378 
Sperm cells, *165, 224-285*. 
Sperm nucleus, 166. 
Spike, App. I, *858. 
Spine, 123-125*. 
Spirogyra, type study, 219-223*. 
Sporangium, *281. 
Spore, 211, *221, *226, *236, *237, 
*248, #249, *251, *253, *256, *257, 
*262, *281, *297, #801. 
Spore-capsules, ¥271, #273. 
Spore-cases, *281, *301. 
Spore-plants, 210-294*. 
Spore-plants, classes of, 210. 
Sporophyll, 286, 302, 307. 
Sporophyte, *273, *275, #281, *284, 
*286, *289. 
Spruce, fertilized ovule of, #302. 
Squash seed, 4-5*, 
Squash seed, section, *5. 
Squash seedling, 23, 24. 
Stamen, *148, *153. 
Stamen, parts of, #153. 
Standard, *150. 
Starch, 15-18*, 82, 138-140. 
Starch disappears during germina- 
tion, 18. 
Starch food for man, 333, 334. 
Starch in leaves, 138, 189. 
Starch, testing seed for, 15, 16. 
Stem, 49-85*, 
Stem, definition of,.49. 
Stem, dicotyledonous, annual, gross 
structure of, 67-69%. 
Stem, dicotyledonous, minute struc- 
ture of, 69, 70. 
Stem, early history of, *71. 
Stem, functions of cells of, 77, 78. 
Stem, monocotyledonous, *65, 66, 
67. 
Stem, structure of, 65-74*. 
ESSENTIALS OF BOTANY 
Stem-structure, early history of, 71- 
73*, 
Stemless plants, *55, 56. 
Stems, 49-85*. 
Stems, climbing, *56, *57, 58. 
Stems, storage of food in, 82-85. 
Stems, twining, *57, 58. 
Sterigmata, *262. 
Sterilization, 241-243. 
Stigma, *154. 
Stigma, structure of, *164, *165. 
Stinging hair, *126. 
Stipe, *228, 229. 
Stipules, *100, *101. 
Stomata, *128, #129, 130, 182, 138. 
Stomata, operation of, 182, 133. 
Stone-fruit, *187. 
Storage of food in the root, 37-39. 
Storage of food in the stem, 82, 83. 
Strawberry, *189. 
Struggle for existence, 200-205. 
Style, *153, *165. 
Sugar, 11. 
Sugar beet, breeding, 311-313. 
Sugar, food for man, 334, 335. 
Sugar, formed during germination, 
11. 
Sundew, 119-121*. 
Superior, 155, *156. 
Supernumerary buds, 89. 
Survival of the fittest, 205, 206. 
Sweet pea, flowers, *150. 
Symmetry of flowers, 150. 
Sympetalous, 151. 
Synsepalous, 151. 
Tangelo, *820. 
Tanning materials, 340. 
Taper-pointed, App. I, *356. 
Taproot, *34. 
