In this article we will discuss about the process of reproduction in selaginella with the help of diagram. Selaginella is heterosporous. Two types of sporangia (larger ones megasporangia and smaller ones microsporangia) containing larger and smaller spores are borne on sporophylls which form cones terminally either on the stem or branches. The cones are inconspicuous due to small size and [...]
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 [...]