Page:The Journal of Indian Botany.djvu/249

Rh and in the older mosses no algae are found in contact with rhizoids. But it is at the same time interesting to note that the rhizoidal system is also very much reduced in extent by the death of the finer branches. In these, there is a lot of food material found stored in the bigger rhizoidal branches and most of the finer branches are shrivelled up and non-functional. Here and there, a few algal masses are met with on the plants at the axils of the leaves where some dirt has accumilated and into those also rhizoids from the cortical cells of the stem penetrate. But on the whole, in the older -plants the amount of algae in their vicinity is very little when compared with the younger plants.

The absence of the algae in the later stages of the life of the moss plant may be accounted for by the fact that the conditions near the substratum are no longer favourable to the growth of algae. The moss plants grow very close to each other and to nearly the height of an inch, so that there is very little light available near the substratum. Higher up on the plants themselves the moisture conditions are not favourable except in special situations. But where they occur, rhizoids penetrate them.

The above observations lead the author to believe that the com- mon moss in Madras is parasitic on the blue green algae of the substratum, when the moss plant is young and also in the protonema stage.

Fig. 1. Moss plant with algal masses attached to the rhizoids.

Fig. 2. Mass of protonema filamonts, some with and some without chloroplasts; ends of filaments broken. One germinating gemma also shown.

Fig. 3. Rhizoidal branch encircling an algal colony.

Fig. 4. Rhizoidal branch with short cells encircling algal cells.

Fig. 5. Nostoc colony crushed showing main rhizoidal branches inside.

Fig. 6. Rhizoidal branches entering Nostoc colonies.