318 



BRITISH PLANTS 



229, 272 ; birch, 229, 271 ; de- 

 ciduous, 265, 270 ; evergreen 

 coniferous, 230, 265, 273 ; ground- 

 veg. of, 266 ; larch-, 274 ; natural, 

 267 ; oak-, 229, 269 ; pine, 273 ; 

 scar-, 269 



Wood-sorrel. See Oxalis 



Wormwood, 42 



Wounds, 140 



Xerophilous tropophytes, 58, 62 

 Xerpphytes, 29, 30, 36, 74, 77, 89 ; 

 air-spaces in, 40 ; palisade-tissue 

 in, 41, *72 ; cuticle of, 40 ; 

 development of hairs and scales 

 in, 39, of sclerenchyma in, 41, 

 *43 ; evergreen-, 39 ; mucilage in, 

 *41 ; position of leaves in, 46 ; 

 size of leaves in, *39 ; oil in, 42 ; 

 water-storing tissue in, 41 

 Xerophytie annuals, 59 ; chars., 30, 

 36, 58, 60, 61 ; conditions, 33, 



effect on form of leaf, 38, of stem, 

 36 ; factors, 32, 35 ; forms of leaf 

 and shoot, 42 ; structures in 

 leaves, 39, 40 ; regions, 35, 77, 89 ; 

 tendencies, 39 

 Xylem, *45 ; in aquatics, 49 



Yellow bird's-nest (see Monotropa) ; 



rattle (see Rliinanthus] ; water-lily 



(see Nuphar) 

 Yew : leaf -mosaic, 68 ; succulent 



seeds, 196 ; Irish, origin of, 205 

 Yucca, 133 



Zannichellia, 55 



Zea Mais, 147, 148 



Zones, 226 



Zoning : of aquatics, 236 ; of the 

 reed-swamp, 242 ; of seashore pis., 

 278, 283 ; of seaweeds, 276 



Zostera: leaf, 50; pollination, 166, 

 276 



