з2 THE FLORA OF SINGAPORE. 
is not rare however to find certain plants of Pigeon orchid which 
do not flower on the regular day, but have a istinc t ay OW which 
they appear to keep to with equal regularity. A curious fact is 
that another species of Dendrobium (D. er отн, үс 
flowers in Singapore on the day preceding that of D. cr poe 
whenever that happens to be. It mi ight be thought that 
weather in the district in which the plant was growing was the 
influencing agent, but this appears to have but little effect on the 
orchids. On one occasion (Dec. 5, 1893) the pigeon orchids 
developed their flowers so far that they were obviously ready to 
open them on that day, but an extraordinarily heavy rain retarded 
them, and the flowers ‘opened the next day, but except in cases like 
this the weather previous to the flowering does not seem to make 
any difference to the date of flowering. “Some few plants have 
a regular annual flowering season ‚ such are Calanthe curculi- 
goides in September, and Gr ammatophyllum, July and August. 
A certain number of trees flower only every fifth е notably 
the Dipterocarper, Every fifth year E appears fo an 
possible to obtain flowers of these trees. Such trees are most of 
the Dipterocarpex, Fo X co Kunstleri, Careya sp. In this 
case also all the plants in a given district flower чононаи 
in Mm Case ^f the Pigeon orchid, beri is difficult to see bow 
this i is brought about. Ag 1 шапу Mas seem to flower even 
t 
apparently full grown healthy trees have not given flowers once 
їп ten years 
Colors of flowers. 
As is well known the colors of thowers depend to a large 
extent on the kind of iusect fertilizer for which they are destined 
to prove attractive. The most abundant insects in the thick 
jungle are the flies ( Diptera) and these appear often in enormous 
abundance when certain trees are in bloom. The Oaks aad 
