332 MR. H. H. W. PEARSON ON THE 
cn the east than on the west side of tall plants. This is very 
marked in the Rhododendron, the shrubs Hypericum mysorense, 
Atylosia Candollei, ete., and the Jungle-trees. It is probably 
due largely to the mechanical injuries inflicted by the wind on 
the buds on the west side of the tree; the chilling effect of 
the moisture-laden air also has a greater effect on the west than 
on the east side. The dwarfing effect of the wind is seen ina 
remarkable manner in ascending from the Hakgala Botanic 
Gardens (5600 ft.) to the top of the steep Hakgala rock 
(7000 ft.) behind them. At 5600 feet the trees are 30 feet or 
more in height, but gradually diminish in size as the higher and 
more exposed parts of the hill are reached; at the summit, the 
arborescent vegetation is composed of knee-high, crooked and 
gnarled specimens of species which attain the normal height a 
thousand feet lower down; and in these the majority of the 
buds develop on the east side. The prevailing direction of the 
illumination is probably another factor in produeing this eastward 
development of shrubs and trees in the Hakgala valley. During 
both monsoons it is a common experience, on the eastern slopes 
of the main ridge, that the mornings are fine while the afternoons 
are cloudy or wet. This generalization is borne out by the 
following figures, which give the mean proportion of clouded 
sky * at 9.30 a.m. and 3.30 P.M. respectively for each month 
during 1897 at Hakgala (55). 
| = | | FEN 
. . H = o . = 
ag | 2 S | |e) 6/4 wl A D | D 3 [9| 
| E | a |e AA | 5 lall OTA TA I 
nn — |— eg | Bn 
19.30 am] 52 38 36 44 146 72,60|72| 66 48 62 15,59 
13.30 P.M. | D'Y DS 73 | 81 | 77 | TRIT2| 916 T3 | 88 | 8:8 d TI 
| 
It follows from these figures that a markedly larger propor- 
tion of direct sunlight falls on the Hakgala and Sita Eliya patanas 
during the morning than in the afternoon, and therefore the 
eastern side of a tall plant receives more direct illumination than 
the western. 
List of Plants. 
On pp. 334-362 is given a complete list of the plants collected 
on the patanas during the period indicated above. In a few cases 
a plant which was not eollected is given as a patana- plant” 
on the authority of Trimen. 
ke 10 denoting a sky entirely and continuously overcast, and zero a cloudless 
sky. 
