_Silvery_, shining white or bluish-gray, usually from a silky pubescence. _Simple_, of one piece; opposed to _compound_. _Sinistrorse_, turned to the left. _Sinuate_, with margin alternately bowed inwards and outwards, 55. _Sinus_, a recess or bay; the re-entering angle between two lobes or projections. _Sleep of Plants_ (so called), 151. _Smooth_, properly speaking not rough, but often used for glabrous, i. e. not pubescent. _Soboliferous_, bearing shoots (_Soboles_) from near the ground. _Solitary_, single; not associated with others. _Sordid_, dull or dirty in hue. _Sorediate_, bearing patches on the surface. _Sorosis_, name of a multiple fruit, like a pine-apple. _Sorus_, a fruit-dot of Ferns, 159. _Spadiceous_, chestnut-colored. Also spadix-bearing. _Spadix_, a fleshy spike of flowers, 75. _Span_, the distance between the tip of the thumb and of little finger outstretched, six or seven inches. _Spathaceous_, resembling or furnished with a _Spathe_, a bract which inwraps an inflorescence, 75. _Spatulate_, or _Spathulate_, shaped like a spatula, 52. _Species_, 175. _Specific Names_, 179. _Specimens_, 184. _Spermaphore_, or _Spermophore_, one of the names of the placenta. _Spermum_, Latin form of Greek word for seed; much used in composition. _Spica_, Latin for spike; hence _Spicate_, in a spike, _Spiciform_, in shape resembling a spike. _Spike_, an inflorescence like a raceme, only the flowers are sessile, 74. _Spikelet_, a small or a secondary spike; the inflorescence of Grasses. _Spine_, 41, 64. _Spindle-shaped_, tapering to each end, like a radish, 36. _Spinescent_, tipped by or degenerating into a thorn. _Spinose_, or _Spiniferous_, thorny. _Spiral Vessels_ or _ducts_, 135. _Spithameous_, span-high. _Spora_, Greek name for seed, used in compound words. _Sporadic_, widely dispersed. _Sporangium_, a spore-case in Ferns, &c., 158. _Spore_, a body resulting from the fructification of Cryptogamous plants, in them the analogue of a seed. _Spore-case_ (_Sporangium_), 158. _Sporocarp_, 162. _Sport_, a newly appeared variation, 176. _Sporule_, same as a spore, or a small spore. _Spumescent_, appearing like froth. _Spur_, any projecting appendage of the flower, looking like a spur but hollow, as that of Larkspur, fig. 239. _Squamate_, _Squamose_, or _Squamaceous_, furnished with scales (_squamæ_). _Squamellate_, or _Squamulose_, furnished with little scales (_Squamellæ_, or _Squamulæ_). _Squamiform_, shaped like a scale. _Squarrose_, where scales, leaves, or any appendages spread widely from the axis on which they are thickly set. _Squarrulose_, diminutive of _squarrose_; slightly squarrose. _Stachys_, Greek for spike. _Stalk_, the stem, petiole, peduncle, &c., as the case may be. _Stamen_, 14, 80, 98. _Staminate_, furnished with stamens, 86. _Stamineal_, relating to the stamens. _Staminodium_, an abortive stamen, or other body in place of a stamem.