366 American Midland Naturalist Monograph No. 7 



Sheath. The basal part of a leaf of a grass; any long and more or less 

 tubular structure surrounding an organ or part. 



Shrub. A woody plant which does not become tree-like and usually pro- 

 duces several stems from a common base. 



Simple (stem). Unbranched or without branches. (Leaf), with the blade 

 composed of one piece, not divided into separate leaflets; not com- 

 pound. (Pistil), of one carpel. 



Sinuate. With a strongly wavy margin. 



SoRUS. One of the fruit-dots or clusters of sporangia on the leaves of ferns. 



Spadix. a thick or fleshy spike of certain plants, as the Araceae, surrounded 

 or subtended by a spathe. 



Spathaceous. Resembling a spathe; spathe-bearing. 



Spathe. A large protecting bract, often colored or membranous, enclosing 

 the flower or inflorescence, especially of certain Monocotyledons. 



Spatulate. Spatula-shaped; gradually narrowed from a rounded summit. 



Spike. An indeterminate simple inflorescence with sessile flowers on an 

 elongated axis. 



Spikelet. a small spike; the unit of inflorescence of grasses and sedges. 



Spine. A sharp-pointed structure; a thorn. 



Spinescent. Becoming spiny; with short spine-like branchlets. 



Spinulose. Minutely spiny. 



Spontaneous (spont. ). Growing as native; appearing by itself without hav- 

 ing been planted. 



Sporangium. The spore-sac, especially in ferns, in which spores are produced. 



Sporocarp. a pod-like structure containing one or more sporangia, as in 

 Marsileaceae. 



Sporophyll. a specialized spore-bearing leaf, usually more or less modified 

 and unlike the normal leaves. 



Spur. A sac-like or tubular extension of some part or parts of the perianth, 

 usually nectariferous; a short branchlet with much shortened internodes, 

 usually bearing a cluster of leaves. 



Spurred. Provided with a spur. 



Squarrose. Spreading at the tip, at a right angle or more. 



Stamen. The pollen-bearing male organ of the flower. 



Staminate flower, a flower which bears stamens but no carpels. 



Staminode. a sterile stamen, or a structure resembling such and borne in 

 the staminal part of the flower; in some flowers staminodia are petal- 

 like. 



Standard. The upper broad petal of a papilionaceous flower. 



Stellate. Star-shaped; said of trichomes with radiating branches, or of a 

 cluster of radiating trichomes. 



Stigma. The part of the pistil, usually the apex, which receives pollen and 

 upon which pollen grains germinate. 



Stipe. The stalk of a pistil or similar organ. 



Stipel. a minute stipule on the petiolule of a leaflet. 



Stipitate. Having a stipe. 



Stipule. One of a pair of lateral appendages at the base of the petiole of 

 many leaves. 



Stipulate (leaf). Possessing stipules. 



Stolon. In flowering plants, a slender modified stem or basal branch trailing 

 along the ground and rooting at the nodes; a "runner." 



Stoloniferous. Bearing stolons. 



Stramineou.s. Straw-like, especially of the color of straw. 



Striate. Marked with fine longitudinal lines. 



