INDEX 
Grapefruit (Citrus decumana), flower 
of, 206* ; fruit of, 274* ; leaf of, 77* 
Graphite, 9 
Grasses, 38, 115, 130, 186, 188, 146, 
204, 215, 216, 302, 453; leaf bases 
of, 79, ¥3 ; photosynthesis in, 38 
Grassland, 452-453 
Gravel, 186 
Gravity, 107-109 
Greeks, 271 “4 
Green alge. See Chlorophyceae 
Growing point in roots, 177 
_ Growth, abnormal forms of, 164; 
apical, 96-98 ; conditions for, 299 ; 
definition of, 159; effect of external 
factors on, 160-164 ; in germination, 
301-303 ; grand period of, 159; in- 
tercalary, 97-98 ; in protoplasm, 21; 
of roots, 177-180 ; of stem, 159-164 
Guania microcarpa, modified stem of, 
167* 
Guard cells of stoma, 29, 67-70 
Guava (Psidium guajava), berry of, 
274* ; branches of, 96*, 100* 
Gum chicle, 128 
Gums, 150 
Gutta-percha, 128 
Gymnospermae, 404, 407-428 ; arche- 
gonia of, 405; Cycadales, 407-417 ; 
microsporangia and microspores of, 
405 ; relationship of, 419* 
Habit, 11 
Habitat, 11 
Haematomma puniceum, 362* 
Hairs, absorbing, 82, 88; branched, 
74* ; bristlelike, 75*, 76; glandular, 
76*, 77; root, 180-181; stellate, 74* ; 
stinging, 75*, 76; trichomes, 74-77 
Hakea, branch of, 61* 
Halimeda opuntia, 334* 
Haustorium of Cuscuta, 170*, 171*; of . 
Viscum orientale, 13* 
Heartwood, 150; dead cells of, 16 
Heat, effect of, on growth of twigs, 
161*; and growth, 160-163; liber- 
ated in oxidation, 48-49; and pul- 
vini, 91-92; of respiration, 52; a 
stimulus to protoplasm, 22; of sun- 
light reduced by trichomes, 75 ; and 
transpiration, 59-60 
Hedychium coronarium, section of root 
of, 190* 
Helianthus angustifolius, 162* 
Helianthus cucumerifolius (sunflower), 
220* 
473 
Heliotropism, 112-113 
Hemibasidii, 355 
Hemicellulose, 290-291, 293* 
Hemileia vastatrix (coffee rust), 356* 
Hemiparasites, 13 
Hemp, 146; Manila, 132 
Hepaticae, 367; alternation of gen- 
erations in, 371-372; and Antho- 
cerotales, 379-380; gametophyte 
of, 368-370 ; and Jungermanniales, 
377, 379; and Marchantiales, 374- 
377; orders of, 372; and Riccia- 
les, 372-374; sporophyte of, 370- 
371 
Hereditary modifications of structure, 
64 
Heredity, 65; definition of, 232; defi- 
nition of terms, 236; Mendelism, 
232-247 ; natural selection, 256-259 ; 
plant breeding, 248-256 
Heritiera littoralis, fruit of, 285* 
Heterocysts, 313 ; of Nostoc, 314* 
Heterogametes, 321 
Heterotypic mitosis, 229-231 
Heterozygous, meaning of, 236 
Hevea brasiliensis (Para rubber), 128 
Hibiscus, flower of, 210*; ovary of, 
207* ; sections of leaves of, 28*, 30*, 
35* 
Hilum, 281 
Homozygous, meaning of, 236 
Hooks, 78, 80, 165*, 169, 287 
Horizontal branches, 111-112 
Horse-chestnut, stem of, 99* 
Horsetails, 398, 399. See Equisetineae 
Host, 12*, 13 
Humidity, 57-60 
Humus, 189 
Hybrid, 284-2385, 249 
Hybrid vigor, 253-254 
Hybridization, variations due to, 249- 
250 
Hydnophytum, 173* 
Hydration, of colloids, 39, 142; in 
leaves, 89-42 ; of protoplasm, 20 
Hydrogen, 9; in carbohydrates, 44 ; 
in oxidation, 48 ; in photosynthesis, 
47; in proteins, 18; in respiration, 
49, 50; source of, 10 
Hydrophytes, 13 
Hymenium, 350*, 351, 852*, 354*, 860*, 
365* 
Hymenomycetes, 363 
Hyphe, 348, 348* 
Hypocotyl, 303 
Hyptis suaveolens, seed of, 287* 
