In this article we will discuss about the morphology of psilotum with the help of a suitable diagram. Also learn about its phylogenetic position. Two species of Psilotum recognized are P. nudum and P. flaccidum (P. complanatum). Of these P. flaccidum is a pendulous epiphyte, rare in distribution; restricted to Jamaica, Mexico, Hawaii and a few Pacific islands. On the [...]
in this article we will discuss about the modes of reproduction in psilotum with the help of diagrams. Stout aerial branches bear large conspicuous sporangia (Fig. 7.1 A). Each sporangium is a 3-lobed structure (Fig. 7. 1B, C). It is borne on a forked appendage. It has been described as: (a) Trilocular sporangium (b) Trisporangiate structure, and (c) A synangium; [...]
An earliest record of vascular plants is from Devonian of Canada (Gaspe Peninsula, Quebec). Although the compressions were fragmentary, a reconstruction revealed slender axes arising from a subterranean rhizome system (Fig. 7.3A). The rhizome lacked roots but had rhizoids. The aerial axes were dichotomously branched with scale-like appendages and terminated into sporangia. Because of its similarity with Psilotum. the plant [...]