304 CONTRIBUTIONS FROM THE NATIONAL HERBARIUM. 



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



and sedges. 

 Shoot. A stem with its leaves and other appendages. 

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

 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 outgrowths 

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

 Spadir. A spike with a fleshy axis. 



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

 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. 

 S pikelet. 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 structure corresponding to it. 

 Standard. 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. Without functioning reproductive organs; in the ferns, without sporangia. 

 Stigma. 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. 

 Stoloni/erous. 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. 



