International Botanical Congress, 



Third, 66 

 Interrelations among species, 26-54 



conjunctive, 26 



disjunctive, 26, 44 



effects on plant groupings, 62 

 Invasion, 32, 39, 40, 47, 61, 64, 146, 

 155 



and mutualism, 54 



into similar habitats, 68 

 Iowa, 32, 80, 113, 127, 179 

 Ireland, 41 

 Iris, 43 

 Israel, 58 



Iva axillaris (Poverty weed), 145 

 Iverson, J., 95 



Jiiglans nigra (Black walnut), 37 

 Juniper. See Jumperus 

 Juniper-pinyon zone, 187 

 Jumperus (Junipers), 129 

 communis (J.), 41 



Kansas, 53, 140 



Kendeigh, S. C, 187 



Knapp, R., 181, 187 



hobresia myosuroides (Kobresia), 158 



Koeleria cristata (Junegrass), 70, 84 



Lambs quarters. See Chenopodium 



Land capability, 176 



Lapland, 57, 139 



Larch (Larix), 37 



Larrea divaricata (Creosote bush), 79 



Layer of vegetation, 82-83 



effect of grazing and other influ- 

 ences on, 85 

 Leafhopper, beet, 51 

 Leaf-to-stem- ratio, 92 

 Lepidium densiflorum (Pepperweed), 144 

 Lespedeza, 1 1 1 



Lesquerella gordoni (Bladder pod), 88 

 Liatris (Blazing star), 113 

 Life cycle, 15 

 Life-form, 67, 68, 77, 92-96 



and association of species, 28, 34, 

 59, 72, 93, 96 



and competition, 32 



and cover, 102 



and cyclic change, 165 



and dominance, 128 



and population density, 100 



and physiognomy, 130 



and stratification, 82, 128, 151 



and succession, 151, 156 



definition, 92 



use in classifying vegetation, 173, 

 177, 186 

 Life-span of species, 142, 146 

 Light, 10 



Lindera benzoin (Spice-bush), 83 

 Line-interception method, 103 

 Linum catharticum (Wild flax), 36 

 Liriodendron tulipifera (Tulip tree), 83 

 Locust, black (Robima pseudacacia), 53 

 Locusts, requirements of, 49 

 Loiseleuria procumbens (Alpine azalea), 



116, 117, 157 

 Lolium perenne (Perennial ryegrass), 35, 



48 

 Louisiana, 52, 65, 112 

 Lupinus (Lupine), 88 

 Luzula confusa (Northern wood-rush), 



16 

 Lycopodium (Clubmosses), 80 



tnstachyum, 84 



Magnolia (Magnolias) 



macrophylla (big leaf M.), 83; tripetala 

 (umbrella M.), 83 



Maianthemum canadense (Wild lily-of- 

 the-valley), 80 



Major, J., 136 



Management of ecological resources, 

 48 



Manzanita (Arctostaphylos), 63 



Maqui, 64 



Marsh, 62, 67, 146 



Martin, N. D., 69 



Maryland, 50, 85 



McMillan, C, 15 



Medicago sativa. See Alfalfa 



Mediterranean region, 64, 87, 88, 187 



Melilotus (Sweet clovers), 1 1 1 



officinalis (yellow S. c), Madrid var., 

 32 



Mendelian population, 42, 69 



Menyanthes trifoliata (Buckbean), 17 



Mercunalis perenms (Perennial mer- 

 cury), 41 



Inaex • 211 



