INDEX 
Sphagnum, 382 
Spindle, 226 
Spines, 174; branches modified as, 
166* ; on desert plants, 64; mar- 
ginal, 92* ; stipular, 92* 
Spiny leaves, 90-91 
Spiral vessels, 122 
Spireme, 224 
Spirillum, 805 
Spirogyra, cell structure of, 334-835 ; 
reproduction in, 335-337 
Spirulina, 313* 
Spongy chlorenchyma, 31, 32 
Sporangium, 405; of Coniferales, 421; 
of fern, 384*, 388, 394*; of Mar- 
chantiales, 375; of Selaginella, 401— 
402 
Spore, 308, 314 
Sporophylls, 895*,396*,397*, 406%, 409%, 
410*, 411*, 419*, 420*, 421*, 423- 
424; of angiosperms, 429-430; of 
Lycopodium, 399 ; of Selaginella, 400 
Sporophyte, 876*; of angiosperms, 
429; of Anthocerotales, 377*, 378%, 
379; of bryophytes, 867-368; of 
Equisetum, 398, 399; of Filicineae, 
385-388, 391*, 395*, 397, 398; of 
Hepaticae, 370-371 ; of Lycopodium, 
399; of Marchantia, 374*, 375; of 
Musci, 380-381, 382*; of pterido- 
phytes, 383 ; of Selaginella, 400-401 ; 
of Spermatophyta, 403 
Sports, 250 
Squash (Cucurbita maxima), 169, 280 ; 
bundle of stem of, 128*; cells of 
hair of, 15*, 22*, 41*, 76* ; seed of, 
301* ; sieve plate of stem of, 121* ; 
tendril of, 167* 
Staghorn fern, 90 
Stalk, flower, 209 
Stalk cell, in Cycadales, 410; in pine, 
425 
Stalk in Marchantiales, 375, 377 
Stamens, 5*, 6, 205, 206, 207*, 405 ; 
of angiosperms, 480. See Micro- 
sporophylls 
Starch, 288*, 289*, 290*, 293, 295 ; in 
amyloplastids, 24; formation of, in 
plant, 44; grains of, 44, 45*; test 
for, 46, 126 
Starch sheath 
stems, 116-117 
Stearin, 291 
Stele, 192-198; of dicotyledons, 115, 
120-127; of ferns, 385-388; of 
monocotyledons, 130 
in dicotyledonous 
481 
Stem, bundles in, 133; coniferous, 
158-134, 407, 420-421 ; of dicotyle- 
dons, 115-129; and external con- 
ditions, 107-114, 160-164; functions 
of, 5, 78, 95-96; growth in, 159-. 
164 ; mechanical tissues in, 185-140; 
of monocotyledons, 129-133; move- 
ment of materials in, 140-142 ; sec- 
ondary thickening in, 142-159; 
specialized, 165-174; structure of, 
96-107 ; types of, 115 
Sterigmata, 355 ; 
Stigma, 5, 6, 205-206 ; of angiosperms, 
430-432 ; of Spermatophyta, 405 
Stinging hairs, 76. See Trichomes 
Stipules, 79, 90, 91; of garden pea, 
77-78 ; of leaves, 26-27; on Morus 
alba (mulberry), 26* 
Stock, 157 
Stomata, 29, 62*, 67-70, 75, 101; in 
dicotyledonous stem, 116; distribu- 
tion of, 29 ; and lenticels, 155 ; num- 
ber and arrangement of, 63 ; opening 
and closing of, 67-70; respiration 
through, 44; in transpiration, 55 
Stone cells, 120 
Storage, in leaf, 78, 89; in root, 177*, 
195, 208* ; in stem, 96, 162, 165, 172- 
174; of water, 166*, 173* 
Storage roots, 176*, 177* 
Strawberry, fruit of, 273* 
Striations in starch grains, 44, 45* 
Strobilus, 395*, 396*, 399*, 429; of 
Ginkgo, 419* ; of Selaginella, 400 
Structural modifications, 60-65 
Structure of leaves, 26, 27 
Struggle for existence, 256-257 
Style, 205-206 ; of angiosperms, 432 
Subclasses, 211 
Suberin, 158; in cell walls, 17 
Submerged plants, 458; aération of, 
53-54 ; leaves of, 82-83 
Subtropical and warm temperate rain 
forests, 489-440 
Succession and 
462-464 
Suckers, 204 
Sucrose, 289 
Sugar apple (Anona squamosa), 273* 
Sugar cane (Saccharum officinarum), 
115, 182*, 354* ; bundles of, 132, 133; 
smut on, 356; tip of stalk of, 80* 
Sugars, 142, 289, 298, 295; carbohy- 
drates, 44; of photosynthesis, 4, 26, 
42-43 ; in protoplasm, 20; in respi- 
ration, 50 
climax vegetation, 
