INDEX TO AMERICAN BOTANICAL LITERATURE 217 
Schlechter, R. Beitrage zur Kenntnis der Orchidaceenflora von 
Parana (cont.). Repert. Sp. Nov. Regn. Veg. 16: 316-334. 30 
Ap 1920. 
Includes 17 new species. 
Schlechter, R. Orchidaceae novae et criticae.—Decas LXV. Repert. 
Sp. Nov. Regn. Veg. 16: 353-358. 30 Ap 1920. 
New American species in Habenaria, Prescottia, and Aa. 
Schuchert, C. The evolution of primitive plants from the geologist’s 
viewpoint. .New Phytol. 19: 272-275. 31 Ja 1921. 
Schwappach, A. F. Beitrage zur Kenntnis der Wachtumsleistungen 
von Pseudotsuga Douglasii. Mitt. Deutsch. Dend. Ges. 1920: 
262-269. 1920. 
Schwerin, F. von. Die Formen der Picea pungens. Mitt. Deutsch. 
Dend. Ges. 1920: 231-235. 1920. 
Includes several new American forms. 
Schwerin, F. von. Revisio generis Sambucus. Mitt. Deutsch. Dend. 
Ges. 1920: 194-231. 1920. [Illust.] 
Includes Sambucus Rehderana, sp. nov., from Texas, and several new Anierican’ 
varieties and 
Sears, P. ae Variationin Taraxacum. Science II. 53:189. 25 F 1921. 
Setchell, W. A. Marine algae and terrestrial plants of Tutuila, Samoa. 
Carnegie Inst. Washington Year Book 19: 198, 199. . 3 F 1921. 
Shaw, R. H., & Wright, P.A. A comparative study of the composition 
of the sunflower and corn plants at different stages of growth. 
Jour. Agr. Research 20: 787-793. 15 F 1921. 
Shreve, E. B. Causes of the seasonal changes in the transpiration n of 
Encelia farinosa. Carnegie Inst. Washington Year Book 19: 73-75. 
3 F 1921. 
' Shreve, F. Ecology of the Santa Lucia Mountains [California]. 
‘Carnegie Inst. Washington Year Book 19: 78, 79. 3 F 1921. 
Shreve, F. The vegetation of a desert valley [near Tucson, Arizona]. 
Carnegie Inst. Washington Year Book 19: 77, 7 3 F 1921. 
Shunk, I. V. Notes on the flagellation of the nodule bacteria of 
Leguminosae. Jour. Bact. 6: 239-246. pl. 1. 1921. 
Skottsberg,C. Remarks on Splachnidium rugosum (L.) Grev. Svensk. 
Bot. Tidskr. 14: 271-278. f. I-5.. 1920. 
Speare, A. T. Massospora cicadina Peck. Mycologia 13: 72-82. 
$l. 5, 6. . 26 Mr 1021. 
A fungous parasite of the periodical cicada. 
