100 CONTRIBUTIONS FROM THE NATIONAL, HERBARIUM. 



3. Scleria pauciflora Muhl. 



Sandy woods; frequent above the fall line. May-July. Southern states, north to 

 N.J. 

 3a. Scleria pauciflora caroliniana (Willd.) Wood. 



Sandy field, east of Bennings. July. Eastern U. S., rare and local. 



4. Scleria reticularis Michx. 



Wet sandy open ground and magnolia swamps; Chevy Chase and eastward, mostly 

 below the fall line; frequent; associated with sphagnum and Panicum lucidum. Aug.- 

 Sept. Atlantic Coastal Plain and at the head of Lake Michigan. 



13. CAREX L. Sedge. 



Complete specimens with mature fruit are necessary for the identification of species 

 in this genus. Diagnostic characters are found mainly in the shape, size, and texture 

 of the perigj-nium (the sac-like body inclosing the achene) ; in the shape of the achene 

 and the number of stigmas; in the relative position of the pistillate and staminate 

 flowers (the latter usually represented in mature plants only by empty scales or, occa- 

 sionally, by filaments); in the presence or absence of sheaths on the lower bracts of 

 the culm; and in the appearance of the rootstocks. 



Achenes lenticular; stigmas 2 ' Subgenus I. VIGNEA. 



Aclienes trigonous: stigmas 3 Subgenus n. ETJCABEX. 



Subgenus I. VIGNEA (Beauv.) Nees. 



Staminate and pistillate flowers on the same spike (C. bromoides sometimes dioe- 

 cious); lateral spikes sessile. 



Staminate flowers above the pistillate. 



Spikes usually 10 or fewer, green when mature (C viuricata has purplish-tinged 



scales) 1. Muhlenbergianae. 



Spikes usually more numerous, yellowish or tawny when mature. 



Beak of perigynium equaling or shorter than the body, the base not spongy. 



Perigynia papery, green to dull brown 2. Multiflorae. 



Perigynia hard, shiny brown 3. Paniculatae. 



Beak of perigynium much exceeding the body, the base spongy. 



4. Stenorhynchae. 

 Staminate flowers below, or occasionally intermixed with, the pistillate. 



Perigynia not wing-margined, at most thin on the margin and then spongy at base. 

 Base of perigynium not spongy, the margin not thin. 



Spikes short, obovoid; beak of perigynium very short, obscure. 



5. Canescentes. 

 Spikes long, lance-cylindric ; beak of perigynium fully half as long as the body. 



6. Deweyanae. 



Base of perigynium spongy, the margins thin 7. Elongatae. 



Perigynia wing-margined, not spongy at base. Spikes ovoid 8. Ovales. 



Subgenus n. EUCAREX Coss. & Germ. 



One or more spikes strictly pistillate (except in C. leptalea and C typhina, and 

 sometimes in C. squarrosa), the terminal commonly staminate, the lateral often 

 pedunculate. 



Achenes lenticular; stigmas 2 9. Acutae. 



^ Six of our species of Eucarex have lenticular achenes and two stigmas. They are 

 readily distinguished from the Vigneae by their having one or more spikes strictly 

 staminate or nearly so. See key to Eucarex. 



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