480) 
Sac, of angiosperms, 430; embryo, 222; 
pollen, 206, 404 
Saccharomyces, 352-353 
Saccharum officinarum (sugar cane), 
115, 181*, 132% 
Sago, 174; starch grains of, 45* 
Samara, 277*, 278 
Sand, 186, 188 
Sap from coconut, 141*, 142 
Sapodilla (Achras sapota), berry of, 
279* 
Saprolegnia, 344-847, 349-351; rela- 
tionship of, 846-847; reproduction 
in, 8345; and Rhizopus, 347 
Saprophyte, 14*, 309, 348, 344; leaves 
of, 94. See Fungi and Bacteria 
Sapwood, 150 
Sargassum 339*, 340 
Sarracenia, leaf of, 83* 
Savanna, 452-458, 455* 
Scalding, 57 
Scalelike leaves, 60* 
Scales, bud, 92, 94, 99-101; of Elae- 
agnus philippensis, 75*; forms of 
trichomes, 74; of pine, 422 
Scars, 26*, 98, 99*, 100 
Schizocarpic fruits, 277, 278 
Scion, 157 
Sclerenchyma, of stems of dicotyle- 
dons, 120; in Ixora, 38*; in leaf, 
37-38 
Scramblers, 169 
Secondary changes in bark, 152-153 
Secondary meristem, 154 
Secondary pith rays, 148-149 
Secondary thickening, in Cycadales, 
407-408 ; in stem, 142-159 ; in stem 
of Muntingia calabura, 144* ; instem 
of ylang-ylang, 148*; in wood of 
linden, 145* 
Securidaca corymbosa, samara of, 277* 
Sedges, 115, 170 
Sedimentary rocks, 264-265 
Seed, 6, 206, 276*, 279-308 ; of angio- 
sperm, 432; characters of, 239-240 ; 
coats of, 281, 297-298 ; of Conifera- 
les, 421; of Cycadales, 408*, 410-411 ; 
digestion of food in, 293-295; dis- 
persal of, 282-288 ; function of, 78, 
88-89; germination of, 295-303; of 
Ginkgo, 418*; minute, 282; of pine, 
415%, 425, 427; reserve food in, 288- 
293 ; of Spermatophyta, 406-407 ; of 
Zamia, 416% 
Selaginella, 399*, 400-402; fertiliza- 
tion of, 8393* ; sporangia of, 401-402 
A TEXTBOOK OF GENERAL BOTANY 
Selaginellales, 400-402 
Selection, 248; natural, 256-259 
Self-fertilization. See Inbreeding 
Self-pollination, 214 
Self-pruning, 114 
Sensitive plant (Mimosa pudica), leaves: 
of, 92, 938*; pod of, 277*; root of, 
308* 
Sepals, 209 
Sequoia, 420 
Sessile leaves, 71 
Sexual reproduction, 204-205 
Sexuality, 258-259 ; of flowers, 206— 
207 
Shield cells, 829 
Sieve plate of squash, 121* 
Sieve tubes, 140; of dicotyledons, 123- 
124 
Silt, 186 
Simple leaf, 73 
Siphonales, 330, 384 
Siphonostele, 386-387 
Sleep movements of pulvini, 91-92 
Smilax leucophylla, 79; leaf of, 81* 
Smuts, 355-356. See Hemibasidii 
Soil, 10-11, 186-189; air in, 10; ele- 
ments in, 11; humus in, 189; mois- 
ture in, 188-189; movement of 
water in, 186-187; organisms in, 
189; physical characteristics of, 
181; relation of, to transpiration, 
188; and respiration, 53; and root 
hairs, 181; structure of, 187-188; 
texture of, 186; water films in, 10; 
weight of, 188 
Solute, 184 
Solution, 18, 19 
Solvent, 39, 40, 184 
Sonneratia caseolaris, 461* 
Soot, 9 
Spathe, 219 
Species, 211-214 
Spermatophyta, 304, 408-482; angio- 
sperms, 428-482; and A nthocerotales, 
380; Coniferales, 420-428 ; Cycadales, 
407-417; Ginkgoales, 417-419 ; gym- 
nosperms, 407-428 ; megasporangium 
and female gametophyte of, 404-405 ; 
microsporangia and microspores of, 
405 ; and Musci, 381 ; seed of, 406-407 
Spermatozoid, 825, 3869*; of bryo- 
phytes, 867; of Cycadales, 410; of 
Cycas, 415*; of ferns, 389, 390*, 
392*, 393* ; of liverworts, 370; of 
Selaginella, 401* ; of Spermatophyta, 
405 : 
