INDEX 
(The numbers with stars refer to the pages on which the illustrations are given.) 
Absciss layer, 184. 
Absorption of water, by seeds, 91; by 
roots, 158; factors that hinder, 
159; selective, 159. 
Absorptive zone, 143, 144*. 
Abundance and Distribution of 
plants, 5. 
Abutilon Theophrasti, 487. 
Accessory buds, 206. 
Aceraceae, 487. 
Achene, 60, 79, 60*. 
Achillea millefolium, 24*. 
Acids, 120; malic, 285; oxalic, 285; 
citric, 285; tartaric, 285. 
Aconite, 482. 
Acorn, 80, 83*. 
Actinomyces chromogenus, 348, 344*, 
347*. 
Active buds, 211. 
Adventitious buds, 206, 207*. 
Adventitious roots, 140. 
Aécidiospores, 398, 399*. 
Aérial stems, 172. 
Aérobic Bacteria, 343. 
Aérotropism, 152. 
After-ripening, 69. : 
Agarics, 385, 385*, 386*. 
Agaricus campestris, 385, 386*. 
Agave, 498, 498*. 
Aggregate fruits, 79*, 80. 
Agropyron repens, 74. 
Air chamber, 249. 
Air, in the soil, 153. 
Air roots, 162. 
Albugo, 359. 
Albumins, 281. 
Albuminous seeds, 60. 
Aleuron layer, 64, 65, 66*, 280*. 
Alfalfa Dodder, 489. 
Alfalfa, seeds, 74, 87, 74*; fruits, 82; 
stem, 193*, 194*; plant, 209%; 
leaf, 238*. 
Algae, 296. 
Blue-green, 297-301. 
Green, 301-318. 
Brown, 318-324. 
Red, 324-329. 
Alkaloids, 281, 283. 
Allelomorphs, 543, 543*; dominant, 
543; recessive, 543. 
Alternate arrangement of leaves, 238, 
239*, 240*. 
Alternation of generations, 412. 
Amanita bulbosa, 384*. 
Amaranthus albus, 84*. 
Amino acids, 120. 
Amino compounds, 281. 
Amygdalase, 285. 
Amyegdalin, 282. 
Anabolic metabolism, 273. 
Anaérobic Bacteria, 3438. 
Anaérobic respiration, 122. 
Analysis of seeds, 74. 
Anatomy, described, 2; of leaves, 
242-252; of root tip, 143; of the 
older portion of the root, 147; 
of stems, 182-203. 
Anatropous ovule, 463. 
Andreales, 417. 
Angiosperms, 293, 445; described, 
459; life cycle, 469*; classifica- 
tion, 471. 
Annuals, 171. 
Annual rings, 197, 201, 198*, 202*. 
Annular vessels, 188, 189*, 190*, 
195*. 
Annulus, 386, 429, 385*, 386*, 430*. 
Anther, 41, 41*. 
567 
