492 BOTANICAL GAZETTE {MAY 
following species: Rosa “Silver Moon’’ (a garden hybrid), Dendrobium atro, 
violaceum (New Guinea), Centradenia floribunda (Mexico and Central America), 
Piaropus azureus (Tropical America), Solidago altissima (Eastern United 
States), Pentapterygium serpens (Eastern Himalayan Region), Freylinia 
lanceolata (Southern Africa), Anneslia Tweediei (South America), Crassula 
quadrifida (Cape of Good Hope), Aster cordifolius (Eastern United States and 
Canada).—J. M. C. 
Redwood distribution.—Investigating the factors limiting the distribution 
of Sequoia sempervirens in California, Coopers’ has made measurements of 
rainfall at a considerable number of stations in the Santa Cruz Mountains, and 
has obtained evidence that heavy winter precipitation is necessary for the 
development of redwood forest. He also shows that this rainfall in itself is 
effective only when accompanied by abundant summer fog. In making the 
rainfall studies a type of rain gauge was used that makes possible the sum- 
mation of precipitation for long periods.—Gro. D. FULLER. 
Algae of Devils Lake.—Moore* has published a preliminary list of the 
algae of Devils Lake, North Dakota, the chief point of interest being the alka- 
line character of the water, which has gradually increased with the diminish- 
ing size of the lake. All of the algae in the list were collected during August 
1915, and comprise 47 species (29 Myxophyceae and 18 Chlorophyceae). No 
new genera or species were found, and all of the species were absolutely typi- 
cal, with no indication of any effect of unusual environment.—J. M. C. 
North American Flora.—The third part of volume 21 includes the Allioni- 
ceae (Chenopodiales) by StaNDLEY. He defines 182 species in 26 genera, the 
large genera being Abronia (28), Boerhaavia (25), and Allionia (25). 
new species are only 9 in number, but the author’s name is associated with 71- 
additional species'and with 5 genera.—J. M. 
Soil toxins.—By very simple experiments P1cKERING»® demonstrates the 
effect.of one plant on another through toxins. The simple technique and strik- 
ing nature of the results are such as to suggest that similar experiments be 
introduced into all our laboratories —Gro. D. FULLER. aes 
 & Cooper, W. S., Redwoods, rainfall and fog. Plant World 20:179-189. 1917. 
oorE, Georce T., Algological notes. II. Preliminary list of algae in Devils 
Lake, North Dakota. Ann. Mo. Bot. Gard. 4: 293-303. 1917. 
39 ae SPENCER, The effect of one plant on another. Ann. Botany 31: 
181-187. 1917 : 
