INDEX TO AMERICAN BOTANICAL LITERATURE 431 
Rock, J. F. Cyctandrene Hawaiienses, sect. Crotonocalyces Hillebr. 
Am. Jour. Bot. §: 259-277. pl. 18-23. 21 Je 1918 
Includes 4 new species in Cyriandra. . 
Rose, J. N. Echeveria nodulosa. Addisonia 3: 23. pl. 92. 29 Je 
1918. 
Rose, J. N. Sinningia speciosa. Addisonia 3: 29, 30. pl. 95. 29 Je 
1918. 
Rosenbaum, J., & Ramsey, G. B. Influence of temperature and pre- 
cipitation on the blackleg of potato. Jour. Agr. Research 13: 507— 
513. 3 Je 1918. 
Salmon, S. C., & Fleming, F. L. Relation of the density of cell sap to 
winter hardiness in small grains. Jour. Agr. Research 13: 497-506. 
pl. 53. 3 Je 1918. 
Sampson, H.C. Chemical changes accompanying abscission in Coleus 
Blumei. Bot. Gaz. 66: 32-53. 15 Jl 1918. 
Saunders, A. P. Peony culture in America. Jour. Internat. Gard. 
Club 2: 157-180. Je 1918. [Illust.] 
Sax, K. The inheritance of doubleness in Chelidonium majus Linn: 
Genetics 3: 300-307. My 1918. 
Seifriz, W. Observations on the structure of protoplasm by aid of 
microdissection. Biol. Bull. 34: 307-324. f. 1-3. My _ 1918. 
[Ilust 
Setchell, W. A. Parasitism among the red algae. Proc. Am. Philos. 
Soc. 57: 155-172. 14 Je 1918. 
Shufeldt, R. W. Pitcher-plants—what are they? Am. Forestry 24: 
347-352. f. 2-9. Je 1918. 
Smith, E. F., & Godfrey, G. H. Brown rot of Solanaceae on Ricinus. 
Science II. 48: 42, 43. 12 Jl 1918. 
Stanford, E. E., & Viehoever, A. Chemistry and histology of the 
glands of the cotton plant, with notes on the occurrence of similar 
glands in related plants. Jour. Agr. Research 13: 419-436. pl. 
42-50. 20 My 1918. 
Steil, W. N. Bisporangiate cones of Pinus montana. Bot. Gaz. 66: 
OS. 7: 7." 45 fF 16x68. 
Stevens, H. E. Lightning injury to citrus trees in Florida. Phy- 
topathology 8: 283-285. f. z. 15 Jl 1918. 
Stevens, N. E., & Wilcox, R.B. Further studies of the rots of straw- 
berry fruits. U.S. Dept. Agr. Bull. 686: I-14. 24 Je 1918. 
St. John, H. Spiranthes in Dover, Massachusetts. Rhodora 20: 
FIt—114. 11 Je 1018. 
