362 THE AMERICAN NATURALIST. [Vor. XXXIV. 
I. PorriNATION. 
The flowers of the Iris have long been known to be entirely 
dependent on insects for the transference of their pollen. The 
structure of the flower has so 
often been described, there is 
no need of describing it again ; 
if the reader has forgotten, he 
may refresh his memory by 
reference to the accompanying 
figures. He will recall a flower 
divided into three parts, requir- 
ing three separate visits by the 
insect which would obtain its 
stores; in each part an ex- 
trorse anther placed with its 
back against an overarching 
branch of the extremely large, 
three-parted style (Fig. 1, K); 
below anther and style a passage- 
way to the nectary, with the 
usual guide streaks at its en- 
trance, is formed by the chan- 
neled sepal. The stigma is 
restricted to the upper surface 
of an inferior, transverse, flap- 
like appendage of the style 
branch, just beyond the apex of 
the anther (Fig. 2). This flap 
is very thin and remains ap- 
pressed to the style, with its 
free border toward the entrance, 
the stigmatic surface covered. 
The pollen-laden back of an 
'* entering insect, rubbing against 
it, readily everts the flap and 
The arrow indicates the position deposits pollen on the stigmatic 
on the proboscis ofap z 
surface. Released, it closes 
