72 INDEX TO AMERICAN BOTANICAL LITERATURE 
Parish, S. B. A supplementary bibliography of the Southern 
California flora. Bull. S. California Acad. Sci. 19: 24-29. 
a 1920. 
Pearson, W. H. Notes on a small collection of hepatics from 
Oregon. Bryologist 24: 21. 25 Jl Ig2t. 
Piper, C. V. A new genus of Leguminosae. Jour. Washington 
Acad. Sci. 10: 432,433. 19 S 1920. 
Monoplegma, gen. nov., from Costa Rica. 
Pittier, H. Inophloeum, a new genus of the mulberry family. 
Jour. Washington Acad. Sci. 6: 112-114. 4 Mr 1916. 
From Panama and adjacent Colombia. 
Pittier, H. Notes on the genus Swartzia in Panama and 
Guatemala. Jour. Washington Acad. Sci. 11: 155-160. 
4 Ap 1921 
Includes 2 new species. 
Pittier, H. On the origin of chicle with descriptions of two 
new species of Achras. Jour. Washington Acad. Sci. 9: 
431-438. 19 S 1919. 
New species from Guatemala and Panama. 
Pittier, H. Two new species of Bursera. Jour. Washington 
Acad. Sci. 11: 229, 230. 19 My 1921. 
From Panama and Guatemala. 
Pittier, H. The Venezuelan mahogany, a hitherto undescribed 
species of the genus Swietenia. Jour. Washington Acad. 
sci. 10: 32-34. 19 Ja 1020, 
Swittenia Candollet, sp. nov. 
Pritchard, F. J. Relation of horse nettle (Solanum carolinense) 
to leafspot of tomato (Septoria may aoe Jour. Agr. 
Research 21: 501-506. pl. 95-99. 1 Jl 19 
Ramaley, F. The role of sedges in some a plant 
communities. Am. Jour. Bot. 6: 120-130. fia, 2. Mr 191s. 
Richards, B. L. Pathogenicity of Corticium vagum on the 
potato as affected by soil temperature. Jour. Agr. Research 
21: 459-482: pl. 88-93. 1 Jl 1921. 
Ricker, P. L. A sketch of botanical activity in the District 
of Columbia and vicinity. Jour. Washington Acad. Sci. 
8: 487-498. 19 Au 1918; 516-521. 19 S. 1018. 
Ricker, P. L. A synopsis of the Chinese and Formosan species 
of Albizzia. Jour. Washington Acad. Sci. 8: 242-246. 19 
Ap 1918. 
