t. See "Spermaphyte."

_Selaginella_, _-eae_. See "Smaller club-moss."

Sensitive-brier, 209; Fig. 115.

Sensitive-plant, 209.

Sepal, 148, 150, 174, 179.

_Sequoia_. See "Red-wood."

Sessile leaf, 170.

_Shepherdia_, 206.

Shepherd's-purse, 173-180; Figs. 93-95.
gross anatomy of stem, 173.
leaf, 124, 173.
root, 173.
branches, 174.
flower, 174, 175.
fruit and seed, 175.
histology of root, 175, 176.
stem, 177.
leaf, 177, 178.
development of flower, 179.
ovule, 179.
embryo, 180.

Shooting-star, 212; Fig. 117.

Sieve-tube, 111, 137.

_Silene_. See "Catch-fly."

Silicon, 2.

Simple leaf, 170.

_Siphoneae_, 22, 34.

_Sisyrinchium_. See "Blue-eyed grass."

Skunk cabbage, 157.

Slime mould, 12, 14; Fig. 5.
plasmodium, 12.
movements, 13.
feeding, 13.
spore-cases, 13.
spores, 13.
germination of spores, 14.

Smart-weed. See "_Polygonum_."

_Smilaceae_, 155.

Smoke-tree, 198.

Smut, 64, 65.

Smut-corn. See "_Ustillago_."

Snowberry, 223.

Soft-tissue, 112.

_Solanum_, _-eae_, 215.

Solomon's Seal, 154; Fig. 83.

Soredium, 74.

Sorus, 118.

_Spadiciflorae_, 153, 157.

Spadix, 157.

Spanish bayonet. See "_Yucca_."

_Sparganium_. See "Bur-reed."

Speedwell. See "_Veronica_."

Spermaphyte, 128-129.

Spermatozoid, 28, 36, 40, 46, 51, 89, 96, 106, 122.

Spermagonium, 79, 80.

_Sphagnum_, _-aceae_, 99, 100.
sporogonium, 100.
leaf, 100.

Spice-bush, 188.

Spiderwort, 6, 151, 157; Fig. 85.

_Spigelia_. See "Pink-root."

Spike, 181.

Spikenard, 202; Fig. 110.

Spinach, 184.

Spindle-tree, 199; Fig. 109.

_Spirogyra_, 30-32; Fig. 18.
structure of cells, 30.
starch, 31.
cell-division, 31.
sexual reproduction, 32.

Sporangium, 55, 62, 113, 121, 122, 131, 148, 151, 179.

Spore-case. See "Sporangium."

Spore-fruit, 51, 66, 69, 70, 73, 83.

Spore-sac. See "Ascus."

Sporocarp. See "Spore-fruit."

Sporogonium, 87, 90, 102, 123.

Sporophyll, 128, 131, 148.

Sporophyte, 109.

Spring-beauty, 185; Fig. 98.

Spruce, 142.

Spurge. See "_Euphorbia_."

Squash, 221.

Staining agents, 4, 231, 233.

Stamen, 128, 143, 148, 174, 179.

Standard, 207.

_Staphylea_. See "Bladder-nut."

Starch, 31, 95, 152.

_Statice_. See "Sea-rosemary."

_Stellaria_. See "Chick-weed."

_Stemonitis_, 13; Fig. 5.

_Sticta_, 75; Fig. 45.

_Stigeoclonium_, 26; Fig. 14.

Stigma, 145, 148, 175, 179.

St.