INDEX 



Vervain, hairs, 623. 



Vessels, 670, 680, 68 1 ; annular, 680, 68 1 ; 



latex, 721; pitted, 68 1; reticulated, 680 ; 



scalariform, 679, 680; spiral, 680, 681. 

 Vestibule, 555, 556, 574. 

 Viburnum, leaf gall, 781; shoots, 644. 

 Vicia, root hairs, 491. 

 Viola ; violet, leaf section, 530. 

 Virginia creeper, pendulous stem, 657. 

 Vitalism, 948. 

 Vitality, seed, 908, 923. 

 Vitis, gall, 576; habit, 655. 

 Vivipary, 930, 931. 



Wall, dorsal, 555, 556, 55$, 562; ventral, 

 555, 556, 562. 



Wandering Jew, crystals, 625. 



Wasp, fig, 86 1. 



Waste, accumulation of, 623, 624, 625, 626, 

 718, 723, 724, 725. 



Water, 565 ; absorption, 491, 493, 517, 518, 

 565, 608, 614, 615; accumulation, 627, 

 628, 629, 630, 631, 632, 633, 718; calyx, 

 845; dispersal, 922, 926; exudation, 620, 

 622; hyacinth, 510; leaf form and, 599; 

 leaves, 590, 592, 593, 595, 837 ; lenticels, 

 663; lily, 540, 561; net, 810; parasites, 

 762, 771 ; plants, 609, 676, 678 (see also 

 Hydrophytes); pollination, 837; reten- 

 tion, 627; roots, 509, 510, 610; roots 

 and, 499, 502, 503, 504, 505, 506; shield, 

 623; stem elongation and, 727 ; stomata, 

 620, 621; synthesis and, 527; tissue, 

 533* 629, 630, 631, 632 ; vascular de- 

 velopment and, 686. 



Waterweed, vascular bundle, 687. 



Wax, 568, 570; plant, 697. 



Wheat, grain section, 915; root hairs, 492,- 

 rust, 813. 



Willow, epidermis, 570; habit, 584; 

 polarity, 749; roots, 503. 



Wind dispersal, 920, 926; pollination, 833, 

 834, 835, 837, 838. 



Winged fruits, 921. 



Winter bud, 555, 572, 646, 678, 736, 936, 

 Q38. 



Witches' brooms, 783. 



Withered leaves, 581. 



Wolffia, 678. 



Wood, autumn, 689, 690 ; fibers, 697 ; 

 secondary, 684, 685, 689, 690 ; spring, 

 689, 690 ; waste accumulation in, 725. 



Woolly hairs, 572, 573, 574. 



Wound cork, 707. 



Xanthic colors, 845. 



Xanthium, fruit, 924; fruit section, 932. 



Xanthophyll, 522. 



Xenogamy, 829 (see also Cross pollination). 



Xerophile, 487. 



Xerophytes, 486, 939, 943 ; absorption, 

 613; associations, 943, 944; bog, 486, 

 537, 942; chlorenchyma, 532, 533; con- 

 genital, 951; cutinization, 568; dwarfs, 

 733 ; facultative, 951 ; leaf sections, 533, 

 535, 567, 581, 598, 629, 630, 631, 639, 

 724; leaves, 570, 578 ; obligate, 951 ; 

 reaction, 951; roots, 505, 506, 507; salt 

 marsh, 486, 942 ; stomata, 557, 55$, 561 ; 

 succulence, 627, 628, 629, 630, 631, 635; 

 wax coats, 570. 



Xylem, 530, 630, 680, 682, 683, 684, 685; 

 secondary, 684, 685. 



Xylocentric bundles, 683. 



Yarrow, flowers, 846. 



Yucca, flowers, 871; habit, 588; pollina- 

 tion, 864. 



Zea, prohydrotropism, 499; prop roots, 



5/4,- roots, 494. 

 Zebrina, crystals, 625. 

 Zoogloea, 787. 

 Zoospores, 810, 817. 

 Zygadenus, roots, 505. 

 Zygomorphy, 841, 843, 846, 853, 859. 

 Zygospore, 816. 



