INDEX TO AMERICAN BOTANICAL LITERATURE 79 
Sax, K., & Gowen, J. W. Permanence of tree performance in a 
clonal variety and a critique of the theory of bud mutation. 
Genetics 8: 179-211. My 1923. 
Schaffner, J. H. Observations on the sexual state of various 
plants. Ohio Jour. Sci. 23: 149-159. Je 1923. 
Schmitz, H. Notes on wood decay—I. The wood destroying 
properties of Polyporus volvatus. Jour. For. 21: 502, 503. 
y 1923. 
Schulz, O. E. Cruciferae—Brassiceae (pars2). Pflanzenreich 
IV 105: I- 100. f. 1-26. 26 Je 1923. 
Schulz, O. E. Erythroxylaceae, in Pilger, R., Plantae Liitzel- 
bergianae brasilienses. Notizbl. Bot. Gart. u. Mus. Berlin- 
Dahlem 8: 426, 427. 15 Je 1923. 
Includes Erythroxylon Arrojadot, sp. nov., from Brazil. 
Setchell, W. A. Parasitic Florideae, Il. Univ. California 
Publ. Bot. 10: 393-396. 24 My 1923. 
Includes 3 new genera and 7 new species from California. 
Setchell, W. A. A revision of the west North American species 
of Callophyllis.. Univ. California Publ. Bot. 10: 397-402. 
24 My 1923. 
Includes 14 new species. 
Shear, C. L. Life histories and undescribed genera and species 
of Fungi. Mycologia 15: 120-131. pl. 12, 13 + f. I-7. 
31 My 1923. 
Includes 3 new genera and 3 new species. 
Shedd,O.M. Effect of adsorption and other factors on certain 
plant food constituents obtained in the dilute nitric acid 
digestion of soils and animprovement for their estimation. 
Soil Sci. 15: 383-394. My 1923. 
Shull, C. A., & Davis, W.B. Delayed germination and catalase 
activityin Xanthium. Bot.Gaz.75:268-281. 19My1923. 
Shull, G. H. The species concept from the point of view of a 
geneticist. Am. Jour. Bot. 10: 219-228. 10 My 1923. 
Sim, R. J. Observations on the climbing fern in Pennsylvania. 
Am. Fern Jour. 13: 40-42. 11 My 1923. 
