39° 
Sophora, 211, 263 
Sorbus, Mountain Ash, 211, 263, 
264, 365, 360, 372 
Sorrel Tree, Oxydendron, 212, 293 
Sour Gum, Nyssa, 212, 291, 371 
Spacing of trees, 180, 321 
Span-worms, see Inchworms 
Species, number of, 202, 206; descrip- 
tion of those in Washington, com- 
piled by B. E. Fernow, 206 
Specimen trees, planting of, 183, 
198, 208, 216, 218, 355 
Sphinxes, 157 
Spiders, 131 
Spikes (flower shapes), 325 
Spindletree, Evonymous, 192, 359 
Spiny Elm caterpillar, 163 
Spinners (moths), 158 
Spir€a, 151, 325, 328, 350, 351, 
306-371 
Spot diseases, 37 
Spraying, §5, 127, 135, 140, 141 
Spraying machinery, 138; discussion 
of in Yearbook of U. S. Dept. of 
Agriculture, 140; dealers in, 140 
note 
Springfield, Mass., cost of spraying 
in, 141 
Spruce, Picea, 16, 25, 166, 178, 189, 
193, 203, 209, 215, 228, 373; 
Blue, 242, 366; Caucasian, 243,” 
244; Japanese, 244," Norway, 
178, 240, 242; Red, 242; White, 
242, 371 
Spruce-bud tortrix, 166 
Spruce-bud worm, 166 
Spruce forests in Europe, 148 
Spurge Laurel, Daphne, 359 
Squash-bug, 150 
Stagger Bush, Pieris, 328, 338 
Staghead, 53, 61, 62, 72 
Steeplebush, Spire@a, 328, 350, 370 
Stomach of the plant, 18 
Stonebreak family, Saxifragacee, 
352 
Stool shoots, 193 
Storax family, 354 
Strawberry-bush, Calycanthus, 327, 
357, 368, 370 
Strawberry-bush, Pirus, 212, 207, 
299 
Strawberry Tree, Evonmymus, 350, 
368 
Index 
Street trees, degrees of light intensity 
needed, 25; aération, 82; height of 
crown from ground, tor; pruning 
while young, 109; spacing, 116, 
180; mechanical injuries, 117; 
guards for, 117; conditions for 
planting, 173, 176, 364; size, 178, 
364; adverse conditions, 199; con- 
siderations in choice, 201; inap- 
propriate species, 203; also 108, 
214, 226, and”List, pp. 364-365 
Siuartia, 328, 363, 370 
Siyrax, 328, 355 
Suckers, see Water-sprouts 
Suffocation, see Respiration 
Sugar Plum, see Juneberry 
Sulphur, 363 
Sulphur, Flowers of, formula, 146 
note 
Sumach, Rhus, 211, 261, 368, 370- 
372; Dwarf, 262; Osbeck, 262; 
Smooth, 262; Staghorn, 262; 
Venetian, 262 
Sun-scald, 36, 56, 59, 68, 175, 250, 286 
Sunflower, 325 
Surgery, 27, 32 
Swamp Honeysuckle, Azalea, 331 
Swamps, and root respiration, 20 
Swampy soil, trees suitable for, 371 
Sweet Fern, Myrica, 328, 362 
Sweet Gum, Liguidambar, 212, 288, 
305 
Sweet Gale, Myrica, 328, 362 
Sweet Pepperbush, Clethra, 327, 332, 
306, 370, 372 
Sweetbriar, English, 349 
Sweetleaf, Symplocos, 329, 355, 368 
Swift’s arsenate of lead, 135 xole 
Sycamore, Plaianus, 65, 69, 84, 103, 
212, 298, 299, 364, 370, 371 
Symphoricarpus, Waxberry, Indian 
Currant, Coral Berry, 329, 330, 
366, 368-370, 372 
Symplocos, Buch-Ham, Sweetleaf, 
329, 355, 308 
354, 368, 370, 371 
Tachina flies, 130 
Tamarack, 166, 230 
Tamarisk, Tamarix, 213, 316, 325, 
371, 372; French, 318 *; German, 
317 *; Indian, 319 * 
