86 
ANEMOPHILOUS FLOWERS 
characters, evolved entirely in anemophilous plants, or are 
secondary, derived from characters of an entomophilous 
ancestry. The most striking feature is perhaps the absence 
of the entomophilous characters ; the flowers are usually 
inconspicuous (most often without a corolla), scentless and 
honeyless, and have rarely any tube-formation or irregularity. 
The chief positive characters are an abundance of freely 
exposed powdery pollen, and large stigmas to catch it. 
An abundance of pollen, to compensate for the enormous waste in 
transport, is a prime necessity. This in the existing Gymnosperms and 
catkinate orders, is effected by the presence of a great number of 
stamens; in Gramineae, Cyperaceae, Potamogeton, Empetrum, Littorella, 
Urticaceae, &c. there are few stamens, but very large anthers; in 
Ricinus the stamens are branched (this is distinctly a recently acquired 
character, for it is not found in others of the order). The stamens all 
ripen at the same time, instead of successively as in entomophilous 
flowers (see Thalictrum). The pollen is dry and incoherent so that it 
blows about easily. It must be as far as possible protected from rain ; 
in most cases this is partly effected by the fact that the anthers only 
open in dry air ; in the catkins the bract forms a pent-house over the 
stamens, in Urticaceae the stamens are folded inwards until the moment 
of dehiscence, in Gramineae they are protected by the glumes and only 
emerge from them in dry air, and so on. The pollen must be freely 
accessible to the wind ; in the catkin orders, Platanus, &c. the pendulous 
inflorescence is easily moved by wind, and the pollen, which often 
collects on the upper surfaces of the bracts, is shaken out. In the 
flowers with few stamens, the filaments are usually long and projecting, 
the anthers usually versatile. In Grasses, &c. the stamens are pendu- 
lous, the flower itself in Rumex. In Urticaceae the pollen is expelled 
from the anthers by an explosion. In the gynoeceum, most anemo- 
philous flowers have large bush-like stigmas, much larger and rougher 
than those of entomophilous flowers, and freely exposed so as to have 
the best chance of catching the floating pollen grains. The most 
remarkable is perhaps the stigma of Zea. Many, e.g. the catkin 
families, flower before the leaves appear ; others, e.g. Grasses, &c., 
have the inflorescence well above the vegetative shoot, and are often 
of social habit. Both these facts tend to economical pollination. The 
number of ovules is generally very small, often only one. This may be 
correlated with the fact that there is little chance of sufficient pollen 
reaching the stigma to fertilise many ovules, whereas in entomophilous 
flowers the pollen clings together in masses. The most notable 
exceptions are Juncus and Populus. Dichogamy (see below) is 
common in anemophilous flowers, and, for some unknown reason, it 
is nearly always protogynous. For further details see the orders and 
genera mentioned, also Sparganium, Triglochin, Ulmaceae, Elaeag- 
naceae, ike. 
