50 INDEX TO AMERICAN BOTANICAL LITERATURE 
Rickett, H.W. Regeneration in Sphaerocarpos Donnellit. Bull. Torrey 
Club 47: 347-357. f. 7-25. 5 O 1920. 
Riddle, L. W. Lichens, in Britton, N. L., The Bahama Flora 522-553. 
26 Je 1920. 
Includes 19 new species. 
Roberts, R. H. Off-year apple bearing and apple spur growth. Agr. 
Exp. Sta. Univ. Wisconsin Bull. 317: 3-34. f. 1-13. Jl 1920. 
Robbins, W. J., & Massey, A. B. The effect of certain environmental 
conditions on the rate of destruction of vanillin by a soil bacterium. 
Soil. Sci. 10: 237-246. f..7.. S. 1920. 
Rock, J. F. The leguminous plants of Hawaii. Honolulu, Hawaii. 
i-x + 1-234. Jl 1920. 
Rolfe, R. A. Pleurothallis grandis.. Bot. Mag. pl. 8853. S 1920. 
Rosenbaum, J. A M acrosporium foot-rot of tomato. Phytopathology 
10: 415-422. f. I-g. 1920. 
Rumbold, C. Giving medicine to trees. Sci. Am. Mo. 2: 114-116. 
O 1920. 
Rusk, H. M. The effect of zinc sulphate on protoplasmic streaming. 
Bull. Torrey Club 47: 425-431. f. 1-2. 200 1920. 
Sando, C. E. The process of ripening in the tomato, considered espe- 
cially from the commercial standpoint. U.S. Dept. Agr. Bull. 
359; 1-35. fk 2~¢q + f. 1-9. 7S 4020. : 
Saunders, E. R. Multiple allelomorphs and limiting factors in the 
stock (Matthiola incana). Jour. Gen. 10: 149-178. pl. 7-8 + f. I-3. 
20 Au 1920. 
Schlechter, R. Die Columelliaceae. ‘Notizbl. Bot. Gart. und Mus. 
Berlin-Dahlem. 7: 352-358. 15 Ja 1920. 
Includes 2 new Andine species of Columellia. 
Schlechter, R. Orchidaceae novae, in caldariis Horti Dahlemensais 
cultae. Notizbl. Bot. Gart. und Mus. Berlin- paren 7: 268-280. 
1 O 1918; II. 7: 323-330. 15 My 1919. 
Includes American species of Masdevallia (1), Stelis (6), Pleurothallis (7), Octo- 
meria (3), hei ages a (1), Bulbophyllum (1), Promenaea (2), Capanema (1) 
and Oncidium 
Schlechter, -: Uber eine neue Stanhopea-Art. Notizbl. Bot. Gard. 
und Mus. Berlin- ae 6: 483-484, 15 Ja 1917. 
Stanhopea minor from B: 
ey R. ecules einer systematischen Neuordnung der Spiran- 
_ thinae. Beih. Bot. Centralbl. 37: 317-454. 31 Mr 1920. 
~ REN 2 eee and I new species from America. 
