October 20, 1905.] 



SCIENCE. 



507 



lowed by twelve chapters (184 pages) on 

 ' Vegetation in Relation to Environment.' 

 Seventy-five pages (9 chapters) are given to 

 the structure and classification of angio- 

 sperms. A useful appendix contains sugges- 

 tions as to the collection of material, the selec- 

 tion of apparatus, reagents, reference books, 

 etc. One has but to note the space given to 

 the subdivisions of the science to realize the 

 change which has taken place in our concep- 

 tion of its scope, and the relative importance 

 of its departments. Roughly speaking, 20 

 per cent, of the book is given to physiology, 

 30 per cent, to morphology, 40 per cent, to ecol- 

 ogy and biit about 10 per cent, to classification. 

 The college student who successfully covers 

 the subject as presented in this book will have 

 a very good introduction to the several depart- 

 ments of the science. 



The general decapitalization of generic 

 names when used alone strikes one rather 

 oddly, as when we find spirogyra, vaucheria, 

 uncinula, rhabdonia, riccia, marchantia, etc. 

 Even family names may suffer decapitaliza- 

 tion, as ' graminese ' (p. 658). 



KARSTEN AND SCHENCK's VEGETATIONSBILDER. 



Quite recently several more fascicles of 

 this admirable publication of photographs of 

 vegetation have been received from the iDub- 

 lisher, Grustav Fischer, of Jena. As in the 

 earlier fascicles noticed in Science for April 

 7, 1905, each of these contains six fine repro- 

 ductions of photographs accompanied by full 

 explanatory text. Thus fascicle 1, of Series 

 III., contains six photographs by E. Ule of 

 ant nests (Blumengiirten) in Brazilian vegeta- 

 tion ; fascicle 2, six photographs by Dr. E. A. 

 Bessey, of vegetation in Russian Turkestan 

 (1, moving sand dunes on the Amu Daria 

 River; 2, sand dunes held by Calligonum, 

 Salsola, and Taraarix; 3, Tamarix laxa and 

 Salsola arhuscula; 4, Haloxylon ammodendron 

 and Salsola arhuscula; 5, Calligonum arhor- 

 escens; 6, Cuscuta engelmanni on a quince 

 tree). The third fascicle is by Dr. M. Busgen, 

 Dr. H. Jensen and Dr. W. Busse, and includes 

 photographs of vegetation in middle and east- 

 ern Java. Of these the most striking are 

 those of the teak and bamboo forests. The 



low price of these beautiful plates (2.50 Marks 

 per fascicle) should enable every botanist to 

 own a complete set. 



FURTHER PLANT CELL STUDIES. 



Several months ago (July 7, 1905) parts I. 

 to IV. of Dr. B. M. Davis's ' Studies on the 

 Plant Cell ' were noticed in these columns. 

 Since that notice was written two more parts 

 have appeared (American Naturalist, July 

 and August). They are devoted to a dis- 

 cussion of cell activities at critical periods of 

 ontogeny in plants, which are taken up under 

 several heads : (1) Gametogenesis (in which 

 we find the suggestion that ' the most satis- 

 factory theory of the origin of sex in plants 

 regards primitive gametes as weaker or lack- 

 ing in the potentialities of vegetative growth, 

 and conjugation as a mutually cooperative 

 process resulting in a rejuvenescence of the 

 protoplasm ') ; (2) fertilization (in which the 

 author suggests a narrower conception of the 

 act, by excluding ' vegetative fertilization ') ; 

 (3) sporogenesis ; (4),.redu.ction of the chromo- 

 somes (in which much new matter is here in- 

 corporated in a concise statement) ; (5) 

 apogamy (under which he discusses partheno- 

 genesis) ; (6) apospory; (7) hybridization (in 

 which we find this significant sentence — " the 

 phenomenon of hybridization is far too com- 

 plex to be explained in terms of simple ratios, 

 and while some characters may be paired or 

 correlated in proportions that can be expressed 

 by mathematical formiilse, there is little prob- 

 • ability that the assemblage of characters which 

 make species can be so definitely grouped as 

 the strongest disciples of Mendel may hope ") ; 

 (8) xenia (' the immediate or direct effect of 

 pollen on the character of seeds and fruits'). 

 Under the last title it is stated that ' the best 

 understood examples of xenia are found in the 

 hybrids of maize.' The whole discussion in 

 these two parts covers ninety-six pages, and 

 includes a bibliography of 152 titles. 



A STUDY OF INSECT GALLS. 



Db. M. T. Cook, now of the Agricultural 

 Experiment Station at Santiago de las Vegas, 

 Cuba, has brought together in orderly form 

 what is known as to the Indiana plant galls 



