INDEX 
Pteris longifolia, 384*, 388* 
Pterocymbium tinctorium, 283* 
Ptilidium, 376* ~ 
Puccinia graminis (wheat rust), 355*, 
356*, 357*, 359, 362 
Puccinia thwaitesii, 357* 
Puftballs, 360*, 361*, 363 
Pulp, wood, 151-152 
Pulque, 184 
Pulvini, 91-92 
Pumpkin, flowers of, 208* 
Purity of gametes, 235 
Pycnia, 356*, 357 
Pycnospores, 357 
Pyrenoids, 319 
Quassia amara, leaves of, 77* 
Quercus bennettii (oak), wood fibers of, 
120% 
Rachis, 73 
Radicle, 279, 295-296 
Radish, 109*, 177*, 182*, 208, 249 
Rafflesia manillana, 12*, 164* 
Rain tree (Enterolobium saman), 107* ; 
flower cluster of, 217*; leavesof, 46%, 
72*, 93* 
Rainfall, 446-447 
Ramie, 146 
Raphides, 32, 33 
Raphidophora, stem of, 176* 
Rattans (Calamus), 80, 81*, 169, 484*, 
435* 
Rays, secondary pith, 148-149 
Receptacle (torus), 209 
Recessive characters, 237 
Red alge (Rhodophyceae), 340, 342 
343* 
Redwoods, 422* ; forest of, 441* 
Regular flowers, 205 
Reindeer moss, 366 
Reproduction, 6-7, 78, 8320-321 ; asex- 
ual, 204-205 ; in bacteria, 308; in 
blue-green alge, 313-314 ; in Chara, 
329 ; in flagellates, 316 ; flower in, 
204-205 ; in fungi, 343; in Oedogo- 
nium, 324-327 ; protoplasm in, 21; in 
Rhizopus, 347-849 ; by root, 203 ; in 
Saprolegnia, 345 ; sexual, 5-6, 204- 
205 ; in Spirogyra, 385-337 ; by stem, 
165, 171-172 ; in Ulothrix, 322-324 ; 
in Vaucheria, 330-334 
Reserve food, 288-293 
Resin canals, 420 
Resin ducts, 127-128 
Resins, 77, 150 
479 
Respiration, anaérobic, 53; in animals, 
47; definition of, 49; demonstra- 
tion of, 51-52 ; in germination, 300 ; 
importance of, 49-50 ; intramolecu- 
lar, 53; oxygen supply for, 44, 50, 
53-54 ; in plants, 49-54; process of, 
50-51 ; temperature for, 54 
Rest period of seed, 295-298. See 
Dormancy 
Resting nucleus, 223-224 
Reticulum, 224 
Rhizoids on ferns, 388-389, 391*, 393% ; 
on mosses, 367 
Rhizomes, 171-172, 453 ; in Equisetum, 
398 ; and etiolation, 114 
Rhizophora, 199-201, 203, 296*, 460*, 
461-462 
Rhizophora candelaria , 200* 
Rhizophoraceae, 295, 462 
Rhizopus nigricans, 347-349 
Rhodophyceae (red alge), 340, 342, 
343* 
Riccia, 367*, 368*, 369* 370*, 371%, 
372-874 ; fertilization of, 393* 
Ricciales, 372-374; and Jungerman- 
niales, 8379; and Marchantiales, 375, 
377 
Rice (Oryza sativa), 14, 115, 254; 
parasite on, 353* ; starch grains of, 
45* 
Ricinus communis (castor-oil plant), 
flowers of, 209* ; leaf of, 72* ; seeds 
of, 280*; stem of, 117* 
Rigidity, 138-139; of collenchyma, 
119-120 ; of stem, 118-119 
Rivularia, 310* 
Rocks, 264-265 
Root, absorption of materials in, 175, 
180-186 ; absorptive organs of, 4; 
anatomy of, 140, 191-198 ; functions 
Of, 5,° 78,.80,, 822 175-1774191-192: 
geotropism in, 107-109; growth of, 
177-180 ; location of, 5 ; oxygen for, 
50; and soil, 186-191; specialized, 
198-203 
Root cuttings, 107 
Root hairs, 180-182 
Root tip, 16* 
Rootcap, 177-178, 180 
Rosette crystal, 31*, 32 
Rosette plants, 83-87 
Rubber, 128 
Ruby glass, 19 
Runners, 171-172 
Rust, 9, 355*, 358*. See Protobasidii 
Rye, 213 
