48 INDEX TO AMERICAN BOTANICAL LITERATURE 
Piper, C. V. Two new legumes from Mexico and Costa Rica. Proc. 
Biol. Soc. Washington 34: 41, 42. 31 Mr 1921 
Phaseolus chiapasanus and Calopogonium ferrugineum sp. nov. 
Pool, R. J., Weaver, J. E., & Jean, F.C. Further studies in the ecotone 
between prairie and woodland. Univ. Nebraska Stud. 18: 1-47. 
Fe taT7 1918. 
Pritchard, F. J., & Porte, W. S. Collar-rot of tomato. Jour. Agr. 
Research 21: 179-184. pl. 41-45. 2 My 1921. 
Includes Verticillium Lycopersici sp. nov. 
Puttemans, A. Gloeosporium Bombacis, n. sp. Bull. Soc. Path. Veg. 
Perch vere. S 1920. 
Puttemans, A. Sur /’Oidium du Chéne au Brésil. Bull. Sec. Path. 
Veg. 7: 37-40. 1 Je 1920. 
Rathbun, A. E. Methods of direct inoculation with damping-off fungi. 
Phytopathology 11: 80-84. f. 1-3. F 1921. 
Record, S. J. Further notes on intercellular canals in dicotyledonous 
woods. Jour. For. 19: 255-266. Mr 1921. 
Reed, H. S. Growth and sap concentration. Jour. Agr. Research 
21: 81-08. f. 1-7. 1 Ap 1921. 
Rehder, A. Azalea or Loiseleuria. Jour. Arnold Arbor. 2: 156-159. 
Ja 19021. 
Rehder, A. Philadelphus verrucosus Schrader spontaneous in IIlinois. 
_ Jour. Arnold Arbor. 2: 153-156. Ja 1921. ; 
Ricalton, J. Famous and interesting: trees. Am. For. 27: 216-224. 
Ap rg2t.  [Illust.] | 
Richards, H. M. Acidity and gas interchange in Cacti. Carnegie 
Instit. Washington Publ. 209: 1-107. f. z-6. 11 Au 1915. 
Riker, A. J. Chondriomes in Chara. Bull. Torrey Club 48: 141-148. 
bl. 3.25 My 1441. 
Rosen, H. R. Furthern observations on a bacterial root and stalk rot 
of field corn. Phytopathology 11: 74-79. f. 1-4. F 1921. 
Roth, G. Die aussereuropdischen Laubmoose. Nachtr.1 [zu Band 1]: 
1-18. pl. 3).2.. 25: Ap: 191a> Nacht. 2: 1-8. oF. 20. tN i0ta: 
Nachtr. 3: 1-6. pl. r. 18 O 1915. 
Rowlee, W. W. Tropical trees with light-weight iat Jour. New 
York Bot. Gard. 22: 75-78. Ap 1921. 
Rusby, H. H. Guide to the Economic Museum of the New York 
Botanical Garden. Bull. New York Bot. Gard. 11: 1-318. 30 Ap 
1921. ee 
Includes a few new combinations, such as Acyntha Kirkii (Baker) Rusby, page 23- 
