INDilX 



469 



Hazel, pollen of, carried by wind, 300. 



starch in, daring winter, 259. 

 Hazel, Witch, dispersal of seeds. 321. 

 Heart wood, 244, 245. 

 Heat, as> preservative, 386. 



effect of. on absorption by root, 332. 



bacteria, 363, 364. 



direction of growth of stem and 



root, 88, 89. 



— evaporation, 115. 



flora, 351, 356. 



— flower and fmit production, 347. 



growth, 252. 



leaf, 345. 



— Mould. 394. 



opening and closing of flowers, 



296. 



eflfect of on plants, 352, 353, 3o4.* 355-358. 



transformation of fat into 



starch, 259. 



transpiration, 207. 



entrance of, into seed, 42, * 43. 



excessive, injurions, 352. 



of respiration, 35, 36*, 287. 



lack of, kills plants, 352-354. 



prevents chlorophyll formation, 



354.* 



— — preserves foods, etc., 386. 



— — produces rosette form, 357. 

 needed by plant, 326. 



— to awaken seed, 4, 5,* 6. 

 set free by flowers, 287. 

 seeds, 35, i:6.* 



Heath plants love sour humus, 351. 



protection of, against drying, 213, 333. 

 Helianthus. See Sunflower. 

 Heliotropism. 264, 346. 

 Hemizonia. See Tarweed. 

 Hen -and -chickens, protection of, against 

 drying, 215. 



storage of water by, 334. 



transpiration of, 216. 



water reservoirs of, 215. 

 Herb Robert, protection of pollen of, 295. 

 Hereditary percentage, 436, 442. 

 Heredity, 411,* 413,* 416,* 422, 423,* 424,* 

 425*. 426,* 427,* 428, 429,* 434, 436, 442. 

 Hickorj\ flower-buds of, 286. 



path of water in, 226. 



Hickory, preparation for flowering of. 286. 



seed-cover of, holds water, 29. 



wood of, 230. 

 Hieraeium. See Hawkweed. 

 Hilgard, acknowledgment to, i. 



— on soils, 126,* 160. 

 Hilum. 1,* 2. 



as place for entrance of water, 10. 

 Hippuris, 342. 

 Histology of flower, 290,* 291.* 



— fnngi, 395,* 396,* 397,* 399,* 402,* 403,* 



404,* 407.* 



— leaf, 196-198,* 199*-201,* 202,* 208.* 



209,* 333. 334,* 335,* 336.* 337,* 338,* 

 340,* 344,* 345,* 402,* 403,* 404.* 



— leaf-stalk. 212. 



— root, 120,* 121. 



— seed, 65,* 66, 67, 177, 178. 



— stem, 224*-227,* 228-230,* 231, 232,* 233, 



234*-236,* 267,* 268,* 328, 333,* 334,* 

 335.* 

 Holly, cuticle of, 334.* 



protection of, against animals, 222. 



drying, 333, 334.* 



transpiration of, 204. 

 HoUyhock, rust of, 406. 

 Holmes, on fertilizers, 153. 

 Honey. See Nectar. 



Honey Locust, protection of, against ani- 

 mals, 222. 

 Honeysuckle family, cross -pollination of, 

 303. 



flower, position of, 307. 

 Hop, eross-pollination of, 302. 



dispersal of seeds of, 322-323,* 



twining of, 275. 

 Hopkins, work of, 434-439. 

 Horehound, hairy covering of leaf, 213. 

 Hornblende, 107. 

 Homwort, 339. 

 Horse-beau, germination of, 81, 82,* 86. 



micropyle of, 10. 



seed of, structure of, 1,* 2. 



seed-leaf of, contrasted with foliage leaf. 

 180-186. 



function of. 178, 179. 



microscopic structure of, 65,* 66. 



Horse-chestnut, flower-buds of. 286. 



hairy covering of leaf of, 213. 



