INDEX 
212; Torreya, 218; Pinus, 225, 226; 
Ephedra, 236, 237; angiosperms, 271, 
272, 27 3- f 
Progeotropism, 460. 
Promycelium, 83. 
Prosenchyma, 112. 
Protective tissues, 318. 
Protein enzymes, 401. 
Proteins, 361, 391 ; synthesis of, 377. 
Prothallial tubes, Tumboa, 235. 
Prothallium, 165, 166. 
Protoascales, 70. 
Protobasidiomycetes, 81. 
Protococcales, 20 ; conclusions, 24. 
Protodiscales, 71. 
Protonema, 115, 116. 
Protoplast, 7, 297 ; work of, 298. 
Protosiphon, 34. 
Protostele, 125, 157, 159. 
Protoxylem, 157, 241. 
Pseudopodium, slime molds, 2 ; mosses, 
113,1/4, 115. 
Psilotales, 142. 
Psilotum, 142, 143. 
Pteridophytes, 122. 
Pteris, stem section, 161. 
Puccinia, 82, 83, 84, 85. 
Puffballs, 90. 
Pulque, 334. 
Pulvinus, 452. 
Purslane, photeolic movements, 455. 
Putrefaction, 355, 411. 
Pycnidia, 83. 
Pycnidiospores, 83. 
Pyrenoid, 16, 39, 40. 
Pyrenomycetales, 75. 
Pyronema, 72, 73. 
Quillworts, 138. 
Radial bundles, 248, 249. 
Ramentum, 185. 
Ranales, 279. 
Ranunculus, nectar gland, 339; root section, 
249. 
Ray flowers, 282. 
Reaction, mechanism, 431; modes, 428; 
time, 433. 
Receptacle, flower, 253 ; Marchantia, 09. 
Red algae, 54. 
Regular flowers, 256. 
Reproduction, 481. 
Resins, 413. 
Respiration, 423 ; aerobic and anaerobic, 
404 ; products, 406 ; role of oxygen, 
406. 
Reversible action, 399. 
Revolution, twiners, 468. 
Rheotropism, 473. 
Rhipsalis, chloroplasts, 376. 
Rhizopus, 67. 
Rhodophyceae, 54. 
Riccia, 93, 94, 95, 96, 97. 
Ricciaceae, 93 ; conclusions, 96. 
Ricciocarpus, 93. 
Ricinus, endosperm cell, 392; stem section, 
242, 346. 
Ringless ferns, 155. 
Rivularia, 8, 9. 
Rockweed, 49. 
Root, angiosperm, 247, 248, 249; branches, 
248; cap, 246, 247, 465; diffusion from, 
353; effect on soil, 315; hairs, 247, 248, 
312; permeable regions, 311 ; "pressure," 
336; pteridophytes, 122, 130, 131, 137, 
141, 163, 168; system, 311 ; tip, 247. 
Roripa, rootcap, 465. 
Resales, 280. 
Rotation, dinostat, 462; twiner, 468. 
Rubiales, 282. 
Rusts, 82, 83, 84, 85. 
Saccharomycetes, 70. 
Saccharose, 359. 
Sac fungi, 70. 
Sagittaria, embryo, 273, 274, 275. 
Salix, megasporangium, 262. 
Salts, and transpiration, 325 ; and water- 
proofing, 317. 
Salvinia, 771. 
Salviniaceae, 171. 
Sap pressure and turgor, 311. 
Saprolegnia, 64. 
Saprolegniales, 63. 
Saprophytes, 2, 61, 384. 
Sargassum, 52, 53 
Sarracenia, 386. 
Scalariform vessels, 241, 244. 
Scale mosses, 101. 
Scenedesmus, 21. 
Sceptridium, 149. 
Schizaeaceae, 155. 
Schizomycftes, 10. 
Schizophyceae, 4. 
Schizophytes, 4. 
Scitaminales, 278. 
Sclerodermales, 90. 
Sclerotium, 2, 77. 
Scouring rushes, 143. 
Scytonema, 9. 
Secondary xylem, 241, 344, 345. 
Secretion, 332, 337 ; emission, 338. 
Sedum, stoma, 320. 
Seeds, 180, 182, 183, 188, i8g, 212, 232; 
loss of, 355. 
Seed plants, 180. 
