264 CYPERACEAE. 



7. Scirpus Hallii A. Gray. Hall's Club-rush. (Fig. 615.) 



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

 Scirpus supinus var. Hallii A.. Gray, Man. Ed. 5, 563. 

 1867. 



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

 tusely triangular, erect, striate, $'-12' 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 \" 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 ex- 

 current 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 

 Y*" in diameter. 



In wet soil, Massachusetts to Florida, west to Illinois, Colorado, Texas and Mexico. The lowest 

 sheaths occasionally subtend a flower with very long styles. July-Sept. 



8. Scirpus debilis Pursh. Weak-stalked Club-rush. (Fig. 616.) 



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



Annual, smooth, culms slender, terete or nearly 

 so, tufted, erect or ascending, 6 / -2 high. Sheaths 

 obliquely truncate, the upper one rarely bearing a 

 short subulate blade; spikelets capitate in clusters 

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

 appearing lateral, the solitary involucral leaf nar- 

 rowly linear, i^ / ~4 / long, erect or divergent; 

 scales light yellowish-brown with a green midvein, 

 broadly ovate, obtuse or acute; bristles 4-6, 

 downwardly barbed, somewhat unequal and about 

 as long as the achene; stamens 2-3; style 2-cleft or 

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

 ovate or orbicular, smooth or slightly roughened, 

 dark brown, shining, obtuse, mucronulate. 



In wet soil, Maine to Minnesota, south to Georgia, 

 Alabama and Nebraska. July-Sept. 



^f ^/ 



9. Scirpus Smithii A. Gray. Smith's 

 Club-rush. (Fig. 617.) 



Scirpus Smilhii A. Gray, Man. Ed. 5, 563. 1867. 



Annual, similar to the preceding species, but the 

 culms usually lower and more slender or nearly fili- 

 form, 3 / -i2 / tall, the sheaths oblique and acumi- 

 nate or the upper one bearing a subulate blade. 

 Spikelets 1-4, in an apparently lateral cluster, 

 ovoid, acute, 2"-$" long, the involucral leaf very 

 narrow, elongated, erect; scales oblong, obtuse, 

 mucronulate, pale brown with a narrow, green mid- 

 vein; bristles usually wanting, sometimes 1-3, and 

 very much shorter than the achene; style 2-cleft; 

 achene plano-convex, obovate or orbicular, brown, 

 rather dull, smooth or minutely roughened, obtuse, 

 mucronulate. 



In wet muddy places, Vermont to Minnesota, south 

 to Delaware, Pennss'lvania and Michigan. Perhaps 

 only a form of the preceding. July-Sept. 



