Page:The Journal of Indian Botany.djvu/248

210 way the algal cells were attacked by the rhizoidal branches. But usually, either mixed up with the small cells of the colonies or independently, bigger cells of a different species of alga are met with. A few such are shown in Figs. 3 and 4 with the rhizoidal branches, which here consist of short cells, surrounding the algal cells and closely adpressed to them.

But even in these cases no special structures of absorption such as haustoria have been noticed. That haustoria are not a necessary condition for parasitic or symbiotic relationship is shown in the cases of many fungi and also lichens.

The effect of the intimate contact with the algal colonies is seen very clearly. At the beginning, the algal cells are full of protoplasm with bright blue-green colour and have a healthy vigorous appearance. But gradually the colour fades and the contents disappear. Some of the cells of a colony remain vigorous and healthy whereas others are completely or partly decayed. Scytonema filaments, with the portions in contact with the rhizoidal branches in a decaying condition, are quite common. At still later stages, the individual cells of the colonies are not recognisable and only a debris of cell-walls is left. In the case of Scytonema, the thick sheaths devoid of their contents are often met with surrounding the rhizoidal branches.

In plants, which had not been growing for more than a fortnight, large quantities of food material are often found stored up in the rhizoids whose minor branches penetrate into the algal masses. And it is not uncommon to find some of the branches inside the algal masses swollen and full of food material. It is evident that the plants themselves could not have manufactured all this food material by the activity of its green parts, within such a short time and it gives room to a very strong presumption for an external source of the food material. The extraordinary minute branching of the rhizoids, and the intimate contact of the branches with the algal colonies which resembles the behaviour of the fungal hyphae occurring between the algal cells in the Lichens, further strengthens the presumption, that the relation between the moss rhizoids and the algie, is very likely to be one of parasitism of the rhizoids on the algal colonies. My friend Mr. M. O. Parthasarathy Iyengar collaborates my observation and says that in his wanderings in search of algae he had repeatedly noticed that the young moss plants invariably appear only on substrata which are first covered over with blue green algae. He is inclined to believe that the same thing holds good for the common Liverworts which appear immediately after the monsoon in Madras.

As the mosses grow taller, the algae on the substratum disappear