222 EXPERIMENT STATION RECORD, [Vol. 43 



AGRICULTURAL BOTANY. 



Notes on trees and shrubs in the vicinity of Washington, W. W. Ashe 

 (Bui. Torrey Bot. Club, 46 {1919}, No. 6, pp. 221-226).— The author has found 

 within the vicinity of Washington, D. C, a number of trees and shrubs which 

 do not appear to have been recorded previously. The forms regarded as new 

 species are named Amelanchier sera and A. micropetala; the new variety is 

 A. micropetala potomacensis ; and the new combinations proposed are A. 

 canadensis inteiinedia and Carya glabra hirsuta. 



New and old species of Opuntia, D. Griffiths {Bui. Torrey Bot. Club, 4S 

 {1919), No. 6, pp. 195-206, pis. 2). — Tlie author here records facts obtained in the 

 study of Opuntia spp. on the U. S. Department of Agriculture grounds at 

 Chico, Cal. Of species wliicli have long been under observation, eight are 

 described for the first time, and two gre recognized for the first time since 

 originally described. 



New species of Uredineaj, XI, J. C. Akthue {Bui. Torrey Bot. Club, ^6 

 {1919), No. 4, PP- 107-125). — Since the issuance of the preceding number of tliis 

 series (E. S. R., 40, p. 327), two errors have been corrected and are pointed 

 out herein. A number of grass rasts are provisionally transferred. 



The wholly new species lierein proposed, about 16 in all, are taken from 

 recent collections or more largely from herbarium material, partly from the 

 Northern States, but more largely from the southern part of the United States, 

 from Mexico, and from the West Indies. 



The ancestry of maize. — A reply to criticism, P. Weatherwas {BuU 

 Torrey Bot. Club, 46 {1919), No. 7, pp. 27 5-27 S).— This is mainly a reply to 

 Kempton (E. S. R., 41, p. 727). It is held that comparative morphology, which 

 has been one of the most reliable and productive agents in establishing lasting 

 theories of evolution, points out reasonable evidence of the direct origin of Zea, 

 co®rdinately with Euchlsena and Tripsacum, from an ancestor long ago extinct. 

 The three genera are thought to be different simply because they have lost 

 different organs that were possessed by their progenitor and have specialized 

 others to different degrees. 



The pure line hypothesis and the inheritance of small variations, E. Wab- 

 KEN {So. African Jour. Sci., 15 {1919), No. 7, pp. 535-567, pi. i).— Following a 

 brief discussion of certain aspects of Mendelism, an account is given of experi- 

 mentation carried out to ascertain whether small casual variations can be 

 inherited. This work, consisting in breeding experiments wtih nasturtiums 

 {Tropceolum minus and T. ma jus), is detailed and tabulated with discussion, 

 as are the results. 



The main result of this investigation is to show that the so-called factors of 

 the germ cell are variable in nature and are thus transmitted. 



Half mutations and mass mutations, H. de Vries {Ber. Deut. Bot. GeselUf 

 36 {1918), No. 4, pp. 193-198). — The author considers that his studies and obser- 

 vations show that mass mutations and half mutations play a very prominent 

 part in the production of new forms among plants, both in a state of nature 

 and under cultivation. 



A petunia hybrid, H. Rasmuson {Bot. Notiser, No. 6 {1918), pp. 287-294).^ 

 As a result of studies carried out with hybrids of Petunia nyctaginiflora and 

 P. violacea, the author states that the deeper colors were dominant over the 

 lighter, and that blue anther coloration was dominant over yellow. The factors 

 for deep flower coloration and blue anther coloration are inherited independ- 

 ently. 



