7 
Flora of the Ceylon Littoral. 
the seedling in such a position is very slow, the internodes are very 
short and the leaves very small (not more than a third of an inch 
long), deeply cleft and very succulent (Fig. 3d). On the other hand 
the plant is sometimes to be met with ( e.g . at Malacca) growing most 
luxuriantly on mud, with enormous leaves six inches across, thin 
and practically entire, i.e. orbicular-cordate with the apices only 
slightly retuse (Fig. 3a and b ). 1 
Spinifex squarrosus is another pioneer plant, but stands rather 
apart from the rest in some respects, although it possesses the same 
general habit. It is a bulky, very rigid, tough glaucous grass, which 
tends to form “ pure ” formations excluding other species. It is well 
described by Schimper (Indo-.Malayische Strandflora, p. 80), and its 
method of seed-distribution by the detachment of the ripe heads, 
which are driven by the wind for long distances over the sand, is 
well known. When in flower the enormous spherical heads of 
spikelets with stiff pointed radiating “ spindles ” are very conspicuous. 
We found this plant particularly common in the drier regions 
to the north and to the east of the wet zone which forms the centre 
of the stretch of coast under consideration, e.g. especially abundant 
at Negombo (61 inches of rain), Hambantota (36 inches) and 
Trincomalie (63 inches), though it undoubtedly also occurs at various 
spots in the wetter region (e.g. to the south of Bentotta—over 100 
inches). Ipomcea biloba seems to diminish as Spinifex increases, in 
passing from the wetter to the drier region ; thus at Tangalla (40 
inches), about midway between Matara (69 inches) and Hambantota 
(36 inches) Ipomcea was developed in far less abundance than 
at Matara, although no Spinifex was found here ; at Hambantota 
Spinifex is present alone and no Ipomcea was seen. On the other 
hand in some of the drier localities, e.g. Negombo and Trincomalie, 
both Ipomcea and Spinifex occur side by side; at the latter locality 
Ipomcea forms a fringe just above high tide-mark, holding the ground 
almost alone, whilst the Spinifex occupies the inner zone. It is 
possible that the growth of Spinifex is favoured by a dry locality, 
and the abundant development of this hardy plant might readily 
exclude a growth of the Ipomcea. Whether this relation really holds 
good can only be determined by more thorough observation. 
A number of plants of similar habit accompany Ipomcea on the 
Ceylon coast, and sometimes replace it to a certain extent. Of 
these one of the commonest and most successful, growing along 
1 We are indebted to Dr. Stapf, of Kew, for confirming our deter¬ 
mination of these extraordinarily diverse forms as all 
belonging to I. biloba. 
