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MISC. PUBLICATION 200, U. S. DEPT. OF AGRICULTURE 



Rhizomatous. Having rhizomes or appear- 

 ing like rhizomes, as the base of a decum- 

 bent stem. 



Rosette. A cluster of spreading or radiating 

 basal leaves, as in the overwintering stage 

 of Panicum, sect. Dichanthelium. 



Rudiment. An imperfectly developed organ 

 or part. Rudimentary. Underdeveloped. 

 Applied also to one or more rudimentary 

 florets at the summit of the spikelet of 

 some genera, as Melica, Bouteloua, Chloris. 



Rugose. Wrinkled. Said especially of the 

 fruit of some species of Panicum and 

 allied groups. 



Saccate. Bag or sac-shaped, as the second 

 glume of Sacciolepis. 



Scabrous. Rough to the touch. Covered with 

 minute points, teeth, or very short stiff 

 hairs. Scaberulous. Minutely scabrous. 



Scale. The reduced leaves at the base of a 

 shoot. Said especially of the reduced or 

 rudimentary leaves on a rhizome. 



Scarious. Thin, dry, and membranaceous, 

 not green. 



Secondary. Subordinate; below or less than 

 primary. Said of branches arising from 

 primary branches. 



Secund. One-sided or arranged along one 

 side. 



Self -pollinated. Pollinated in the bud or by 

 pollen from the same flower. The opposite 

 of cross-pollinated. 



Serrate. Saw-toothed; having sharp teeth. 

 Serrulate. Minutely serrate. 



Sessile. Without a pedicel or stalk. The 

 opposite of pediceled. Said of blades, 

 spikelets, and other organs. 



Setaceous. Bristlelike. Said especially of 

 slender teeth attenuate to an awn. 



Sheath. The lower part of a leaf that encloses 

 the stem. 



Sinuous. Wavy. 



Smooth. Not rough to the touch. Compare 

 glabrous, without hairs but which may be 

 rough to the touch. 



Spathe. A sheathing bract of the inflores- 

 cence found especially in the Andropo- 

 goneae. 



Spike. An unbranched inflorescence in which 

 the spikelets are sessile on a rachis. Spike- 

 like. A dense panicle in which the pedicels 

 and branches are short and hidden by the 

 spikelets as in Phleum. 



Spikelet. The unit of the inflorescence in 

 grasses, consisting of two glumes and one 

 or more florets. 



Spreading. Having an outward direction. 

 Said especially of the branches of a 

 panicle when they lie between ascending 

 and the horizontal direction (right angles). 



Squarrose. Spreading or recurved at the tip. 

 Said of the tips of lemmas. 



Stamen. The part of the flower that bears the 

 pollen. Staminate. Containing stamens 

 only. Also applied to an inflorescence or a 

 plant with staminate flowers. 



Sterile. Without pistils. A sterile floret may 



be staminate or neuter. It may even lack a 



palea, and consist of nothing but a lemma. 

 Stipe. A minute stalk to an organ. Applied 



especially to a pistil. Also sometimes to the 



prolongation of a rachilla as in Calama- 



grostis. Stipitate. Having a stipe. 

 Stolon. A modified propagating stem above 



ground creeping and rooting or curved 



over and rooting at the tip. Stoloniferous. 



Bearing stolons. 

 Stramineous. Straw-colored, pale yellow. 

 Striate. Marked with fine parallel lines or 



minute ridges 

 Strict. Stiffly upright. 

 Strigose. Rough with short stiff hairs; 



harshly pubescent. 

 Sub-. A prefix to denote somewhat, slightly, 



or in a less degree; as subacute, somewhat 



acute. 

 Subtend. To be below, as a bract subtends a 



branch in its axil. 

 Subulate. Awl-shaped. 

 Succulent. Fleshy or juicy. 

 Sulcate. Grooved or furrowed. Said chiefly 



of stems, sheaths, and slender blades. 

 Tawny. Pale brown or dirty yellow. 

 Teeth. Pointed lobes or divisions. 

 Terete. Cylindric and slender, as the usual 



unflattened stems or culms of grasses. 

 Tessellate. The surface marked with square 



or oblong depressions. 

 Triad. A group of 3, applied to the central 



and 2 lateral spikelets in Hordeum and 



to ultimate racemes in Sorghum. 

 Trifid. Divided into three parts as the awns 



of Aristida. 

 Truncate. Ending abruptty, as if cut off 



horizontally. 

 Tuber culate. Furnished with small projec- 

 tions. 

 Turgid. Swollen, as the pulvini of a panicle 



during anthesis. 

 Unilateral. One-sided or turned to one side. 

 Unisexual. Said of flowers containing onty 



stamens or onh r pistils. 

 Verticillate. In verticils or whorls. 

 Villous. Pubescent with long soft hairs. 

 Virgate. Straight and erect; wand-shaped. 

 Web. The cluster of slender soft hairs at the 



base of the floret in certain species of Poa. 

 Whorl. A cluster of several branches around 



the axis of an inflorescence. 

 Wing. A thin projection or border; for 



example, the thin borders on the rachis of 



certain species of Digitaria and Paspalwn. 



APPENDIX 



The following genera are additions to or 

 changes from the genera in the first edition 

 of the Manual, and which are not in Hitch- 

 cock's Genera of Grasses of the United 

 States (United States Department of Agri- 

 culture Bulletin 772, revised edition, 1936.) 

 The place of publication and the type species 

 are here given, the descriptions being given 

 in the text. 





