Bliithendiagramme, ‘The account of the various kinds of inflores- 
cence in’Chap. V. elucidates a very difficult subject. In the doctrine 
of the flower, Chap. VL., it is stated that “ extended observation leads 
to the conclusion that the typical flower in nature has two 
series in the perianth, or is Diplosteminous, the stamen circles alternat- 
ing respectively with calyx and corolla. The terms Antisepalous and 
Antipetalous proposed for such stamens .are so much better than 
episepalous and epipetalous that we may reasonably look for their 
general adoption. This chapter is full of interesting discussions of 
different points in floral irregularity, and of the adaptations for fertil- 
ization. 
Chapter IX., Zaxonomy, treats first of the vegetable individual 
and secondly of the idea of species. In regard to the former, the 
conclusion is: “ Upon the view here adopted, that plants do not 
rise high enough in the scale of being to reach true individuality, 
the question is not whether it is the cell, the phytomer, the shoot, 
the tree, or the whole vegetative product of a seed which answers to 
the animal individual, but only which is most analogous to it. In 
our view, its analogue is the cell in the lowest grades of vegetable 
life, the phytomer [plant part=node] in the higher. But, in botanical 
description and classification, by the individual is meant the herb, 
shrub, or tree, unless otherwise specified.” 
As the elusive idea of species underlies the whole question of 
classification and evolution, we shall endeavor to present Dr. Gray’s 
views, though probably our disconnected quotation may fail to do 
him justice. He says: “ Among the many definitions, that of A. L. 
Jussieu is one of the briefest and best, since it expresses the funda- 
mental conception of a species, 7. ¢., the perennial succession of sim- 
ilar individuals perpetuated by generation.” “The two elements of 
species are : 1. Community of origin; and 2. Similarity of the com. 
_ ponent individuals. But the degree of similarity is variable, and the 
fact of genetic relationship can seldom be established by observation 
or historical evidence. It is from the likeness that the naturalist 
ordinarily decides that such and such individuals belong to one spe- | 
cies. Still the likeness is a consequence of the genetic relationship ; 
so that the latter is the real foundation of species.” p. 317. Speak- 
ing of Subspecies: “We judge them not to be so many species, 
either, because in the case of cultivated races we know something of 
their origin or history, and more of the grave changes which long 
domestication may bring to pass; or because the forms, however. 
stable, differ among themselves less than recognized species gener- 
ally do; or because very stfiking differences in the extremes are 
connected by intermediate forms. And our conclusions, it must be 
understood, are not facts, but judgments, and largely fallible judg- 
ments. For while some varieties appear strikingly different, some 
species are very much alike.” p. 320. Referring to the remarkable 
reversion of the hybrids of Datura: “ There appears, therefore, to 
be a real ground in nature for species, notwithstanding the difficulty 
and impossibility in many cases of defining and limiting them.”’ p. 
322. “All plants of the same species are so much alike that they 
_ are inferred to have descended from a common stock, and their dif- 
