FLOWERS AND INSECTS 251 
flower the stamens are short and included in the tube, 
while the style is long and projecting, with the four stig- 
matic lobes exposed well above the corolla (Fig. 246, A). 
Fie. 246.—Flowers of Houstonia: A, form with short stamens and long style; B, 
form with long stamens and short style-—After Gray. 
In the other flower the relative lengths are exactly reversed, 
the style being short and included in the tube, and the 
stamens long and projecting (Fig. 246, B). It appears 
that the pollen from the short stamens is more effective 
upon the short style; and that the pollen from the long 
stamens is more effective upon the long style. The body 
of the visiting insect fills the corolla tube and projects 
above it. In visiting flowers of both kinds, one region of 
the body receives pollen from the short stamens, and 
another region from the long stamens. In this way the 
insect is soon carrying about two bands of pollen, which 
come in contact with corresponding stigmas. 
