eee at 
APOSTASIACEZ OF THE MALAY PENINSULA. 337 
I believe that there is actual growth of the column apex, 
and this is borne out by the alteration in form of the spots on 
the upper part of the column, which appear to lengthen as the 
column curves over. 
Removal of the pollinia does not arrest this growth. 
The same growth takes place after fertilization, but much 
more rapidly. On November 27th, at 11 a.m., I fertilized two 
flowers with the pollen of each other. Next day, at 8.30 a.m., 
the column was distinctly curved over and nearly concealed 
the stigma, and by noon the curving into the stigma was 
complete. Meanwhile the lower flowers on the raceme, which 
had been open for some days, had not commenced to alter 
at all. 
All the flowers I fertilized set fruit, but those which were not 
so treated never did so, although their own pollen was pushed 
into the stigma by the incurving of the column. 
I compared with this the action in the allied genus Cymbidum. 
In an unfertilized flower of C. aloifolium, Sw., the column 
merely withers up and does not alter at all; but on fertiliza- 
tion a rapid change takes place. The column increases to 
double its width—from 44 mm. to 9 mm., and at the same 
time shortens about 2mm. The part that enlarges is chiefly 
the front wall (venter). The whole length of the column is 
thus modified, and not merely the upper part, as in Gram- 
matophyllum. 
In the latter orchid cross-fertilization is absolutely necessary, 
and that within a few days after the flower opens. Accidental 
self-impregnation destroys the flower by setting up at once the 
growth of the column, which almost immediately prevents any 
possibility of any cross-fertilization by covering the stigma, 
and is itself incapable of producing fertilization. The advan- 
tage of the incurving of the column after fertilization is 
obvious ; for if, as often happens, the pollinia are not placed 
exactly on the stigmatic surface, the apex of the column forces 
them well into the stigma and covers them up init. At the 
Same time, the action in the unfertilized plant is absolutely 
injurious, for thereby the flower is rendered unable to set seed 
long before it is withered. 
In Cymbidium, on the other hand, this action only com- 
mences on impregnation, so that the flower is fertilizable till 
LINN. JOURN.—BOTANY, VOL. XXXII. Z 
