Wedgo-roots, of Loranthus Europseus, mode 



of growth, &c., i. 211. 

 Wedge-shaped apical-cell, i. 578. 

 Weeping, of plants, explanation, i. 271. 



— in Aroid roots, i. 366. 



— of Vines, when most vigorous, 1. 270. 

 Wellingtonia. See Sequoia gigantea. 

 Welwitschia mirabilis, in habitat, ii. 727. 



geographical distribution, ii. 726. 



West-Indian Sour-sop. See A noiia muricata 

 Wettstein, and anatomical characteristics of 



hybrids, ii. 565. 

 Wheat, seeds and heat, i. 555. 



— starch, i. 459. 



White, visibility to insects, ii. 197. 

 White Hellebore. See Veyatrum. 

 White Mustard. See Sinapis alba. 

 White-thorn. See Ci-atcer/us Oxyacantha. 

 Whitlow-grass. See Draba. 

 Whorl, of perianth-leaves, i. 641. 

 Whorls, sorts of, i. 397. 

 Whortleberry, Common. See Vaccinium 



Myrtillus. 

 Wichura, hybridization of Willows, ii. 560. 

 Wigandia urens, stinging hairs, i. 441. 

 Wightia, clinging roots, i. 702, 754. 

 Wild Cress. See ^thionema. 

 Wild Pear, spines, i. 433. 

 Will-o'-the-Wisp, and luminous mycelium, i. 



503. 

 Willow. SeeSalix. 

 Willow, Gray. See Salix incana. 

 Willow-herb. See Epilobium. 

 Willows, Alpine, Tyrol, i. 524. 

 Wind, agent in spore-dispersal, ii. 812. 



— and fruit boring, i. 618. 



— and position of leaves, i. 427. 



— and seed dispersal, ii. 447. 



— and stunted growth, i. 524. 



Wind Bent-grass. See Apera spicaventi. 

 Wind-fertilized plants, characteristics, ii.l33. 

 Wind-pollination,adaptation of stigma, ii. 151. 

 Wind-witches, ii. 850. 

 Wine-cask Fungus, i. 508. 

 Wine-flower scent, ii. 202. 

 Wings of Papilionaceous flower, ii. 228. 

 Winter-buds, of Aldrovandia, i. 152. 

 Winter Cherry. See Physalis Alkekengi. 

 Winter-green. See Pyrola. 

 Winter resting of plants, i. 562. 

 Witches' Brooms and Exoasous, ii. 676. 



caused by gall-mites, ii. 548. 



cause of, ii. 518. 



on Abies pectinata, ii. 526. 



on various trees, ii. 527. 



Wolffia, rootless, ii. 745. 



Wood, ascent of sap through, i. 274. 



— changes due to attack of hyphie, i. 167. 



— longitudinal splitting in twiners and 



climbers, i. 733. 



— "luminous", i. 502. 



— of host, eilect of Langsdorfl3a on, i. 187. 

 Wood-ash, effect on Mosses, Grasses, Poly- 



gonaceous and Cruciferous plants, i. 74. 



Woodbine, Alpine. See Lonicera Alpigena. 



Wooden Pear. See Xylomelum pyriforme. 



Wood-parenchyma, i. 469. 



Woodruff. See Aspei-ula odorata. 



Wood-sorrel. See Oxalis. 



Wood-vessels and cell, views regarding func- 

 tion, i. 276. 



Woody abres, nature of, i. 726. 



Woody stem, characteristics, i. 715. 



Woolly hairs, nature of, i. 320. 



INDEX. 



Wormwood, Common. See Artemisia Ab- 



si/iithium. 

 Wormwoods, hairy covering in summer, i. 319 

 Woundwort. See Stachys. 

 Wracks. See Fucacac. 

 Wraugelia, luminosity, i. 388. 



Xanthidium aculeatum, ii. 492, 655. 

 Xanthidium octocorne, ii. 492. 

 Xanthium, protogynous, ii. 313. 

 Xantbium spinosum, and cattle, i. 451. 



fruits and dissemination, i. 615. 



hooked oapitulum, ii. 873. 



Xanthophyll, from chlorophyll, i. 372. 

 Xanthorrhea, caudex, i. 714. 



— mode of growth, i. 659. 

 Xanthorrhea hastilis, height, ii. 731. 

 Xenogamy, in hybrids, ii. 583. 



— nature of, ii. 317. 



Xeranthemum, hairy covering in summer, i 



319. 

 Xeranthemum annuum, coloured bracts, ii 



183. 

 Xylaria Hypoxylon, ii. 679. 



stroma, ii. 681. 



Xylaria polymorpha, stroma, ii. 681. 

 Xylocopa violacea and Spartium scoparium, 



ii. 267. 

 Xylomelum pyriforme, fruit, ii. 430, 431, 751. 

 protecting pericarp, ii. 449. 



9s3 



Y. 



Yakutsk, winter cold, i. 544. 



Yeast fermentation, nature of, ii. 519. 



— ferment of, i. 465. 



Yeasts. See also Saccharomyces. 



— fermentative, i. 505. 



Yellow granules of autumn leaves, i. 485. 

 Yellow-rattle. See Rhinanthiis CriMa-galli. 

 Yellow Vetchling. See LaChyrus Aphaca. 

 Yew. See Taxus baccata. 

 Ylang perfume of Zaluzianskia, ii. 242. 

 "York and Lancaster" Rose, ii. 568. 

 Yucca, aoicular leaves, i. 434. 



— and insect visits, ii. 222. 



— and night visitors, ii. 195. 



— caudex, i. 714. 



— cotyledon in germination, i. 606. 



— fertilization by Moths and advantage to 



the insects, i. 255. 



— infertility in Europe, ii. 403. 



— mode of growth, i. 660. 



— phyllotaxis, i. 402. 



- pollination by Pronuba yuccasella, ii. 157, 



245. 

 Yucca aloefolia, fertilization, ii. 158, 159. 



fertilization, geographical distribution, 



ii. 159. 

 Yucca angustifolia, pollen-grains, ii. 97. 

 Yucca gloriosa, i. 659; ii. 732. 

 Yucca Treculeana, fertilization and geo- 

 graphical distribution, ii. 159. 

 Yucca Whipplei, non-fruiting, ii. 158. 



z. 



Zftluzianikia lych!,l.!e«. pollln.tloo %tA 



Bcent, Ii. 202, Ul. 

 Zamia, cotyledon In |{«-nnln»tlon. 1 (04 



— Bpiny lenT<^, 1. 4H 

 Zannichellia, inonn-cloiu, II, 297. 



— pollen and pollltmtinn, 11. 104. 



— root origin, i. 70iV 

 Zanthoxylon, nurre ImkU. II. 31. 



Zea Mayg, and rutila^., .Mayau, IL IM. CTi. 



nionujcioiui, II. 2»7. 



protogynous. II. 313. 



Btllt-roots, niccbanlol tlaua, 1, 761. 



vitality of uptTmatopUuim. II. 94 



&c., reared In aniflci»l culture iolit. 



tion, I. 100. 

 Zero of growth, I. 561. 

 Zigzag stem, i. C58. 

 Zingil)er, venation, I. 634. 

 Zlngiljeraccas, BUnicng. 11. 73C 

 Zinnia hybrido,colour-contnut in caMVojum. 



ii. 191. 

 Zonotrichia, in watcrfiilU, L 79. 



— movement of, i. 39. 



Zooglcea, bacterial condition, ii. 621 



— of Micrococcus prodigiocui, II. 624. 

 Zoophytes, appropriaU-ne»» of name. Ii 49. 

 Zoospore, eye-spot, ii. 029. 



— of Botrj-dium, ii. &12. 



— of Vaucheria. ii. 644. 



Zoospore formation, in Hydrodlctyon. II. 641. 

 Zoosporese, ii. 606. 

 Zoospores, ii. 17. 



— behaviour towards light, i. 382. 



— of Chlorophyceiu, ii. 628. 

 Zostera, i. 77. 



— habit, &c.. i. 666. 



— pollen and pollination, 11. 104. lOS 

 Zostera marina, ii. 738. 



Zyga;na, and honey scent, ii. 207. 

 Zygnema, cell-division, i. 577. 581. 



— characteristics, ii. 658. 



— chlorophyll bodies, cf. i. 139, 373. 



— conjugation, ii. 658. 

 Zygnema pectinatum, i. 139. 

 Zygnemacete, ii. 658. 



— chromatophores, il. 654. 



— conjugation, ii. 65. 

 Zygnemeie, filaments, i. &S6. 

 Zygnemoidese, characteristics, ii. 654. 

 Zygogonium, nature of. ii. .M. 

 Zygomorphic symmetry, il. 229. 

 Zygomycetes, characteristic*, it (73. 

 Zygospore investment, in MortlercUev, 11. 674 



— of Mucor, ii. 673. 



— of Mucorini. ii. 481. 484. 

 Zygnte, nature of, ii. 54. 



— of Botrydium. ii. 042. 



— of Chlorocbytrium. ii. 637. 



— of Chlorophyccie, ii. 628. 



— of Conjugatiu, ii. 6M. 



— of Desmids, ii. 654. 



— of Hydrodlctyon. ii 641. 



— of Pediastrum, ii. 639. 



— of Phyllobiuni, i. 638. 



— of Spirogyrn, ii. 658. 



— of Volvoi globaUir, II. 635. 

 Zygotes of Ulothrix ronata, II 648. 

 Zygozoospore, formatioa, II. €32 

 Zygozoospores, of Chlorocliytrium. U. 637. 



— of Pbyllobiuui. Ii. 6JS. 



— of Stcphanosphii-ra, Jic. U. 6S1 



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UBMRY. 



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