262 



CYPERACEAE 



Achene smooth or merely papillose or reticulated. 

 Fibrous-rooted annual. 

 Perennial by rootstocks or stolons. 



Tubercle depressed, nearly flat; achene smooth. 

 Tubercle conic or subulate. 



Rootstock very stout, with scarious scales 2-3 cm. long. 

 Rootstocks slender, nearly naked. 



Spikelet nearly linear; tubercle conic-subulate. 

 Spikelet oblong; tubercle conic. 



Achene finely rigid-reticulate or nearly smooth. 

 Achene papillose. 

 Tubercle continuous with the achene. 



9. E. disciformis. 



10. E. bolandcri. 



11. E. dccumbens. 



12. E. parishii. 



13. E. montana. 



14. E. acuminata. 



15. E. rostcUata. 



1. Eleocharis caribaea (Rottb. ) Blake. 

 Capitate Spike-rush. Fig. 624. 



Scirpits caribaeus Rottb. Descr. 24. 1772. 

 Scirpus capitatus L. Sp. PI. 48. 1753. 

 Eleocharis caribaea Blake, Rhodora 20: 24. 1918. 



Annual ; roots fibrous ; culms densely tufted, nearly 

 terete, almost filiform, 5-25 cm. tall. Upper sheath 

 1-toothed; spikelet ovoid, obtuse, much thicker than the 

 culm, 3-5 mm. long, 2-3 mm. thick, many-flowered ; 

 scales broadly ovate, obtuse, finn, pale or dark brown 

 with a greenish midvein, narrowly scarious-margined, 

 persistent; stamens mostly 2; style 2-cleft; bristles 5-8, 

 slender, downwardly hispid, as long as the achene; 

 achene obovate, jet black, smooth, shining, iiearly 1 mm. 

 long; tubercle depressed, apiculate, constricted at the 

 base, very much shorter than the achene. 



Moist grounds, Sonoran Zones; Riverside and San Bernar- 

 dino Counties, California; east to Indiana, Maryland and Flor- 

 ida; West Indies; Mexico; tropical continental America and 

 Old World tropics. Type locality: St. Croi.x. The specific 

 name capitatus has long been erroneously applied to this 

 species. 



2. Eleocharis atropurpurea ( Retz. ) Kunth. 

 Purple Spike-rush. Fig. 625. 



Scirpjis atropurpurens Retz. Obs. 5: 14. 1789. 

 Eleocharis atropurpurea Kunth, Enum. 2: 151. 1837. 



Annual; roots fibrous; culms tufted, very slender, 

 2-9 cm. high. Upper sheath 1-toothed; spikelet ovoid, 

 many-flowered, subacute. 3-4 mm. long, 2 mm. in 

 diameter or less; scales minute, ovate-oblong, persistent, 

 purple-brown with green midvein and very narrow 

 scarious margins; stamens 2 or 3 ; style 2-3-cleft; 

 bristles 2-4, fragile, white, minutely downwardly hispid, 

 about as long as the achene; achene jet black, shining, 

 0.5 mm. long, smooth, lenticular; tubercle conic, minute, 

 depressed but rather acute, constricted at the base. 



Moist grounds. Lake Chelan, Washington; Nebraska to 

 Texas, Iowa, and Florida. Europe and Asia. Type locality: 

 India. Recorded by Piper as E. capitata. 



3, Eleocharis ovata ( Roth ) R. & S. 

 Ovoid Spike-rush. Fig. 626. 



Scirpus 0','atus Roth, Catal. Bot. 1: S. 1797. 

 Eleocharis ovata R. & S. Syst. 2: 152. 1817. 



Annual, with fibrous roots; culms tufted, slender 

 to filiform, nearly terete, mostly erect, 0.5-4 dm. long. 

 Upper sheath 1-toothed; spikelet ovoid to oblong, 

 many-flowered, obtuse, 4-10 mm. long : scales oblong- 

 orbicular, obtuse, brown; bristles 6-8, sometimes 

 fewer, or wanting, usually longer than the achene ; 

 stamens 2 or 3 ; style mostly 2-cleft : achene pale 

 brown, smooth, shining, lenticular, obovate-oblong, 

 about 1 mm. long; tubercle deltoid, acute, its base 

 narrower than the top of the achene. 



Oregon (£. Hall), the specimen formerly referred by 

 Watson to E. olivacca Torr. and by me to E. capitata. Michi- 

 gan to New Brunswick and Connecticut. Europe. Type lo- 

 cality: Germany. 



