Aquatic plants, 1 1 



Arctagrostis latifolia, 57 



Arctic region, 17, 36, 72, 78, 80, 82, 



94, 139, 157, 173, 174, 187 

 Arctic-alpine region, 187 

 Arctostaphylos (Bearberries), 144, 157 



uva-ursi, 139, 143; alpina, 139 

 Area, basal, 102, 103, 110 

 herbage, 103 

 listing, 103 

 Arenaria obtiisiloba (Sandwort), 36 

 Aristida (Three-awns), 96 



adscensionis (six- weeks T), 11; lon- 

 giseta (red T), 23, 98, 102 

 Arizona, 11, 29, 79, 80, 88, 89, 106, 



161 

 Arkansas, 30 



Artemisia (Sagebrushes, Wormwoods) 

 absinthum (absinthe), 37; dracunculus 

 ssp. glauca, 73, 123; JiHfolia (sand 

 S.), 103; frigida (pasture Sage), 

 71, 98, 1 14; tndentata (big S.), 12, 

 31, 85, 107 

 Asia, central, 68 

 Asimina triloba (Papaw), 83 

 Aspect, 87, 135 

 Aspection, 85, 136 

 Aspen. See Populus tremuloides 

 Aspen woodland, 40, 53, 72 

 Assay, biological, 110 

 Associated species, 61, 63, 98, 126 

 Association, 126, 161, 174 

 climax, 73 

 definition, 66 

 principal, 181 

 regional, 181 



use in classification, 178, 179 

 Association index, 99 

 Association, interspecific, 34-37, 54, 



59, 77,98-99, 131 

 Association table, 121, 122 

 ^.f^er (Asters), 88, 128 



cordifolius (fall A.), 83; divaricatus 

 (fall A.), 83 

 Astragalus (Milkvetches) 



crassicarpus (ground plum), 128; mis- 

 souriensis, 98 

 Atlantic Coast, United States, 19 

 North, 56 



Atriplex (Saltbushes) 



argentea, 144; confertifolia (shadscale), 

 85; nuttallii (Nuttall S.), 144 

 Australia, 31, 36, 43, 68 

 Autecology, 1 

 Autogenic succession, 149 

 Availability, faunistic, 160 



floristic, 160 



Backflash, 62 



Balkans, 64 



Barriers, 39, 67 



Bassia uniflora (Bassia), 36 



Bearberry. See Arctostaphylos 



Beech. See Fagus 



Bek, life, 186 



Bermudagrass. See Cynodon 



Betula (Birches) 



glandulosa (glandular scrub B.), 63, 

 64; nana (dwarf alpine B.), 157, 

 161; papyrifera var. cordifolia (canoe 

 B.), 84; populifolia (gray B.), 41 



Betula glandulosa community, 1 54 



Biocenose. See Ecosystem 



Biociation, 187 



Biological control, of weeds, 53 



Biome, 68 



Biome-type, 68 



Biotype, 14,41,42,45,48, 171 



Birch. See Betula 



Birch woodland, 181 



Birds, as an ecological factor, 12, 41 



Blazing star. See Liatris 



Bluegrass, Kentucky. See Poa 



Bog, 17, 62, 69, 174 



Bothnochloa ambigua, 31 



Boundary, community, 141 



Bouteloua gracilis-Artemisia dracunculus 

 ssp. glauca association, 122-123, 

 125 



Bouteloua (Gramagrasses) 



aristidoides (needle G.), 88, 98; bar- 

 bata (six- weeks G.), 11, 88; curti- 

 pendula (side oats G.), 12, 13, 22, 

 29, 30, 73, 91, nO-.filiformis, 106; 

 gracilis (blue G.), 22, 29, 47, 48, 

 62, 72, 73, 84, 85, 88, 92, 98, 99, 

 102, 103, 107, 128, 130, 144, 160, 

 161, 165, 172; parryi (parryi G.), 



204 * Iitdex 



