The production of two kinds of spores differing in structure and function, the smaller one producing the male gametophyte and larger one producing the female gametophyte, is termed heterospory. For the first time distinct heterospory (structural as well as functional) is evident in pteridophytes; but out of several hundred forms in the group, only 9 genera (Selaginella, Isoetes, Stylites, Marsilea, [...]
The shoots in Selaginella are characterized by the possession of meristems (dorsal and ventral) at each branching. These angle-meristems produce roots. In contemporary literature these outgrowths are designated as 'rhizophore'. However, studies of auxin transport in these structures have conclusively proved their nature as root. Employing labelled auxin (C IAA), it is shown that auxin transport in rhizophores of S. [...]
In this article we will discuss about the origin of seed in selaginella. An evolutionary sequence of origin of seed from homosporous form should involve: (a) Production of two kinds of spores, (b) Reduction in the number of functional megaspores, (c) Final reduction to a single megaspore in the sporangium, (d) Retention of megaspore within the megasporangium, (e) Elaboration of [...]