Volume 4, Issue 1
July 1936, pages 1-65
pp 1-26 July 1936
pp 27-35 July 1936
pp 36-44 July 1936
Very little work has been done on the ecology of the freshwater algæ of North India, and this is, as far as I know, the first attempt in this field. Under such circumstances, it may be expected that considerable variety of opinion be entertained by various algologists as to the best method of arranging the various forms in Groups, Subgroups, Sections and Sub-Sections. The author realises that more intensive work is required in this field, and his conclusions in some cases may not be all what is desired. However, he hopes that his efforts will stimulate the workers, who have better facilities than he has for this sort of work.
pp 45-51 July 1936
pp 52-65 July 1936
The leaves ofArenaria musciformis andThylacospermum rupifragum show superficial stomata, abundance of intercellular spaces in the mesophyll which consists of entirely spongy tissue.
The primary structure and early secondary growth in the stem and root ofArenaria are more or less normal, but it is found that during later stages of development the activity of the cambium suffers at some points of its extension and this gives rise to furrowing in the wood especially in the root.
The young stems and roots ofThylacospermum possess the normal dicotyledonous structure, but later the cells of wood parenchyma become highly meristematic and ultimately split the stele into numerous irregular vascular strands in a manner similar to that found in some tropical lianes. This type of anomalous secondary thickening is new for the familyCaryophyllaceœ and also for the order Centrospermales itself. It is suggested that inThylacospermum it originated independently of any ancestral climbing habit. The cause of its origin is most probably of a mechanical nature.