62 WILD FLOWER FAMILIES 
encloses the rounded mass of the spadix, which is 
completely covered by the florets, in which the pis- 
tils mature before the stamens. The pollen is 
shed in great abundance in the closed chamber 
of the spathe, so that it may easily be carried to 
other plants through the visits of insects, though 
evidently it is so protected from the wind that 
there is little likelihood of its being blown from 
plant to plant. 
Many plants call insects to their aid in this 
work of pollen distribution. One would think, 
however, that this early flowering Swamp Cab- 
bage had little chance of such assistance at a 
season when the northern slopes are yet covered 
with snow and the sheltered pools are still filled 
with ice. But the plant has brought about a 
marvellous adaptation to the conditions of its life. 
At this early season certain small flies are abun- 
dant in the situations where the Swamp Cabbage 
grows. They fly about in the early spring sun- 
shine and when the weather is cold and stormy 
they seek such shelter as may be at hand. Now 
the most perfect shelter that these flies can find is 
inside the Swamp Cabbage spathes, which are so 
constructed that neither rain nor wind may enter; 
and, surprising as it may seem, the blossom not 
only furnishes shelter from the elements, but it 
also provides artificial heat. Botanists have 
found that the purple substance of the spathes 
