INDEX 
native capacity, 98-101; types, 
58-67. 
Segregation and purity of gametes, 
543. 
Segregation and reduction division, 
554. 
Selaginella, 438; described, 440-444. 
Selection, 557. 
Selection of mutants, 561. 
Selective absorption, 159. 
Self-pollination, 48. 
Semi-permeable membrane, 117. 
Sepals, 11, 10*, 11*. 
Sessile leaf, 235, 235*. 
Seta, 420. 
Sex cells, 302. 
Sex organs, 302. 
Sheep Sorrel, 479*. 
Sieve tubes, 131. 
Silphium perfoliatum, 236*. 
Simple stems, 167. 
Sinigrin, 283. 
Siphonales, 302; described, 316, 316*, 
317*. 
Smartweed, 479*. 
Smuts, 384; described, 392-396. 
Soil, as the home of roots, 152-162; 
as an ecological factor, 502; 
microérganisms, 155; origin, 152; 
rock constituents, 152; solution, 
157; water, air, and humus, 153. 
Solonaceae, 491. 
Solanin, 283. 
Solanum Carolinense, 492. 
Solanum nigrum, 491. 
Solanum rostratum, 492. 
Solitary flowers, 27. 
Solsola Kali, var. tenuitfolia, 480*. 
Somatoplasm, 532. 
Soredia, 381. 
Sorus, 429, 430*. 
Sour Cherry, 212, 212* 
Spawn of the Mushroom, 387. 
Special forms of leaves, 270-273. 
Species, in classification, 291. 
Spermatophytes, 292; described, 445- 
470. 
Sperms, 302. 
583 
Sphagnales, 417; described, 422-424. 
Sphagnum, 422, 423*. 
Spike, 17, 29, 29%, 32*. 
Spikelets, of Corn, 17, 18*, 19*; of 
Oats, 20, 20*, 21*; of Wheat, 22, 
22*. 
Spindle fibers, 124. 
Spiral vessel, 188, 189*, 190*. 
Spirillum, 341. 
Spirogyra, 315, 315*. 
Spongospora subterranea, 341. 
Spongy tissue, 249, 250*. 
Sporangia, 320, 338. 
Sporangiophore, 437. 
Spore, 338; of Bacteria, 343, 343*. 
Sporidia, 394. 
Sporophore, 383. 
Sporophylls, 437, 439, 441, 447, 448, 
452, 453, 454, 460, 462. 
Sporophyte, of Angiosperms, 459- 
463; of Cycads, 446, 446*; of 
Equisetales, 436-437; of Ferns, 
426-431; of Liverworts, 411, 
410*; of Lycopodium, 439-440; 
of Moss, 418, 418*; of Pines, 452— 
455; of Selaginella, 441, 440*. 
Spurge family, 486. 
Squash, arrangement of flowers, 27*. 
Squirting Cucumber, 88, 87*. 
Stamens, 11; described, 41, 41*. 
Staminate flower, 13; of Corn, 17, 16*, 
17*; of Pumpkin, 12*. 
Staminate strobilus, 446, 447, 447*; 
of Pines, 452, 452*, 453*. 
Standard, 23, 23*. 
Starch, as a storage product, 278; 
formation, 255; test for, 256. 
Starch grains, 256, 256*; structure, 
278, 278*. 
Starch sheath, 147, 192, 193*. 
Starchy endosperm, 64. 
Stemonitis, 337*. 
Stems, aérial, 172; branching, 167; 
characteristic features, 166; 
classes, 170; climbing, 175; erect, 
173; functions, 168; growth, 213- 
221; of Ferns, 427; of herbaceous 
Dicotyledons, 192-197; of Mono- 
