April 14, 1899.] 



SCIENCE. 



549 



Botanical Garden) a rich mass of materials, he 

 set himself to the task of making a complete 

 monograph of the tribe, accompanying it with 

 such a collection of plates as would throw as 

 much light as possible upon the limits of genera 

 and species understood by him. After nearly 

 two years of delay the volume has appeared, 

 and it is all that the friends of the author an- 

 ticipated, and more too. It is a beautifully 

 printed quarto volume of 22.3 pages and one 

 hundred and twelve finely executed plates. 



In discussing the relationship of the tribe 

 Dr. Rydberg regards it as representing the 

 lowest or primitive type of the family Rosaceae, 

 and from it arose, as separate, divergent groups, 

 the tribes Dryadeae, RubeaeandSanguisorbeae, 

 while from the latter arose the Roseae (with 

 possible relationship to the Dryadeae). On 

 the other hand, from Dryadeae arose the Cerco- 

 carpae and Spireae, and from the latter are de- 

 rived by divergent development the families Po- 

 meae, Drupaceae and Saxifragaceae. In regard 

 to other relationships the author says: ' ' It is evi- 

 dent that the Ranunculaceae and Rosaceae are 

 very nearly related, ' ' and in his diagram showing 

 the foregoing relationships places the Ranuncu- 

 laceae immediately below the Potentilleae. 



Thirteen genera are recognized in the Poten- 

 tilleae, of which the largest is Potentilla with 

 107 species. The next in point of numbers is 

 Sorkelia with 47 species, followed by Fragaria 

 with 20, and Drymocallis with 13. Quite nat- 

 urally, the author found it necessary to describe 

 many new species, and occasionally to give a 

 new name to an old species, because of the 

 preoccupation of the old name. He has been 

 rather conservative in this part of his work, for 

 which he deserves our thanks. In Fragaria the 

 new species are as follows : F. crinita, F. sibbal- 

 difolia, F. truncata,' F. platypetala, F. prolifica, F. 

 pumila, F. ierrae novae, F. pauciflora andP. firma. 

 In the much larger genus, Potentilla, there are 

 but nine new species, but this is due to the fact 

 that Dr. Rydberg, in his work upon this genus, 

 published many new species a couple of years 

 ago in the Bulletin of the Torrey Botanical Club. 

 A most interesting table closes the text, giving 

 data as to the distribution of the Potentilleae in 

 North America. From this we learn that in 

 California there are 64 species, in the Rocky 



Mountains 61, in Oregon and Washington .53, 

 Saskatchewan Region 29, Canadian Rocky 

 Mountains 28, Texas and Arizona 27, the Great 

 Plains 26, New England and Middle States 26, 

 Great Basin 2.3, British Columbia 22, southern 

 Mexico 19, Labrador and Baffin's Bay 17, 

 the Prairie Region 17, Canada 16, Alaska 16, 

 Greenland 15, Arctic Coast 12, Southern States 

 8, northern Mexico 8, Lower California 7, Cen- 

 tral America 2. 



This monograph must at once become au- 

 thoritative for this gi'oup of plants, and to every 

 working botanist dealing with the higher seed- 

 bearing plants it will be indispensable. 



Chaeles E. Bessey. 



The University of Nebraska. 



SCIENTIFIC JOURNALS AND ARTICLES. 



Terrestrial Magnetism and Atmospheric Elec- 

 tricity for March. — The promised series of por- 

 traits of eminent magneticians and electricians 

 is begun in the present number with that of 

 Professor Arthur W. Riicker, the President of 

 the Permanent Committee on Terrestrial Mag- 

 netism and Atmospheric Electricity of the In- 

 ternational Meteorological Conference. The 

 journal has been enlarged to 72 pages, the 

 present number being also freely illustrated 

 and containing several important contributions 

 by eminent investigators, as will appear from 

 the table of contents : 



Aimantation Induite par le Champ Terresbre sur 

 les Aimants, E. Mascart. 



Is there a 428- Day Period in Terrestrial Magnet- 

 ism ? J. F. Hayford. 



Beobachtungen iiber die Eigenelectrieitat der At- 

 mospharisohen Niederscblage, J. Elsterand H. Geitel. 



The Physical Decomposition of the Earth's Perma- 

 manent Magnetic Field — No. 1. The Assumed Nor- 

 mal Magnetization and the Characteristics of the 

 Resulting Residual Field, L. A. Bauer. 



Is the Principal Source of the Secular Variation of 

 the Earth's Magnetism -within or without the Earth's 

 Crust? L. A. Bauer. 



Tafeln zur Geniiherten Auswertung von Kugel- 

 functionen und ihren Diii'erentialquotienten, Ad. 

 Schmidt (Gotha). 



Erdmaguetiscbe Beobachtungen imXJmanaks Fiord 

 (Nordwest-Gronland), 1892-93, H. Stade. 



Abstracts and Reviews. 



Notes : Biographical Sketch of Professor Riicker. 

 Activity in Magnetic Work. 



