FERTILIZATION OF FLOWERS BY INSECTS. 275 
the visits of insects should offer a much greater variety of floral 
forms than plants adapted to the wind. 
These two propositions which are necessary consequences of the 
Darwinian doctrine are effectually confirmed by observation, for 
ariemophilous flowers are not only less numerous than entomophi- 
lous,* but are also much less varied in their conformation. 
The transfer of pollen by means of the wind demands thaf the 
anthers and stigmas be well exposed to the air, and it is also 
necessary for the pollen to be subtile and very light and dry, so as 
to be more easily carried by the air, and to be produced in enor- 
mous quantities so as to insure fixing upon the stigmas some one of 
its grains. Remarkable examples of such a disposition are afforded 
by the Cupuliferse, Coniferæ, Graminaces, Juncacer and Plantagi- 
nacer.t If, for example, a bush of hazel in flower is shaken, or if 
* If we think of the i 1 ti 
ophilous families of the enia Amentaceæ, Gra rami naceæ, Sheen er te “Junca- 
cex, and of the great number of flowers which gang individual of ‘inal ust. bears, 
the statement that anemophilous flowers are less numerous than aragna ia is 
pn to dispute 
yapapi however, the POE maintained by Müller is most just; and the only 
change w) s to substantiate er his kap sate other; anoppi: 
lous ii h less numerot 
their flowers than entom ophi ilous i li 
explains why in cold countries where the generation of insects is opposed by the cli- 
mate, the whole of = vegetation i is compose mni v Aer and gregarious plants 
(firs, birches, Grami 4 erefore devii i onotonous and 
poor in form; while in warm countr rie’ where m piee of insects abound, vegetation is 
most rich in diversity of forms and therefore composed of species not gregarious but 
ilous 
t The genus Plantajo furnished me a most interesting subject of stady, since x ex- 
amining some of it how by g 
can change to an entomophilou 
Plantago b as far as f could observe, develops i in three forms. One of these 
as a t with which are quite broad and tre 
ble in the wind, ikabit niondiowe mai is exclusively anemophilous, as I have never 
seen it visited ‘byt insects. p 
in the first. t il I saw, how wever, occasi ionally a a spe- 
cies of Halictus light upon its spikes and ty to gather the pollen; but the structure of 
` the flower is so ill-adapted to such a purpose that the greater part of the pollen fell 
to the earth h without being of use either to the insect or ‘the plant. The third form is of 
small size. t, and the filaments shorter than 
in the others. In the he pastures 1 upon th je Ajpeniitnies of Chiavari I saw a great number of 
boss fiying diligently from one spike to ya ome pollen with perfect success 
p e Oran the plants. There 
is, therefore, a form of Plant fectl t E 
mophilous forms, and equally apani o of f veing! fecundated by the wind or bees. 
Now if we suppose to become rigid and co. colored, the pollen 
unctuous and sticky, and the proline to Yoon" their special tremulousness, we erar 
witness the formation of an entomophilous from an anemophilous species. Eeay 
AMER. NATURALIST, VOL. V. 18 
