OF FLOWERING PLANTS. 71 
for 1862. Robert Brown long since called attention to 
insect agency, in the fertilization of the Milkweed family. 
Almost any summer day we may repeat his observations 
for ourselves. So adhesive are the glands of the Ascle- 
pias obtusifolia (Wavey-leaved Milkweed), that we often 
find honey bees unable either to withdraw the packets, or 
loose their feet from the gland, and thus they become 
prisoners for life. 
There exists yet another class of dimorphic flowers, in 
which we find the large and more conspicuous flowers less 
fertile than those of the other form, which are arrested in 
their development, and are fertilized in the bud. Hugo 
van Mohl has of late called especial attention to them. 
Such flowers have been happily termed precociously fer- 
tilized. Mohl concludes, after close examination of Viola, 
Oxalis, Specularia and Impatiens, that nature is here 
specially solicitous to secure close breeding, or that each 
flower shall be fertilized by its own pollen. “ He calls 
attention also to the fact, that in the large anthers of the 
smaller form of Oxalis acetosella, not more than two 
dozen pollen grains are found, while in the anthers of the 
larger form they are much more numerous. In the smaller 
saa however, the few grains are made more potent, 
and the exercise of their function is secured, by being 
placed in contact with the stigma. It results, ee 
gl! Sectors RIO a a 
ler, under the rep f accurate piv eatisce- 
tors, and that, what was supposed to To a special adapta- 
tion to secure close fertilization, i is, after all, but a more 
nicely conceived method of | an opposite result. 
For exam 2, We were faruerly cant that the interior 
petals of Co dalis clasped thé anthers and stigma of the 
flower in so tight an embrace that outside fertilization 
