118 CONTRIBUTION'S FROM THE NATIONAL HERBARIUM. 



Sepals very acute, pale green or straw-colored, equaling or exceeding the pale 

 capsule; leaves all basal or essentially so. 

 Leaves sub terete, merely channeled above; basal sheaths usually purplish- 

 tinged; flowers 3.5-5 mm. long, in 1-sided racemes; leaf sheaths with 

 short cartilaginous auricles (the narrow borders at the apex of the 



sheaths) 7. J, dichotomus. 



Leaves flattened, but sometimes inrolled in drying so as to appear involute; 

 basal sheaths brownish or straw-colored. 

 Auricles of the leaf sheaths cartilaginous, yellowish when dry. 



4. J. dudleyi. 



Auricles of the leaf sheaths membranaceous or sub membranaceous, 



whitish or brownish. 



Auricles thin, scarious, whitish, 1-3 mm. long; flowers 3.5-5 mm. 



long, loosely scattered or clustered; inflorescence shorter than its 



lowest bract 6. J. tenuis. 



Auricles firmer, brownish, less than 1 mm. long; flowers 2.5-3.5 mm. 

 long, arranged in 1-sided racemes; inflorescence usually lunger than 

 its lowest bract 6. J. secundus. 



1. Juncus effusus L. Common rush. 

 Meadows and wet places; rather common. June-Aug. N. Amer. and Eur. 



The form occurring with us is J. effusus solutus Fern. & Wieg. 



2. Juncus bufonius L. Toad rush. 

 Dried-up pools and wet places; common. May-July. Cosmopolitan. 



3. Juncus gerardi Loisel. Black grass. 

 Known only from streets of Alexandria, where first collected by Vasey. July. Nearly 



cosmopolitan. 



Abundant, outside our limits, in the salt marshes of Chesapeake Bay. 



4. Juncus dudleyi Wiegand. 



Sandy bogs and damp sands; scarce; flats of the Potomac, southwest of Washington 

 Monument (Coville); High Island and First Lock (Ward). May-June. Greater part of 

 N. Amer. 



5. Juncus tenuis Willd. Path rush. 

 Abundant throughout in sandy soil; a characteristic plant along paths. June- 

 Aug. N. Amer.; introd. and spreading in the Old World. 



6. Juncus secundus Beauv. 



Fairly common in sandy abandoned fields. June. Eastern N. Amer. (J. tenuis 

 secundus Engelm.) 



7. Juncus dichotomus Ell, 



Low sandy ground and meadows; frequent, especially toward salt water. June- 

 Sept. Eastern N. Amer.; trop. Amer. 



8. Juncus marginatus Itostk. 



Meadows and wet grounds; abundant. June-Sept. Eastern N.'Amer. (Includes 

 J. marginatus vulgaris of Ward's Flora.) 



9. Juncus aristulatus Michx. 



Frequent in grassy places. June-July. Eastern N. Amer., south to Mex. (/. 

 marginatus biflorus of Ward's Flora; J. marginatus aristulatus Coville.) 



10. Juncus torreyi Coville. 



Damp sandy ground; scarce; vicinity of Washington (Ward); reservoir, Howard 

 University, and Jackson City (Steele). July-Aug. Eastern N. Amer. (J. nodosus 

 megacephalus Engelm.) 



11. Juncus scirpoides Lam. 



Wet sandy soil; common. July-Aug. Eastern N. Amer. (/. scirpoides macroste- 

 mon Engelm.) 



