540 juncacejE. (rush family.) 



13. J. tenuis, Willd. Stem wiry (9' -18' high); leaves flat or channelled; 

 panicle shorter than the involacral leaves, loose, or rarely crowded ; flowers giocn 

 (2'' or more long) ; sepals lanceolate, very acute, spreading in fruit, longer tluin 

 the ovoid retuse scarcely pointed green pod ; anthers nearly equal to the fila- 

 ment ; style very short ; seeds small (about i" long), white-pointed at both ends, 

 delicately ribbed and cross-lined. — Low grounds, fields, and roadsides. (Eu.) 

 — Var. SECTJNDUS is a smaller plant, with smaller one-sided flowers on the 

 forked branches of the panicle. New England to Pennsylvania. 



14. J. diehdtomus. Ell. Stems rigid (lJ°-2° high) from a tumid 

 base ; leaves filiform, nearly terete, slightly grooved on the inner side ; panicle 

 loose, often witli 1 -sided forked branches, mostly longer than the involucral leaf; 

 flowers greenish (2" or more long) ; sepals lanceolate, sharp-pointed, spreading 

 in fruit, as long as the globular beaked light mahogany-colored pod ; anthers 

 nearly as long as filaments ; sty le short ; seeds small ( ^" - 4" long) , white-pointed 

 at both ends, coarsely cross-lined. — Low sandy grounds. New Jersey (0. F. 

 Parker], Delaware (Prof. Leidy, Mr. Commons), and southward. 



15. J. Gre6nii, Oakes & Tuckerm. Stems rigid (l°-2° high); leaves 

 nearly terete, very deeply channelled (almost involute) on the inner side; pan- 

 icle usually much shorter than the principal erect involucral leaf, dense ; the 

 numerous crowded flowers often one-sided (1 J" long) ; sepals lanceolate, acute, 

 light greenish-brown, appressed, shorter than the ovoid-oblong obtuse greenish- 

 brown pod; anthers as long as filaments; style very short; seeds ovoid, tail- 

 pointed (i" - f ' long), ribbed and delicately cross-lined. — Sandy coast of New 

 England, and on the Great Lakes near Detroit (Holzer, J. M. Bigelow). 



16. J. Viseyi, Engclm. S tems rigid (I°-2|° high) ; leaves nearly terete, 

 very slightly channelled on the inner side ; panicle longer than the involucral 

 leaf, loose ; flowers few, often one-sided, greenish or light brown (2" or more 

 long) ; sepals lanceolate, acute, appressed, shorter than the oblong and retuse 

 green-brown pod ; anthers as long as the filaments ; style very short ; seeds 

 slender, conspicuously tailed at both ends (J"-i" long), closely ribbed. — 

 Michigan, with the last (near Detroit, HoUer, Bigelow) to N. Illinois ( Vasey), 

 and westward. June. 



§3. Knottt-leaved Junci ; stems leafy, simple or branching: leaves terete 

 or sometimes laterally compressed, knotted by internal cross-partitions : panicle 

 terminal, with flowers chiefly in heads. 



* Seeds barely pointed, without tails. 

 H- Heads composed of 2 or sornetimes only single G-androus fowers. 



17. J. peloc^rpus, E. Meyer, Stems slender and erect from a slender 

 running rootstock (6' - 18' high), bearing few thread-like slightly knotted leaves, 

 branching above into a compound spreading panicle, bearing in the forks and 

 along one side of the branches single flowers or 2-flowered heads ; often with the 

 flowers or in place of them are tufts of leaves ; flowers small (l'-l,i' long), green- 

 ish with red ; sepals oblong, obtuse, the 3 inner ones longer, but shorter than the 

 oblong taper-beaked 1 -celled pod ; anthers much longer than the filaments ; style 

 slender; seeds (i" long) obovate, short-pointed, delicately ribbed-rcticulatcd. 

 (J. vivi'parus, Conrad. J. Conradi, Tuckerm. ) — Sandy, wet or swampy places, 



