Page:The Journal of Indian Botany.djvu/244

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The Mosses, though of very common occurrence and of wide distribution, have received little attention from the botanist as regards their physiology of nutrition. In the eighties, there were two opinions about the function of rhizoids in mosses. In 1886, Vaizy showed experimentally that there was no transpiration current in the stem of a moss because no eosin rose into the stem when the cut end was dipped in a solution. Vaizy held that all water absorption wa^ done by the leaves. Later, Haberlandt wrote that, a study of rhizoids in mosses and a consideration of their abundance and extensive branching in the soil, had led him to believe that their function was not merely fixation but was also absorptive, A different aspect of the function of rhizoids is met with in saprophytic mosses, though only very few thorough saprophytes with colourless aerial portions are known. The others have a green aerial portion but their rhizoids penetrate into dead organic substratum. The rhizoids in these are described as being minutely sub-divided and as having the appearance of fungal hyphae with H shaped connections or netted masses.

Observations made by the author on a species cf moss, common in Madras, may be of interest, as they show that the rhizoids are, in the early stages, parasitic on colonies of algae, a habit not hitherto suspected in mosses.

The moss grows on walls coated with lime and exposed to the rains during the monsoon weather. Before the rains, the wall has a debris of old dried up mosses on it. After the rains in two or three days, the dried up stumps put forth a few leaves by the growth of the dormant buds at their tips and small green plants dot the surface of the wall. New rhizoids develop immediately below the cluster of leaves and fresh buds are formed in between the plants from the old rhizoids which contain food material stored in them. At the same time, this portion of the wall and also fresh areas sur. rounding it get coated with a dirty green colour due to the growth