434 
POPULAE SCIENCE EEVIEW. 
part from this plan ; that He therefore made the same organ to perform 
diverse functions (often of trifling importance compared with their proper func- 
tion), converted other organs into mere purposeless rudiments, and arranged 
all as if they had to stand separate, and then made them cohere ? Is it not 
a more simple and inteUigihle view that all Orchids owe what they have in 
common to descent from some mono-cotyledonous plant, which, like so many 
other plants of the same division, possessed fifteen organs, arranged alternately, 
three within three, in five whorls, and that the now wonderfully changed 
structure of the flower is due to a long course of slow modification ; each 
modification having been preserved which was useful to each plant during 
the incessant changes to which the organic and the inorganic world has been 
exposed ? 
Our space will onlj permit us to indicate that whilst deduc- 
tions are made in favour of the theory of natural selection/^ 
the culminating and special deduction of the work is — that 
throughout this vast order^ containing, probably, about six 
thousand species, the act of fertilization is almost entirely 
left to insects ; that self-fertihzation is a rare event ; and 
that, herein, Nature tells us, in the most emphatic manner, 
that she abhors perpetual self-fertilization/^ 
Finally, we must briefly allude to Mr. Darwin^s discoveries 
on the fertihzation of the Purple Loosestrife. Until recently it 
was supposed that the relative lengths and characters of the 
stamens and pistils were approximately permanent in each 
vegetable species ; that, in a certain plant which had the 
pistil extending beyond the stamens, it might be predicated 
that in all the flowers of the same species the pistil would be 
found longer than the stamens and similar in all other respects. 
Such, however, is not the case. Plants with two forms were 
discovered, and, at length, Mr. Darwin announced to the 
Linnean Society that he had found a plant in which three 
forms existed ; this was the common purple loosestrife, Lytlirum 
Salicaria. This, however, is only part of the truth, the whole 
being’ still more marvellous. In the three forms, all of which 
contain male and female organs, there are three distinct female 
and three sets of male organs or stamens, all difiering from 
each other as much as in ordinarily distinct species ; and all 
three forms must necessarily co-exist for the orgaciization of 
the species to be perfect. 
In the accompanying figures (fig. 10) a represents the long- 
styled, h the mid-styled, and c the short-styled forms. In the 
long-styled form the pistil is one-third longer than in the mid- 
styled form and three times as long as that in the short-styled 
form. The stamens are twelve in each form, in two sets, of six in 
each set. In the long-styled form the six longer stamens are 
shorter than the pistil, but extend beyond the mouth of the 
corolla; the six shorter stamens do not reach to the mouth 
