PHYSIOLOGY. 317 
thargins end ina flat and spear-pointed extremity. 
The pistil is placed in the round cavity of the corol, 
the germen of which is surrounded by six anthers, 
which are shorter than the germen itself. The 
-germen has no style, but is provided with a hexa- 
gonal stigma, which is very shallow, and on its 
upper surface has imbibing pores. ‘The anthers 
cannot empty the pollen upon the stigma, as the 
flower stands always straight upright during the 
period of flowering. ‘The pollen therefore must ne- 
cessarily fall to the bottom of the flower without 
being used, if no insects come near the flower. 
And indeed if it be tried, and all insects kept from 
the flower by a thin, but firmly closed piece of 
yauze, no seeds will be formed. It happens indeed 
not unfrequently, that as it is a particular insect 
which impregnates the flowers, when it is want- 
ing or not able to find the flower, this last withers 
without having a single seed. ‘This insect is the 
Tipula pennicornis. The round bottom of the flower 
is, in its interior, quite smooth, but the tubular 
extremity is lined with dense hair, every one of 
which is turned towards the interior, so as to form 
a kind of funnel, through which the insect may 
very easily enter ; but can with great difficulty only 
return, and is obliged to remain in the cavity.) Um 
easy to be confined in so small a space, it creeps con- 
stantly to and fro, and so deposits the pollen on the 
stigma. After this is done, the flower sinks, the 
hair, which obstructed the passage, shrinks and ad- 
heres closely to the sides of the flower; by which 
means the insect gets free. Who but must admire 
the 
