Calcicolous associations of the Bombay state

Abstract

In the present investigation, we have surveyed the calcicolous associations of Neral which is 56 miles south of Bombay; Khandala and Lonavala which are only 6 miles apart from each other and 76 and 82 miles south of Bombay respectively; the other two are hills, Matheran and Purandhar. Matheran is approachable from Neral by rail and road and is 56 miles from Bombay and Purandhar is 152 miles S.E. of Bombay and is approachable via Poona. At the outset it may be mentioned that all these associations are purely seasonal and occur only during the monsoon. After October all the plants constituting them dry up except a few perennials like Blumea membranacea DC., Lindenbergia urticaefolia LINK & OTTO., Tridax procumbens LINN. and Kickxia ramosissimna Boiss. The associations are found generally on the walls which are built either of stone or rocks cemented together with lime-mortar or mud. Some of the walls are fairly new and are built with cement-mortar which contains a high percentage of calcium car bonate. We have also come across a few brick walls held together either by lime-mortar or more crudely with mud and cow dung. This aspect of the old and new walls is important since the former are more thickly covered with vegetation and are generally dominated by Adiantum lunulatum BURM. and give a better idea of plant succession. Whatever the type of wall, its composition, in so far as the binding material is concerned, bears an amount of calcium either in the form of calcium carbonate or as exchangeable calcium, which is not usually found in the ordinary plant substratum. The calcium carbonate content varies on an average from 4.90 to 59.19% and its ex changeable calcium content varies from 22.89 to 73.92 m.e. per 100 gms. of the soil. The total replaceable bases range from 34.5 to 89.2 m.e. per 100 gms. of the soil. There fore, these soils are more than 100 percent saturated with calcium and hence, both from the calcium carbonate and the available calcium point of view, the associations found on them can be designated as calcicolous. Since the above four associations are all dominated by four different species of the same genus, Arthraxon, we have named them after their dominant and their most characteristic species. Thus we distinguish four associations of Arthraxon lancifolius HOCHST., Arthraxon quartinianus NASH., Arthraxon inermis HOOK., and Arthraxon