against the internode and abaxia! one at the keel of the lower scale, obovate or 

 oblong-obovate, 1-1.2 mm. long (plus an apicule 0.05-0.1 mm. long), (0.6-) 

 0.7-0.8 mm. broad, ripening to a rich-brown. Kyllinga brevifolia Rottb. 



Common weeds in moist or wettish loam, s.e. Tex., less common in e. Tex., 

 rare in Edwards Plateau and Brownsville region, and Okla. {Waterfall), Apr-Nov.; 

 widespread in warn regions. 



3. Cypenis tenuifolius (Steud.) Dandy. Fig. 215, 



Densely tufted fragrant annual (or short-lived perennial ?) with density of 

 about 4 to 20 culms per square cm.; culms 1-21 cm. long, 0.5-0.7 mm. thick 

 throughout; leaves with sheaths 8-45 mm. long and membranous; flaccid blades 

 2-11 cm. long, 1-1.8 mm. broad, often more than two thirds as long as the culms; 

 inflorescence a single roundish 3-lobed compound headlike mass 3-8 mm. long and 

 5-6 mm. broad in the upper obtuse lobe, with 40 to 170 spikelets altogether; 

 bracts 3 (or 4), ultimately spreading or slightly reflexed, flaccid, 2-10 cm. long, 

 1-2 mm. broad, at the very base with broad translucent membranous corners; 

 spikelets each deciduous as a unit, 2-2.5 mm. long, 0.7-0.8 mm. broad, about 0.3 

 mm. thick, sordid-whitish or very pale-brownish, with 2 scales, the lower one 

 enclosing a fertile floret, the upper empty, the single short internode with very 

 broad hyaline wings clasping the achene and continuous with the lower part of 

 the higher scale; scales persistent (the lower one 1.7-2.4 mm. long) with green 

 keels and translucent sides, each side with a couple of inconspicuous well- 

 distributed longitudinal nerves; stamens uniformly 2 at the abaxial angle of the 

 achene; stigmas 2; achene lenticular, with the adaxial angle against the internode, 

 the abaxial one at the keel of the lower scale, elliptic, 0.9-1.1 mm. long (plus an 

 apicule 0.1 mm. long), 0.5-0.6 mm. broad, ripening to a very dark-brown. 

 Kyllinga pumila Michx., Cyperus densicaespitosus Mattf. & KUkenth. 



Infrequent in moist loam, in marshes along streams, edge of ponds and other 

 wet areas, e. Tex. (Bowie, Cass, Hardin and Polk cos.), rare in n.-cen. Tex. 

 (Grayson Co.), and Okla. (McCurtain Co.), Sept.-Nov.; widespread in warmer 

 moister parts of Am.; also Afr. and Madag. 



The name is incorrectly said by some writers to be illegitimate. 



4. Cyperus sesquiflorus (Torr.) Mattf. & Kiikenth. 



Annual (?) or usually perennial mat-formers, emitting a strong citronellalike 

 odor when bruised, with a culm density of 1 to 4 flowering culms per square cm. 

 in the mat; culms 5-30 cm. long, basally 0.8-1.8 mm. thick, apically 0.5-1 mm. 

 thick; leaves essentially basal, with sheaths 1-2 (-3) cm. long and firm-mem- 

 branous, ascending blades 3-12 cm. long and 2-3.5 (-5) mm. broad, mostly 

 much shorter than the scapelike culms; inflorescence a single prolate few-lobed 

 compound congested headlike mass 7-14 mm. long and 6-8 mm. broad in the 

 upper cylindrical lobe, with 50 to 200 spikelets altogether; bracts 3 (or 4), ulti- 

 mately slightly to strongly reflexed, firm-membranous, 2-8 cm. long, 1-3 mm. 

 broad, at the very base discolored whitish-green but not hyaline at corners; spike- 

 lets each deciduous as a unit, 2.3-3 mm. long, 1.2-1.3 mm. broad, about 0.4 min. 

 thick, with 2 scales, buffy-white to white laterally, the lower scale enclosing a 

 fertile floret, the upper one empty, the single short internode with very broad 

 hyaline wings clasping the achene and continuous with the lower part of the 

 higher scale; scales persistent (the lower one 2.2-2.9 mm. long) with green keels 

 and buffy-white to white sides, each side with a couple of inconspicuous well- 

 distributed longitudinal nerves; stamens uniformly 2 at the abaxial angle of the 

 achene; stigmas 2; achene lenticular with the adaxial angle against the internode, 

 the abaxial one at the keel of the lower scale, obovate, 1-1.4 mm. long, plus an 

 apicule 0.05-0.15 mm. long, 0.75-0.9 mm. broad, ripening to jet-black. Kyllinga 



423 



