INDEX 



Honckenya, see Arenaria (Honckenya) 



peploides agg. 

 Honeysuckle, see Lonicera periclymemim 

 Hooded Ladies'-tresses, see Spiranthes 



romanzoffiona 

 Hookworm, infections, treatment of, 



263 

 Hop, see Hiimulus lupulus 

 Hoppner Sedge, see Carex subspathacea 

 Hordeum vulgare s.l. (Barley), 226, 257, 



260, 282, 370, 454 



, world production of, 229 



Horizons, soil, 297, 299 

 Horizontal vicariad, 202 

 Hormonal herbicide, 276 

 Horn-wort, see Ceratophylhim 

 Hornbeam, see Carpinus 

 Horse-chestnut, see Aesculus 



radish, 262 



Horsetail, see Equisetum 

 Horsetails, see Equisetineae 

 Horticulture, 3, 233, 277-8, 564, 577-8 

 Host, 80, 251-2, 432, 433, 435, 436, 437, 

 Hot desert, 449 [524 



— springs, flora of, 476, 499 

 Hoyle, A. C, 441 

 Huckleberry, 258 



Hudson Bay, 292, 384, 406, 537 



— Strait, 385, 386, 393, 400, 401 

 Hudsonian belt, 346, 349 



Hulten, E., xvii, 185, 189-91, 195, 199, 



203, 214 

 Human diseases, 26, 27, 577 



— environment conditioned by plants, 



255, 277 



— population of world, 224, 256 

 Humboldt, A., 21 

 Hummocks, 385, 387, 388, 399, 501 

 Humic matter, soluble, 497, 502 

 Humidus lupulus (Hop), 239, 261, 263, 



282 

 Humus, 301, 302, 303, 325, 475, 476, 



548 

 — , formation in water, 318, 325, 503 

 — , marine, 539 

 — , raw, 303 



■ — , in soil, 297, 301, 302-3 

 — , tropical, 437, 458, 462, 467, 468 

 Hura, 124 



H. crepitans (Sand-box Tree), 121 

 Hutchinson, G. E., xviii, 16, 506 

 — , J., xviii, 186, 190, 193-4, 281 

 Hybrid origin of endemics, 163 

 — , polyploid, 179, 204, 234, 235, 239 

 Hybridization, 176, 177, 179, 204, 258, 



564 

 Hydra, 2 



Hydrarch subsere, 324 

 Hydraulic pressure, algal gas-Blled 



bladders and, 522 

 Hydric mean, 328 



607 



Hydrocharis morsus-ranae (Frogbit), 504 

 Hydrogen-ion concentration, see pH 



— sulphide, 497-8 



Hydrophytes, 86, 87, 93, 289, 372, 



593-5 

 Hydroponics, 278 

 Hydrosere, 319, 324, 325, 326, 333, 342, 



353. 372, 373. 462, 502-6 

 — , arctic, 405, 406 

 — , dominants of, 372 

 — , floating-leaf stage of, 325, 326, 353, 



372, 463, 504, 505 

 — , marginal to lakes, 502 

 — , reed-swamp stage of, 319, 325, 326, 



372, 40s. 406, 463, 505 

 — , sedge-meadow stage of, 325, 326, 



372 

 — , stages of, 319, 325, 326, 353, 503-4 



— of temperate regions, 325, 326, 372 

 — , tropical, 462, 463 



Hyeniales, 145 

 Hygrograph, 291 

 Hygrohypnum polar e, 109 

 Hygrophilous forest, 350, 440 

 Hygrophily, 294, 440 

 Hygrophyte, 289, 326, 505, 578 

 Hygrophytic scrub (shrubs), 325, 326, 



342, 372 

 — , woodland (forest), 325, 326, 373 

 Hygroscopic movements, 56, 125 

 Hylander, C. J., 281 

 Hymenaea courbaril (Locust), 247 

 Hymenophyllum peltatum, 420 

 Hypha (/)/. hyphae), 43, 45, 131 

 Hypnophyceae, 528 

 Hypnotic, 264 

 Hypolimnion, 477 



Iberian Peninsula, 197 

 Ice action on marginal vegetation, 475, 

 531, 536, 537, 538 



— Age, 109, 156, 157 



— bloom, algal, 490 



cap (antarctic, etc.), 162, 213, 414- 



417 



, climate near, 162 



— , dispersal and, 100, 106, 107, 109, 



491 



free tracts, plants persisting on, 162, 



163, 164, 165 



— island, 109, 491 



— , marine, seaweeds and, 531, 536, 

 537-8 



— photosynthesis under, 506 



pups (and ice-floes), 127, 388, 491, 



536, 538 

 — , recession of, 129, 159 

 Icebergs, dispersal by, 109, 490, 538 

 Iced flrn, 11, 490 

 Iceland, 184, 222, 344 

 moss, see Cetraria 



