterophyllophyta, early Devonian 375 millions years ago) and four living divisions (Lycophyta, a group of herbaceous line; Sphenophyta, horsetail's jointed stems; Psilophyta, epiphytes; and Pterophyta, the ferns).
In contrast to seed plants, ferns and fern allies (i.e., Pterophyta, Lycophyta, Sphenophyta, Psilophyta) have a free-living haploid gametophyte stage whose population dynamics affect the reproductive capacity and fitness of both gametophyte and sporopbyte generations.