_Syringa_, 199; Fig. 111. See also "Lilac." Tamarack, 142. Tap-root, 131, 173. _Taraxacum_. See "Dandelion." _Taxodium_. See "Cypress." _Taxus_. See "Yew." Teasel, 224; Fig. 124. _Tecoma_. See "Trumpet-creeper." Teleuto-spore, 80, 81. Tendril, 171. _Terebinthinæ_, 198. Tetraspore, 51, 52. Thistle, 173, 223; Fig. 125. Thorn, 172. Thyme, 215. _Thymeleaceæ_, 206. _Thymelinæ_, 206. _Tilia_, _-aceæ_. See "Linden." _Tillandsia_, 156; Fig. 84. Tissue, 8. Tissue system, 115. Toadstool, 82. Tobacco, 215. _Tolypella_, 40. Tomato, 215. Touch-me-not. See "Jewel-weed." Tracheary tissue, 110, 121, 177. Tracheid, 110, 138. _Tradescantia_. See "Spiderwort." Trailing arbutus, 211. _Tremella_, 81; Fig. 51. _Trichia_, 13, 14; Fig. 5. Trichogyne, 51. _Tricoccæ_, 199. _Triglochin_. See "Arrow-grass." _Trillium_, 146, 154, 155; Fig. 83. _Triphragmium_, 81. _Tropæolum_. See "Nasturtium." Trumpet-creeper. Tuber, 120, 153, 172. _Tubifloræ_, 213. Tulip, 146. Tulip-tree, 187; Fig. 100. Turnip, 192. Twin-leaf, 187; Fig. 101. _Typha_, _-aceæ_. See "Cat-tail." _Ulmaceæ_. See "Elm." _Ulva_. See "Sea-lettuce." _Umbelliferæ_. See "Umbel-wort." Umbel-wort, 202. _Umbellifloræ_, 202. _Uredineæ_, 77. _Uromyces_, 81; Fig. 47. _Urticinæ_, 183. _Usnea_, 75; Fig. 45. _Ustillagineæ_. See "Smut." _Ustillago_, 65; Fig. 38. _Utricularia_. See "Bladder-weed." _Uvularia_. See "Bellwort." _Vaccinium_. See "Cranberry." Vacuole, 8. Valerian, 224; Fig. 124. _Valeriana_, _-eæ_. See "Valerian." _Vallisneria_. See "Eel-grass." _Vanilla_, 166. _Vaucheria_, 34-37; Figs. 21, 22. structure of plant, 35. _racemosa_, 35. non-sexual reproduction, 36. sexual organs, 36. fertilization, 36. resting spores, 37. Venus's fly-trap, 192. _Verbascum_. See "Mullein." _Verbena_, _-aceæ_, 218; Fig. 121. _Veronica_, 217; Fig. 120. Vervain. See "_Verbena_." Vessel, 121, 135, 150, 175, 177. _Viburnum_, 223; Fig. 124. _Victoria regia_, 190. _Vinca_. See "Periwinkle." Vine, 199. Violet, 192; Fig. 104. _Viola_, _-aceæ_. See "Violet." Virginia creeper, 171, 199. _Vitis_. See "Grape." _Vitaceæ_. See "Vine." _Volvox_, 12, 20; Fig. 10. _Volvocineæ_, 12, 19. Wall-flower, 192. Walnut, 183. Wandering-Jew, 157. Water fern, 117. Water-leaf, 214; Fig. 118. Water-lily. See "_Nymphæa_," "_Castalia_." Water-milfoil, 206; Fig. 113. Water mould. See "_Saprolegnia_." Water net, 24; Fig. 11. Water-plantain, 167. Water-shield, 190. Water-starwort, 200. Wax-plant, 220. Wheat, 78. Wheat rust, 78, 81; Fig. 47. _Whitlavia_, 214. Wild ginger, 224; Fig. 126. Wild onion, 230. Wild parsnip, 202. Willow, 181-183; Fig. 96. Willow-herb, 206, 226; Fig. 113. Wing (of papilionaceous flower), 208. Wintergreen, 211. _Wolffia_, 159. Wood. See "Xylem." Wood-sorrel, 197; Fig. 107. Xylem, 110, 124, 135, 150, 173, 176. Yam, 154. Yeast, 63, 64; Fig. 37. cause of fermentation, 63. reproduction, 64. systematic position, 64.