370 CYPERACE.E. (SEDGE FAMILY.) 



ing cylindrical : stamens 2 or 3 : akene very minutely striate and obscurely reticu- 

 lated. — Colorado to Indian Territory and Texas ; also along the Atlantic 

 coast. 



7. KOBRESIA, Willd. 



Lowest glume enclosing an ovary with a long trifid style ; the next one, or 

 rarely the next two, enclosing 3 stamens; often a rudimentary glume or awn 

 terminating the rhachis ; occasionally but one glume to a spikelet. — Peren 

 nial herbs with filiform leaves, radical or sheathing the stems at base. 



1. K. scirpina, Willd. Stems cespitose, 5 to 12 inches high, striate- 

 angled : leaves shorter than the stem : spikelets few, small, and brown, in a 

 somewhat clavate spike one inch long. — Elyna spicata, Schrad. South Park, 

 Colorado (Hall $* Harbour). 



8. CAR EX, L. Sedge. (By L. H. Bailey, Jr.) 



Flowers in spikes, imperfect, the staminate and pistillate in different parts 

 of the same spike (spike androgynous), or in separate spikes on the same culm 

 (plant monoecious), or rarely on entirely distinct plants (plants dioecious). 

 Staminate flower composed of 3 stamens borne beneath a bract or scale. 

 Pistillate flower composed of a single pistil bearing 2 or 3 exserted styles, 

 forming in fruit a lenticular or triangular acheuium which is enclosed in a 

 more or less inflated sac (perigynium) borne in the axil of a scale. — Perennial 

 grass-like herbs with 3-ranked leaves, mostly triangular culms, and spikes in the 

 axils or exserted from the sheaths of leaf-like or scale-like bracts. Theoreti- 

 cally each flower is entirely destitute of floral envelopes, and borne on a branch 

 which springs from the axil of a scarious bract (the scale of the following 

 descriptions), the enclosing perigynium of the fertile flowers answering to one 

 (or two) connate bractlet. The term fruit as applied to the perigynium and 

 its contents is a misnomer. In the subgenus Vignea of the present elabora- 

 tion the spikelets or spiculae of authors are called spikes, which they truly are, 

 and they are conglomerated into heads. The genus is an exceedingly critical 

 one and its study should not be attempted with unripe or imperfect specimens. 



Artificial Key. 



I. Spike one, terminal, strictly simple, staminate at the top, or in dioecious plants (5 & 46) 



all staminate of all pistillate. 

 Stigmas three. 

 Perigynium spindle-shaped or lanceolate, 



Green 1 



Dark brown or purple 2, 3 



Perigynium short, mostly ovate or elliptic, 

 Perfectly smooth. 

 Perigynia 1 to 3, conspicuously spreading, or remote from the staminate portion, 



Obovate, obtuse .10 



Elliptic, sharply beaked 16 



Perigynia several, continuous with the staminate portion. 



Scales leaf-like 11 



Scales short, ciliate 4€ 



Scales short, entire, 



