In this article we will discuss about the external features of marsilea. 1. Plant body (Fig. 258) is sporophytic and the sporophyte possesses a rhizome; having man) roots arising towards lower side and leaves towards the upper side. 2. Rhizome is long, slender, well-branched and grows on or below the soil surface and may attain a length of several metres [...]
Observe the external features of the plant, and arrangement, types and shape of leaf, ligule, rhizophore and roots. 1. Plant body is sporophytic and the sporophyte is evergreen and perennial. 2. Most of the species are prostrate but Selaginella trachyphylla is sub-erect and S.erythropus is erect (Fig. 208). 3. Size of the sporophyte ranges from few centimetres to several feet [...]
In this article we will discuss about:- 1. History of Heterospory 2. Incipience of Heterospory 3. Origin 4. Evidences 5. Advantages. History of Heterospory: Pteridophytes are the first true land plants. Being the first successful colonisers in land habit pteridophytes show both the homospory and heterospory. Most of the pteridophytes are homosporous, produce isospores which are morphologically and physiologically identical. [...]