JUNCACEAE 261 



32. Juncus robustus (Engelm.) Coville. Plants 6-10 dm. high. Rootstock short, 

 inconspicuous : stems few in a tuft, nearly terete, 2-3 mm. thick below, 1-2-leaved : 

 leaf-blades erect, terete, conspicuously septate, 20-60 cm. long, 2-3.5 mm. thick, usually 

 reaching the inflorescence : inflorescence 10-25 cm. high, with moderately spreading 

 branches and many ( 300-500) heads, its largest bract with the blade obsolete or sometimes 

 as long as the inflorescence : heads 2-10-flowered : perianth 2-3 cm. long : sepals and petals 

 nearly equal, lanceolate-subulate : stamens - as long as the perianth : capsule 1-1 J 

 times as long as the perianth, light brown or almost stramineous at maturity, narrowly to 

 broadly oblong, obtuse but short apiculate, 3-angled when dry, 1-celled, the valves sepa- 

 rate and involute after dehiscence : seeds as in J. acuminatus. 



In low grounds, Illinois to Kansas, Louisiana and Texas. Summer. 



33. Juncus Elliottii Chapm. Plants 2-8 dm. high. Stems tufted, from branched 

 congested rootstocks, 3-leaved, nearly terete : lower leaf-blades commonly 8-15 cm. long, 

 or rarely reaching 25 cm. high, or occasionally somewhat larger, with moderately spreading 

 branches, and 5 or sometimes 50 heads, the blade of the lowest involucral bract usually ob- 

 solete, or rarely 4 cm. long : heads 2-5-flowered : perianth 2-2.5 mm. long : sepals and 

 petals equal, lanceolate and acute : stamens J-f as long as the perianth ; anthers shorter 

 than the filaments : capsule oblong to narrowly oblong, chestnut-brown above and shin- 

 ing, broadly acute, equalling the perianth, 1-celled, the valves spreading and often invo- 

 lute when mature : seeds lanceolate-oblong, 0.35-0.45 in length, reticulated in about 

 12-14 rows, the areolae linear-oblong, and smooth, or marked with a single longitudinal 

 line. 



In bogs or ditches, North Carolina to Florida and Texas. A large form, J. Elliottii polydnthemus C. 

 Mohr, has stems 6-8 dm. tall, flat long-acuminate leaves 25-35 cm. long, and panicles with very num- 

 erous (100-200) 4-6-flowered heads ; it occurs in southern Alabama. Summer and fall. 



34. Juncus acuminatus Michx. Plants 2-8 dm. high. Rootstock short and in- 

 conspicuous : stems few or several in a tuft, terete or slightly compressed, 1-3-leaved : 

 blades of the lower leaves 10-18 cm. long, 1-2 mm. thick, the upper shorter : inflorescence 

 c 'nimonly 5-15 cm. high, and with 5-50 heads, rarely larger, or reduced to a single head, 

 its branches usually spreading or sometimes strict : heads 3-20-flowered, commonly 5-12- 

 flowered : perianth 2.5-3.5 mm. long : sepals and petals lanceolate-subulate, nearly 

 equal : stamens about J as long as the perianth : capsules ovoid-lanceolate, broadly acute, 

 mucronate, 1-celled, equalling the perianth, light brown, the valves separating through 

 the apex in dehiscence : seeds narrowly to broadly oblong, 0.4-0.55 mm. in length, acute 

 at both ends, reticulated in about 16-20 longitudinal rows, the areolae transversely plu- 

 rilineolate. 



In low grounds, Maine to Ontario, Minnesota, Georgia, Texas and Mexico. Also on our north- 

 western coast. Spring. 



35. Juncus d6bilis A. Gray. Plants 2-4 dm. high or sometimes with weak procum- 

 bent stems, often densely tufted. Leaves with blades usually less than J the height of the 

 plant, more or less involute in age or in drying : panicle with ascending or diffuse 

 branches : heads mostly 2-6-flowered : perianth 2-2.5 mm. long : sepals and petals nar- 

 rowly lanceolate, the petals broader at the base and less concave : stamens much over as 

 long as the perianth : capsules linear-lanceolate in outline, about J exceeding the 

 perianth. 



In wet places and sandy shores, New Jersey to Missouri, Florida, Mississippi and Arkansas. 

 Spring and summer. 



2. JUNCOIDES Adans. 



Perennial caulescent herbs, with glabrous or sparingly webby -pubescent foliage. 

 Leaves with closed sheaths and grass-like blades. Inflorescence various, often congested. 

 Flowers always subtended by bractlets, these usually lacerate or denticulate. Stamens 6 

 (incur species). Ovary 1-celled. Ovules 3, basal. Capsule sessile, 1-celled. Seeds 3, 

 reticulated, sometimes carunculate but not distinctly tailed. [Luzula DC.] WOOD-RUSH. 



Peduncles terminated by 1 or rarely 2 flowers : capsule of an ovoid type. 1. J. pilosum. 



Peduncles terminated by compact spikes : capsule of an obovoid type. 



Sepals and petals 3-4 mm. long : capsule much surpassed by the perianth. 2. J. echinalum. 



Sepals and petals 2-2.5 mm. long : capsule surpassing the perianth or about equal- 

 ling it in length. 3. /. bulbosum. 



1. Juncoides pilosum (L.) Kuntze. Stems 1-3 dm. tall, 2-4-leaved : leaf -blades 

 flat, 3-8 mm. wide, webby, especially when young, blunt and almost gland-like at the 

 tip : inflorescence umbel-like, subtended by a bract 10-25 mm. long : peduncles filiform, 

 equal or nearly so, 1-flowered or rarely 2-flowered : perianth 2.5-3 mm. long : sepals and 

 petals triangular-ovate, brown except the hyaline margins, about twice as long as the 



