304 CONTRIBUTIONS FROM THE NATIONAL. HERBARIUM. 



Sheath. The lower tubular part of a leaf inclosing the stem, especially in grasses 



and sedges. 

 iShoot. A stem with its leaves and other appendages. 

 Silique. The peculiar long two-valved capsule of the Braesicaceae. 

 Silky. See sericeous. 

 Simple. Undivided; not compound. 

 Sinuate. With the outline of the margin strongly wavy. 

 Sinus. The angle between two lobes. 



Smooth. Unarmed; without roughness due to spines, tubercles, or coarse outgrowtlii 

 Sorus. A group or cluster of sporangia, as in the ferns. 

 Spadix. A spike with a fleshy axis. 

 Spathe. One or more large bracts subtending or inclosing an inflorescence, espo 



cially a spadix. 

 Spatulate. Gradually narrowed downward from a rounded apex. 

 Spicate. Spikelike or arranged in a spike. 

 Spike. An elongate inflorescence or branch of an inflorescence with the flowers 



sessile or nearly so. 

 Spikelet. A small or a secondary spike, particularly as applied to the flower 



clusters of grasses and sedges. 

 Spine. A rigid sharp-pointed outgrowth of a plant, being a modified stem or leaf. 

 Spinulose. Minutely spiny; applied loosely also to margins with variously awned 



teeth. 

 Sporangium. A spore case. 

 Sporophyll. The leaf subtending the sporangium in certain of the fern allies, or the 



specialized spore-bearing leaf parts as a whole. 

 Spreading. Diverging nearly at right angles. 

 Spur. A hollow, saclike or tubular extension of a floral organ. 

 Squarrose. Having the parts or appendages wide-spreading. 

 Stamen. The organ of a flower which bears the pollen grains. 

 Staminate. Stamen-bearing. 



Staminodium.. A sterile stamen, or any similar sterile structiue corresponding to it. 

 Staiidard. The broad upper petal of a papilionaceous corolla, as, for example, in a 



pea blossom. 

 Stellate. Star-shaped, the slender segments or divisions radiating from a common 



center. 

 Stem. The main leafy axis of a plant. 



Sterile. \Yithout functioning reproductive organs; in the ferns, without sporangia. 

 Stigmxi. The tip or other part of a pistil through which fertilization by the pollen 



grains is accomplished. 

 Stipe. The stalklike support of an organ or part; more especially, the leaf stalk 



of a fern. 

 .Stipitate. Distinctly stalked; provided with a stipe. 

 Stipulate. Having stipules. 

 Stipule. One of a pair of appendages borne at the base of certain petioles, or these 



sometimes united. 

 Stolon. A trailing basal branch rooting at the nodes. 

 Stoloniferous. Producing stolons. 

 Stramineous. Straw-colored. 

 Striate. Minutely grooved or furrowed. 

 Strict. Perfectly straight and upright. 

 Strigose. Beset with appressed straight stiff hairs. 



Style. The usually slender portion of the pistil connecting the stigma with the ovary. 

 Sub-. A Latin prefix, usually signifying somewhat, slightly, or nearly. 

 Subacute. Acutish; somewhat acute. 



