-T 



70 BOTANICAL GAZETTE [july 



sugar rather than starch. The author concludes that the excess of sugar 

 causes the appearance of the anthocyan. This conclusion is based upon 

 Overton's experiments. A third paper deals with the distribution of plants 

 on a peculiar formation known as the " Polygonboden." In the last paper 

 the author has collected some miscellaneous floristic notes.— H, N. Whit- 

 ford. 



NOTES FOR STUDENTS. 



R. Knuth® has begun the publication of the results of his study of 

 Geranium, After the general distribution of the genus is presented, each of 

 the twelve sections is considered separately, the present paper including 

 Unguictdata (5 spp.), Siibacaulia (4 spp.), Tuberosa (4 spp.), and Bairachia 

 (38 spp.). — J. M. C. 



In a preliminary papers on chromosome reduction in Larix ieptolepis 

 Ishikawa announces a condition similar to that described in his paper on 

 Allhan fisttilosum. In the prophase of the first division of the pollen mother 

 cell -twelve pairs of chromosomes appear. The chromosomes of the pair may 

 be variously united, sometimes forming tetrads. In the second division 

 twelve ring-shaped chromosomes are formed. The writer interprets the first 

 division as an "equation division," and the second as a "reduction division 

 in Weissman's sense. The full paper will appear in Jour, ColL Set. Tokyo, 



— W. J. G. Land. 



»i 



J, M. Greemman® has published the general results of his long study of 

 the North and Central American species of Senecio, After an historical 

 account of the genus, the morphology of the dififerent plant members is con- 

 sidered, and the classification presented. About 300 species are included, 

 grouped into 22 sections, 14 of which bear Mr. Greenman's name. The sub- 

 genus Euse7tecio O. Hoffm, includes 21 of the sections, and Pseudogynoxts 

 Greenm, the remaining one. The species are merely listed under their tribes, 

 70 of them being unpublished new species. The geographical distribution 

 of the genus as a whole and of each section is presented in concise and tabu- 

 lated form, — J. M. C. 



A NEW INTERPRETATION of the phenomena of sap pressure and bleed- 

 ing has been set forth by Molisch.^ He takes the position that all the cases 



*Uber die geographische Verbreitung and die Anpassungserscheinungen der 

 Gattung Geranium im Verhaltnis zu ihrer systematischen Gliederung. Engler's Bot. 



Jahrb. 32 : 190-208, 1902. 



'Ishikawa, C, Ueber die Chromosomenreduction bei Larix Ieptolepis, Beih. 

 Bot. Centralb. n: 6-7. 1901. 



'Monographie der nord- und centralamerikanischen Arten der Gattung Senecio. 

 Engler's Bot. Jahrb. 32 : I-33. 1902. 



9MOLISCH, Hans, Ueber localen Blutungsdruck und seine Ursachen. Bot. Zeit. 

 60 : 45-63. 1902. 



\r 



