Index 



473 



Perennial plants, 241. 



Periclinal chimsera, 148. 



Periodicals, breeding, 332. 



Phenotype, 327. 



Physalis, 104. 



Pineapple hybrids, variation of, 123. 



Pistils, 271. 



Plant-breeding : associations, state, 

 300; books, 328; by selection, 

 218; denned, 212; forward 

 movement in, 294 ; instruction, 

 321; laboratory, U. S. Dept. 

 Agri., 311; projects, 315; use 

 of term, 296. 



Plant improvement a serious busi- 

 ness, 298. 



Plant introductions, division of, 

 312. 



Plants, differences compared with 

 animals, 10. 



Plant-to-row, 308. 



Plateation, 397 ; denned, 327. 



Plums, 212, 294. 



Pollen, 280. 



Pollen storage, 289. 



Pollination, 270 ; process of cross, 

 281, 289; uncertainties of, 140. 



Poncirus trifoliata, 312. 



Population, 41. 



Potatoes, 241. 



Presence-and-absence hypothesis, 

 181. 



Pride Butte wheat, origin of, 91. 



Probabilities, theorem of, 169. 



Probable error, 50. 



Punnett, 183, 184. 



Quetelet curve, 44. 



Radishes, division of, 239. 

 Raspberries, hybrid, 235. 

 Recessive characters, 327. 

 Recessiveness, 165. 

 Regel, cited, 295. 



Reproduction, difference between 

 plants and animals, 10. 



Retrograde varieties, 65. 

 Rogers' grape hybrids, 235. 

 Roguing, 251. 

 Russian apples, 212, 258, 295. 



Savoy cabbage, 244. 



Score card, use of, 236. 



Sea Island cotton, 312. 



Sectional chimsera, 148. 



Seed, change of, 28. 



Segregation, 327. 



Selection, accumulative, 209 ; ar- 

 tificial, 37, 243 ; individual, 308 ; 

 mass, 307; methodical, 307; 

 plant-breeding by, 218. 



Sex, a factor in variation, 15, 215 ; 

 influence on hybrids, 138 ; origin 

 and function of, 95. 



Shirley poppy, 76. 



Shull, 190, 318. 



Simplex, 327. 



Snapdragon, 83. 



Snyder blackberry, 255. 



Solanaceous plants, 222. 



Solanum darwinianum, 147; Gart- 

 nerianum, 147 ; graft-hybrids, 146 ; 

 kolreuterianum, 147 ; proteus, 147 ; 

 tubingense, 146. 



Somatic, 327. 



Species, definition, 8. 



Species-formation, 8. 



Spencer, 105. 



Spillman, 180, 194. 



Sport, 39. 



Sprenger, 55. 



Squares, method of, 169. 



Squashes, 128, 140. 



Stamens, 271. 



State experiment stations, 310. 



State plant-breeding associations, 

 302. 



Statistical methods (see biometry) . 



St. Hilaire, Geoffrey, 58. 



Stout, A. B., 318. 



Struggle for life, a cause of varia- 

 tion, 30. 



