314 NOTES AND COMMENTS [NOVEMBER 
plants to their surroundings as a branch of botany worthy the attention 
of teachers and students. 
With the July number the Botanical Gazette enters on a new 
volume (xxvil). The issue contains three important papers. “ Studies 
on Reduction in Plants,’ by G. F. Atkinson, describes the intra-nuclear 
changes occurring during pollen development in an aroid (Arisaema 
triphyllum), and a liliaceous plant (Trillium grandiflorum). The author 
suggests that “some of the bewilderment which now surrounds certain — 
phases of the study of the morphology of the nucleus” will disappear, 
“if we recognise that there is such a thing as a reducing division or 
qualitative reduction in plants as represented by such types as 
Trillium, Arisaema,’ and others; “that there are plants in which only 
a quantitative or numerical reduction occurs,’ as in Podophyllum ; 
“and possibly that there is still another type where in the same plant 
qualitative reduction may take place in some cells, while quantitative 
or numerical reduction only takes place in others.” The paper is fully 
illustrated. Charles Robertson adds another (No. xix.) to his long list 
of papers on “ Flowers and Insects.” He deals chiefly with the flower 
visits of oligotropic bees, those, namely, which restrict their visits for 
pollen-collecting to a few flowers. Oligotropic species are more fre- 
quent than has hitherto been supposed, and the author gives a list 
of fifty-two belonging to thirteen genera, the number of plant species 
visited varying from one to nine. He also discusses the influence 
of bees in the modification of flowers, tracing the origin of pollination 
by insects, and the development of increasingly complex mechanism, 
as the result of insect-visits. 
The “Origin of the Leafy Sporophyte” is a critical contribution by 
Prof. J. M. Coulter, to the much debated question of the development of 
the higher leaf-bearing plant from the moss-capsule or some one or more 
ancestors. The argument from cytology is not yet clear, and the 
author is fain to admit that, on the whole, all such discussion is “ very 
vague and general, and may not commend itself to many as profitable.” 
We have received a separate copy, printed in advance from the 
eleventh annual report of the Missouri Botanical Garden, of a revision 
of the North American species of Huphorbia, belonging to the section 
Tithymalus. Most of our British spurges belong to this section, and 
nearly all of them have been introduced into the United States and 
have become more or less widely spread there. The paper, which is 
by J. B. 8. Norton, is accompanied by no less than forty-two plates 
showing the general habit of the plant, with floral dissections and 
figures of the seeds. We have so often to deplore the absence of 
figures in systematic books and papers that we are glad to note an 
example of a monograph in which every species is figured. 
