GENUS 7. 



SEDGE FAMILY. 



329 



6. Scirpus subterminaiis Torr. Water Club- 

 rush. Fig. 806. 



Scirpus subterminaiis Torr. Fl. U. S. i : 47. 1824. 



Perennial, aquatic, culms slender, terete, nodulose, 

 i-3i long. Leaves very slender, channeled, 6'-2 long, 

 i"-J" w ide; spikelet solitary, terminal, oblong-cylindric, 

 narrowed at each end, several-flowered, 3" -7" long, sub- 

 tended by a subulate erect involucral leaf, i'-2i' long, 

 thus appearing lateral; scales ovate-lanceolate, acute, 

 membranous, light brown with a green midvein ; bristles 

 about 6, downwardly barbed, as long as the achene or 

 shorter; stamens 3; style 3-cleft to about the middle; 

 achene obovoid, 3-angled, dark brown, smooth, rather 

 more than i" long, obtuse, abruptly beaked by the slen- 

 der base of the style. 



In ponds and streams or sometimes on their borders, New- 

 foundland to the Northwest Territory and British Columbia, 

 South Carolina, Pennsylvania, Michigan and Idaho. The 

 so-called variety terrestris is an emersed form with erect 

 culms and shorter spikelets. July-Aug. 



7. Scirpus Hallii A. Gray. Hall's Club-rush. Fig. 807. 



Scirpus Hallii A. Gray, Man. Ed. 2, Add. 1863. 



5". supinus var. Hallii A. Gray, Man. Ed. 5, 563. 1867. 



Annual, culms very slender, smooth, tufted, ob- 

 tusely triangular, erect, striate, 5'-i2' tall. Lower 

 sheaths oblique, and acuminate or mucronate on one 

 side, the upper one commonly bearing a filiform blade, 

 '-2*' long; spikelets capitate in clusters of 1-7, 

 oblong-cylindric, obtuse, many-flowered, 3" -6" long, 

 about i" thick, appearing lateral by the extension of 

 the solitary involucral leaf which is i'-4' long; scales 

 ovate-lanceolate, light greenish brown, acuminate, 

 keeled, cuspidate by the excurrent tip of the midvein; 

 bristles wanting ; stamens mostly 2 ; achene obovate- 

 orbicular or slightly broader than high, black, plano- 

 convex, mucronulate, strongly wrinkled transversely, 

 about \" in diameter. 



In wet soil, Massachusetts to Florida, west to Illinois, 

 Colorado, Texas and Mexico. Also in eastern Asia. The 

 lowest sheaths occasionally subtend a flower with very 

 long styles. July-Sept. 



8. Scirpus debilis Pursh. Weak-stalked Club- 

 rush. Fig. 808. 



Scirpus debilis Pursh, Fl. Am. Sept. 55. 1814. 

 Scirpus Smithii A. Gray, Man. Ed. 5, 503. 1867. 



Annual, smooth, culms slender, obtusely triangular 

 or nearly terete, tufted, erect or ascending, 6'-2 high. 

 Sheaths obliquely truncate, the upper one rarely bear- 

 ing a short subulate blade; spikelets capitate in clus- 

 ters of 1-12, ovoid-oblong, subacute, many-flowered, 

 appearing lateral, the solitary involucral leaf nar- 

 rowly linear, 1^-4' long, erect or divergent; scales 

 light yellowish-brown with a green midvein, broadly 

 ovate, obtuse or acute; bristles 4-6, downwardly barb- 

 ed, somewhat unequal and about as long as the achene 

 or short or wanting; stamens 2-3; style 2-cleft or 

 rarely 3-cleft; achene plano-convex, broadly obovate 

 or orbicular, smooth or slightly roughened, dark brown, 

 shining, obtuse, mucronulate. 



In wet soil. Maine to Ontario, Minnesota, Georgia, 

 Alabama and Nebraska. July-Sept. 



