CLARKE THE CYPEB \< EA1 I »l I < »s'i \ RICA. 445 



byprolepis denudata Steud. Syn. PI. Glum. 2: 130. i- 

 Distribution: Tropical ^.mericaand Africa 



Costa Rican collections: Puerto Limon, Pitlier 1215; Boca Banana, Tondm 

 9122. 



•1. Kyllinga pumila Michx. II. 1: 28. L803. 



Kylhnga caespitosa Neea in Mart. Fl. Bras. 2 : L2. L842, excluding Kunth Bynonym 

 and variel y />'. 



Distribi pion: Common throughout tropical and temperate America; Erequenl in 

 Africa. 



Costa Rican collections: Hoffmann 231, 137, 169; Polahowsky I. L60, M)9 

 Carlos. Tonduz 2583; Boruca, Tondm 1:793; Talamanca, Tonduz&747\ Rio Tula, alti- 

 tude 600 meters, Tondm 8180; Turrialba, altitude 570 meters, Tondm 8264; Rio 

 Aqua Caliente, altitude I. :'><><> meters, /'////,/■ 2403. 



5. Kyllinga odorata Vahl, Kinim. 2: 382. L806. 



Kyllinga elongata II. B. K. Nov. Gen. & Sp. 1: 211. L815. 



Distribution: Very common in North ami South America from Louisiana to 

 Uruguay. 



Costa Rican collections: Hoffmann 702; Rio San Juan, Pittier 2580; Greytown; 

 Alajuelita, altitude L,000 meters, Tondm 8849; San Jose\ altitude L,100 meters, 

 Tondm 434. 



2. PYCREUS Beauv. 



Spikelets 5 to many-flowered; rachilla persistent; two low -.-i glumes empty, per- 

 sistent; I "i- mi. re nexl succeeding 2-ranked, bisexual, perfecting outs, caducous in 

 fruit from the lowest upward: a few <.f the uppermost sterile or vacant, arranged in 

 about 3 spirals; hypogynous bristles none; stamens 1 to:;, anterior; style branches 

 2, on a plane passing through the rachilla; nut laterally compressed. — Plants glabrous. 

 Stems leafy near the base, otherwise naked. Spikelets arranged in spikes, often dense, 

 hardly digitate. 



Species 63 distributed to the warmer regions of both hemispheres, a few extending 

 to within the Temperate Zone 



KEY TO THE SPECIES. 



Superficial cells of the nut . at least in many, longitudinally oblong; nut transversely 

 and delicately undulateJineate. i Zonatae.) 



Annual, tufted, often simply umbellate 1. P. flavesct ns. 



Superficial cells of the nut subquad rate; nut minutely reticu- 

 late, punctulate, or granular. (Rettculatae.) 

 Spikelets b1 raw-colored or brownish-yellow. 



Umbels crowded into a single head 2. P. propinquus. 



Spikes subglobose, commonly umbellate 3. P. helmcs. 



Spikelets chestnut-brown or variegated with chestnut. 



Annual, spikelets subinflated, arranged in loose spikes. I. /'. lagunetto. 

 Stems decumbenl at base, often creeping; spikelets 

 rigid, forming dense spikes. 



Spikelets 3 mm. wide 5. P. nu lanostachyus. 



Spikelets 2 mm. wide 6. /'. - legantulus. 



1. Pycreus flavescens iT.. i Beauv.; Reichenb. PI. Excurs. 1: 72. 1830 L832. 

 Cyperus fiavescens L. Sp. PI. 1: 46. L753. 

 Cypt nis/asrirnlalus Ell. Bot. S. C. & Ga. 1: 63. L816. 

 Cyperus elliotianus Schult. in Roem. & Schult. Syst. Mam. 2: LOO. L824. 

 Pycreu8 elliottianus Nees, l.innaea 9: 283. L834. 

 Cyperus durandii Boeck. Allgem. Bot. Zeitschr. 1: l s ~>. L895. 



