3 i4 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 (xxviii). The issue contains three important papers. " Studies 

 on Reduction in Plants," by G-. F. Atkinson, describes the intra-nuclear 

 changes occurring daring pollen development in an aroid (Arisaema 

 trvphyllum), and a liliaceous plant {Trillium grandifiorum). 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 Eobertson 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 Euphorbia, belonging to the section 

 Tithymcdus. 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. S. 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. 



