INDEX 



Arctic, scrub, 390-2 

 • — , sectors of, 184, 185 



— serai types, 405-9 



■ — , short growing-season in, 78 



• — snow, coloured, 490 



— , southern boundary of, 184, 185, 380 



— species, in Tropics, 413 



— spora in, 99 



— - subarctic ecotone, 292, 343-8 

 ■ arctic sequence, 173 



— , succession in, 390, 405-9 



— , theory of origin of floras in, 171 



— , trees absent from, 380 



— tundra, 213, 382-90 



— uplands, 410 



- — vegetation, 62, 381-409, 535-7 

 • — , vegetative propagation in, 79 



— Willow, see Salix arctica s.l. 

 Arctium (Burdock), 112 

 ArctopJiilafidva agg. (Tawny Arctophila), 

 Arctostaphylos (Bearberry), 359 [405 



A. alpina agg. (Alpine Bearberry), 407 

 Area (range), 5, 8, 9, 17, 182, 188, 196, 

 208, 577 



— of world under forest, 246, 247, 556 



— patterns, 9 



— , potential, 9, 175-7 



— , types of, 5, 182-212 



Arenaria (Sandwort), 116, 412 



A. ciliata s.l. (Fringed Sandwort), 402 

 A. humifusa (Low Sandwort), 198 

 A. (Honckenyo) peploides agg. (Sea- 

 beach Sandwort, Sea-purslane), 

 107, 183, 371, 399 



Aretes, 546 



Argentina, pampas of, 363 



— , savanna-woodland of, 442 



— , Triassic flora of, 149 



Arid climate in past times, 148, 149 



— conditions in rain-shadow of moun- 



tains, 160 

 in Permian times, 148 



— regions, erosional features of, 547 



— , physiographic effects in, 294 



Aridity, evidence of, 450 



Aril, 113 



Aristolochia (Birthwort), 221 



Arizona desert and near-desert, 83, 85, 



451 



Armerm maritima s.l. (Sea-pink), 369 



Arnica alpina s.l. (Alpine Arnica), 408 



Arnold, C. A., 145, 153 



Aroids, see Araceae 



Arrowroot, 269 



Artemisia (Wormwood), 173, 365 



A. tridentata (Sage-brush), 364 

 Arthrophyta, 135 

 Artichoke, 258 

 Artificial changes in vegetation, 215, 566 



— dyes, 274 



— selection, 216, 218, 223, 226, 564 



Artificial strains, 564 



Artocarpus altilis (Breadfruit), 242, 258 



Asafoetida, 273 



Asclepias (Milkweed, Silkweed), 99, loi, 



104, 105, 194, 196, 271 

 Ascophyllum nodosum, 522 

 Asexual generation, 38, 39, 59 



— reproduction, 32, 37, 39, 45, 64, 69 

 Ash, see Fraxinus, F. excelsior, etc. 

 Asia, 187, 192,234,235,355 



— , areas under forest, 246 



— , coniferous forests of, 345 



— , deserts of, 366, 376, 449, 452, 453 



— , early cultivation in, 253-4 



— , flora of, 156 



— Minor, Rye in, 226 

 , semi-deserts of, 365 



— , savanna-type country in 444 

 — , trees introduced from, 243 

 Asparagus, 258 

 Aspect, ecological, 333, 340 

 — , physiographic, 285, 294, 295, 296, 

 322, 375, 413, 470, 544 



— (seasonal) society, 334, 340 

 Aspen, see Populus 

 Aspidium, 264 



Assam rubber, 272 



Association, 333-4, 335, 349, 392, 529 



Associes, 334, 349, 464 



Associule, 434 



Asterionella formosa, 483 



Asthma, treatment of, 264 



Astringent, 264 



Atlantic elements of flora, 211 



— Ocean, 157, 174, 249, 516, 533 

 , mangroves of, 457 



, woody plants common to both 



— Period, 173 [sides of, 243 

 Atmometer, 291, 293 

 Atmospheric conditions affecting life, 10 

 Atrichum (Catliarinea), 53 



Atriplex (Orache), 371 



A. caniim (Salt-bush), 365 

 Attachment, algal, 475, 494, 498, 503, 

 Attar of roses, 275 [514, 524, 528 



Atwood, A. C, 214, 378 

 Audus, L. J., 13, 580 

 Aureomycin, 265 

 Auricularia, 45 

 Austral zone, 186, 520, 532 

 Australasia, glaciation in, 160 

 — , Glossopteris flora in, 149 

 — , grassland in, 363 

 — , land-bridge to, supposed, 171 

 Australia, 63, 194, 196, 197, 247, 257, 



263, 264, 379, 446, 448 

 — , alien plants in, 119, 249, 574 

 — , area of forest in, 246 

 — , benthos of, 530, 535 

 — , deserts in, 365, 449, 450 

 — , European weeds in, 249 



