INDEX 
Pome type of fruit, 78, 78*. 
Pond Lily society, 511*. 
Pondweed societies, 505. 
Porella, 415. 
Postelsia, 319. 
Potassium, as a soil constituent, 157. 
Potato Blight, 357, 358*, 359*, 360* 
Potato scab, 348, 247*. 
Powdery Mildews, 373-375; on Apple 
leaf, 372; on Hop, 373*. 
Powdery Scab of Irish Potato, 340, 
341*. 
Prairies, 508. 
Pressure within cells, 118. 
Primary endosperm nucleus, 40. 
Primary growth, 214. 
Primary leaves, 234. 
Primary meristems, 127. 
Primary rays, 203, 201* 
Primary root, 102. 
Primary veins, 245. 
Procarp, 326, 326*. 
Processes in cell activity, 116. 
Promycelium, 394. 
Prop roots, 139. 
Propagation, by roots, 163-165; by 
stems, 225-233. 
Prostrate stems, 172, 173. 
Proteases, 284. 
Protective tissues, 127. 
Protection against transpiration, 266. 
Proteins, 256, 280; kinds, 281. 
Prothallial cell, 456. 
Prothallus, 432, 432*. 
Protoascales (Yeasts), 377, 377*. 
Protococcales, 302; described, 307. 
Protococcus, 307. 
Protodiscales, 364; described, 377, 
376.* 
Protonema, 421. 
Protoplasm, 39, 274; described, 113, 
114*. 
Protoplast, 113. 
Protozoa, 155. 
Pruning, 221-225. 
Pseudopodium, 423. 
Pteridophytes, 292; described, 425- 
414. 
581 
Pteridosperms, 445. 
Ptomaines, 283. 
Puccinia Asparagi, 403. 
Puccinia graminis, 396-401. 
Puffballs, 382; described, 389-392. 
Pulsating vacuoles, 303, 303*; in 
Euglena, 330, 330*. 
Pumpkin, flowers, 12, 12*; length of 
root system, 135. 
Purity and analysis. of seeds, 74. 
Pyrenoid, 303, 303*. 
Pyrenomycetales, 
369-373. 
Pyronema, 367, 367*. 
364; described, 
Quack Grass, 86. 
Quarter-sawed Oak, 203, 202*. 
Quetclet’s law, 525, 526*. 
Quince, 142. 
Raceme, 28, 28*, 32*. 
Rachilla, 20, 21*. 
 Rachis, 20, 20*, 21*. 
’ Radicle, of Bean, 56, 56*; of Corn, 63, 
102, 63*, 101*; development, 
466, 467, 466*, 467*. 
Ranunculaceae, 481; flower, 481*. 
Raphe, 57, 57*. 
Rays, primary and secondary, 203. 
Receptacle, 12, 10*, 11* 
Recessive character, 543. 
Red Algae, 296; described, 324 329. 
Red Clover, flower, 23, 12*, 23*; fer- 
tilization in, 42*; hard seeds, 69; 
impurities in seeds of, 75*; life 
cycle, 469*; ovule, 38*; pistil, 36, 
35*; pollination, 47*; seedling, 
109, 109*. 
Red Heart Rot, 389. 
Reduction division, 412, 413*; as re- 
lated to segregation, 554, 555*. 
Regions of growth, in roots, 145, 149, 
145*, 149*; in stems, 213, 214*, 
215*. 
Reproductive tissues, 133. 
Reserve cellulose, 278, 279*. 
Reserve foods, 277. 
