In this article we will discuss about the asexual and sexual modes of reproduction in marchantia with the help of diagrams. Asexual Reproduction in Marchantia: Asexual propagules - gemmae - occur in a gemma-cup (Fig. 2.6A). On the floor of the cup are seen numerous mucilage papillae and many biconvex discoid gemmae (Fig. 2.7E). A gemma (Fig. 2.7F) is borne [...]
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 [...]