1907.] 



Fresh-water Algal Flora of Ceylon. 



215 



(ii) The Upland Vegetation. — The following description is based on an 

 examination of the subaerial algal vegetation at Nuwara Eliya and 

 neighbourhood. Although only six days (in the early part of the rainy 

 period) were spent in this region, they were adequate for obtaining a general 

 conception of the character of the subaerial Algae, and I do not consider it 

 likely that other parts of the uplands will differ very materially. Nuwara 

 Eliya lies at a height of 6200 feet above the sea, and close at hand is 

 Pedro tallagalla, the highest point of the island (8296 feet). The rainfall is a 

 fairly high one (91 inches at Hakgalla) and, consequently, the subaerial 

 Algae are well developed, nearly every rock, tree-trunk or embankment being 

 covered with them. This algal growth, however, bears a very different 

 stamp to that of the moist lowlands, whilst Bryophytes and Lichens obtain 

 a foothold, and even attain an abundant development in situations which are 

 dominated by the blue-green Algae in the low country. In all shaded 

 localities, indeed, the greater part of the algal growth becomes completely 

 obscured by Mosses and Lichens ; it is best developed on smooth rock-surfaces 

 or smooth clay-embankments in more or less exposed situations, which are 

 apparently not so favourable for the growth of the other plants mentioned. 

 A point which very soon strikes one with regard to the subaerial Algae of 

 the uplands is the great scarcity of the tufted mode of growth, so 

 characteristic of the wet lower regions. The majority of the Algae altogether 

 exhibit the adhesive type, and by far the most of them are of highly 

 gelatinous consistency. I have put together the following table with the 

 object of showing the relative frequency of the four types of growth in the 

 lowlands, in the country round about Peradeniya and in the uplands ; 

 the percentages are calculated from the actual number of cases examined : — * 



Type of growth. 



Lowlands. 



Peradeniya. 



Uplands. 



1. Adhesive 



Per cent. 

 25 

 34 



56 



Per cent. 

 47'5 

 35-0 

 17-5 



40 



Per cent. 

 66-5 

 26-5 



7-0 



30 



2. Tangled 



3. Tufted 



4. Stratified 



No. of cases examined 



The great prevalence of the adhesive habit is very manifest, and such 

 tufted growth as occurs rarely covers any great extent of surface; tangles 



* The species of Trentepohlia, which always assume a tufted habit, are not taken into 

 account in the calculation of the above table ; their tufts are probably not dependent on 

 exactly the same conditions as the short dense tufts of the Cyanophycese, for they are just 

 as common in the uplands as in the low country. 



