In this article we will discuss about the morphology of marsilea with the help of a suitable diagram.
The genus Marsilea with about 60-65 species is distributed in temperate as well as tropical regions. Most of the species occur in Australia and about ten species have been recorded from India.
Marsilea has a slender creeping, dichotomously branched rhizome of indefinite growth, which by forming a mat can extend up to 25 metres in diameter. At each node are borne one or two adventitious roots and an upright leaf (Fig. 10.8A) of flexible petiole and lamina divided into four leaflets.
The leaves give the appearance of four-leaf clover and the plant has been occasionally used as a true substitute for clover. The leaf is circinate when young, and the leaflets are folded together upwards until nearly mature. At night the leaflets are folded upwards assuming a ‘sleeping’ position. Presence of latex in petiole and sleep movement of leaflets are features comparable with angiosperm leaf.
The plants are adapted to grow in shallow water or wet places. A few species also grow on soil. M. hirsuta is an extreme xerophytic form from Australia; capable of surviving long periods of drought and is the only species which forms underground tubers on rhizomes. M. minuta and M. aegyptiaca are also xerophytic forms; the former can grow and form sporocarps in water but the latter grows vegetatively and fails to form sporocarps.
