THE CYPERACEAE OF COSTA RICA. 



By C. B. Ci m:ki . 



SYNOPTICAL KEY TO THE GENERA. 



Subfamily I. Scirposchoeneae. Fertile flowers all with perfecl stamens. 

 Empty glumes at the base of the spikelets, 2 or none; fertile glumes, 2-ranked; hypog- 

 ynous bristles none; inflorescence subumbellate or capitate, never paniculate. 

 Cypereae.) 

 Style 2-branched; nut compressed laterally. 



Rachilla above the two empty glumes deciduous.. 1. Kyllinga p. ill 

 RachUla above the two empty glumes persistent.. 2. Pycreus p. 145 

 ■ Style 3-branched. 



Rachilla persistenl 3. Cyperus (p. 447 



Rachilla deciduous 4. Mariscus p. 451 



Rachilla breaking into as many joints as then- an' 



nuts •">. Torulinium (p. 454 



Empty glumes at base 2 or none; fertile glumes in 3 to 

 several ranks; inflorescence not panicled (excepl in 

 Fuirena >. Scirpeae. 

 Style base bulbous, separable from the apex of the 

 nut. Bristles usually < )l>\i< >us: culm leafless; -pike- 

 lei terminal • '>. Eh ocharis p. 454) 



Bristles none; plants commonly leafy. 



Style persistent, or else deciduous along with 



the style base 7. Fimbristylis I p. 457 



Style (leei<luoii>. its discolored base remain- 

 ing <>n the nut 8. Bulbosti/lis p. 459) 



Style base not l>ull><>us. passing gradually from the 

 nut into the style proper. 



Plants glabrous; inflorescence capitate 9. Scirpus (p. 4<io 



Plants pilose; inflorescence paniculate JO. Fuirena p. 160 



Empty glumes at base of spikelets :'» to several; styles bifid. 



I RyNCHOSPOREA i: 



Spikelet cylindric; rachilla breaking into as many 



joints as there are nuts 11. Dulichium p. 160 



Rachilla short, persistent. 



Hristles none; Btyle branches 2, long; head of 



spikelets, one only 12. Diehromena (p. 461 



Style branches 2, very short in those Bpecies hav- 

 ing monocephalous inflorescence, long in those 



with inflorescence not monocephalous 13. Rynchospora p 162 



Subfamily II. Sclericariceae. Mowers all unisexual, 

 the fertile onea axillary. 



143 



