ductive variation, 88 1 ; sex determina- 

 tion, 897. 



Anisophylly, 608. 



Annual, 501, 714, 715. 



Annual rings, 685, 689, 690, 691. 



Annular vessels, 680, 68 i, 



Annulus, 815. 



Anther, 825, 826, 829, 830, 833, 835, 840, 

 851, 853, 854, 857, 871. 



Anthericum, stomata, 560. 



Antheridia, 817. 



Anthesis, 887. 



Anthocyan, 522, 528, 529, 571, 845, 898. 



Ant plants, 753, 754. 



Ants, 753, 754, 858. 



Aplectrum, mycorhiza, 793. 



Apogamy, 822. 



Apospory, 822. 



Apostrophe, 524. 



Apothecia, 880; 659, 800. 



Aquatic plants, 509, 609, 676, 678, 715, 719, 

 728, 810, 837, 838, 940. 



Arabis, root contraction, 504. 



Aralia, 546. 



Arbor vitae, leaf variation, 601. 



Archegonia, 817. 



Arctic plants, 733, 890, 944. 



Arid climates, 889. 



Aril, 907. 



Aristolochia, pollination, 853. 



Arm palisades, 532. 



Arrowhead, leaf variation, 590. 



Artemisia, 770. 



Artichoke, bud, 642. 



Arum, pollination, 860. 



Asarum, leaf section, 537. 



Ascocarp, 8n. 



Asexual reproduction, 809, 810, 811, 812, 

 813, 814, 75. 



Ash, twigs, 736. 



Aspidium, sporangia, 815. 



Asplenium, reproduction, 636. 



Association, plant, 939, 940, 942, 943, 944, 

 945- 



Asymmetry, 607, 734, 735. 



Atrophy, 782. 



Atropin, 626. 



Autecology, 485. 



Autoecious parasites, 764. 



Autogamy, 829, 863 (see also Close pollina- 

 tion). 



Automixis, 820. 



Autoparasitism, 786. 



Autophyte, 752. 



Autotrophic plants, 752. 



Autumn wood, 689, 690. 



Auxospore, 809. 



Awn, 924, 929. 



Azotobacter, 789. 



Bacillus, 787, 788, 790. 



Bacteria, carbohydrate synthesis, 526; in- 

 fection threads, 787, 788; parasitism, 

 762, 766; root tubercles, 787, 788, 789, 

 790; saprophytism, 754; vegetative re- 

 production, 806. 



Bacteroids, 787. 



Balanophora, parthenocarpy, 917. 



Bald cypress, 508. 



Banana, 585. 



Banyan, prop roots, 515. 



Barb, 654, 924. 



Barberry, flower, 851 ; leaf variation, 604. 



Bark, 685, 704, 708, 709. 



Bartramia, 611. 



Basidiospores, 764, 811. 



Bast fibers, 696, 699, 701. 



Beak, 921. 



Bean, regeneration, 748; root hairs, 497; 

 seed section, 905; twining, 651. 



Beech, mycorhiza, 797; seedling, 936. 



Bees, 840, 848. 



Beet, 500. 



Beetles, 842. 



Begonia, collenchyma, 697; leaf section, 



533- 



Behavior, 488. 



Berberis, flower, 851 ; leaf variation, 604. 

 Berry, 919. 

 Beta, 500. 



Betula, lenticels, 662. 

 Bicollateral bundles, 683. 

 Bidens, fruit, 924; pollen, #37. 

 Biennials, 501, 714. 

 Bifacial leaves, 629. 

 Bilabiate flowers, 829, 846, 853, 875. 

 Birch, lenticels, 662. 

 Birds, 842, 924. 

 Black knot, 784. 

 Bladder, 555, 579, 618, 619, 678. 

 Bladderwort, 618, 619, 678. 

 Blade, 521. 

 Blastophaga, 86 i. 

 Bleeding, 622. 

 Bloom, 568, 570. 

 Bog plants, 486, 537, 734, 942. 

 Boneset, cork, 705. 

 Bordered pits, 680, 690. 

 Botrychium, mycorhiza, 793. 

 Botrydium, 520. 



Box elder, flowers, #33; stem section, 685. 

 Bract, 827, 737, 829, 872. 

 Branch fall, 726. 

 Branching, 646, 647, 649. 

 Brasenia glands, 623. 

 Brassica, intumescences, 633; root hairs, 



491- 



Bridging hosts, 765. 

 Bristles, 927, 929. 



