280 FERTILIZATION OF FLOWERS BY INSECTS. 
trine. It has not yet been satisfactorily shown whether or not 
there is any plant subject to a perennial self fecundation (selbst 
befruchtung), that is to say, any plant with hermaphrodite flowers 
where the stigmas are constantly and exclusively fecundated by 
their own anthers. This seems the most simple case, and was 
probably at first general.* 
However it may be with many plants, in the case of the Ranun- 
culaceze, Papaveraceze and Cruciferse, the visits of insects effect 
with greater facility the impollination of the stigmas with the 
pollen of their own flowers (homoclinous or homogamous impollina- 
tion) than the transfer of pollen from one flower to another (hete- 
roclinous impollination). 
Among primordial and homogamous plants every slightest va- 
riation which might open a way to the possibility of the transfer 
of pollen constituted a signal advantage; and therefore the vari- 
ations of color, secretions of honey and viscosity of pollen, became 
fixed in the flower by natural selection. In other and more nu- 
merous cases to these simple dispositions others more complicated 
were added, and of such a nature as not only to favor the eventu- 
ality of heteroclinous fecundation, but render it inevitable and 
necessary. The sexes, for example, began to separate themselves 
as individuals or distinct flowers, as in the genus Salix and the 
* Charles D i the first t jecture that primordial plants wore essentially 
h Į hradit li d that dicli were later and had deyeloped 
- unisexual flowers in obedience to the grand principle e of the division of physiological 
labor. Frederic Hildebrand wane Geschlichter-Vertheilun g bei den Pflanzen. Lips. 
pt 
ence gi ight to my argu- 
ment, but as it is not a suitable place to develop it here, I ion only mention that the 
families of plants received as primordial instance, t phe ying Cycadex, and 
Amentacee are unisexual and a anemophilon PEN r excelle: Aa while those which have 
experienced PTENT evolution. and are. more perfect, tor rogar ance, ry ‘Banunciilacee, 
Leguminose, g e eminently hermaphrodite 
and entomophil 
Diceci oan and n morenoi plants form the primordial group (essentially anemophi- 
lous); anem- 
aiia ‘and atori, and from these again the hermaphrodite plants (essen- 
ny entomophilo 
A Raxmemises with palcontological data; but this important PONES T re- 
f facts and argumen) 
