bottom submerged, at each node with a cluster of basal leaves and fibrous roots 

 and eventually at each emergent (not submerged) terrestrial node with an ascend- 

 ing floriferous culm (5-) 10-30 cm. long, this with only 1 or 2 nodes and these 

 lower nodes bearing clusters of leaves; blades weak, ascending, more or less flat, 

 5-10 cm. long, 2-3 mm. broad, not septate, tapering to a fine point; panicle 

 terminal, 7-13 cm. long, simple or few-branched, of 2 to ten 3- to 12-flowered 

 rotate-turbinate glomerules which are terminal on the branches or else appearing 

 sessile at the nodes; individual flowers 5-10 mm. long, subtended by only 1 bractlet 

 at the base of the pedicel; sepals and petals rigid, lance-subulate, setaceous-tipped, 

 the petals much longer than the sepals; stamens 3; capsule linear or at least very 

 narrow, apically obtuse, about as long as the sepals. 



Margins of fresh water ponds and sandy loam soil, in swamps and bogs, in 

 Okla. (LeFlore Co.) and e. Tex., infrequent to rare, summer; Coastal States, Del. 

 to Tex. and inland to Tenn., Ark. and Okla. 



18. Juncus filipendulus Buckl. Fig. 318. 



Perennial, tufted or from masses of slightly swollen bulbil-like bases; culms 

 15-30 cm. long, compressed, 0.5-1 mm. broad (in largest transverse dimension), 

 leafy, erect or some of them basally shortly decumbent; sheaths shorter than their 

 internodes; blades flat, soft, membranous, 2-10 cm. long, 1-2.5 mm. broad, mostly 

 ascending; panicle terminal, few-branched, of 2 to 5 (to rarely 10) headlike glom- 

 erules or reduced to a single glomerule; glomerules hemispherical, 7-10 mm. 

 across, stramineous, of 6 to 15 essentially sessile flowers, each subtended by 1 

 (rarely 2) bracteoles; perianth 4-5 mm. long, whitish to stramineous; stamens 3; 

 capsule obovoid, much shorter than the perianth. 



Moist calcareous soil or shallow water along streams, in Okla. (Arbuckle Mts., 

 Waterfall), infrequent in Edwards Plateau, rare in n.-cen. Tex. and e. part of 

 Plains Country, spring-summer. 



19. Juncus marginatus Rostk. Fig. 319. 



Perennial from enlarged, bulblike bases (these often connected by short rhi- 

 zomes); aerial culms 1 to 3 from each bulb, 15-100 cm. long, compressed, 1.5-3 

 mm. broad (in largest transverse dimension), leafy, erect or some culms basally 

 shortly decumbent; sheaths much shorter than their internodes, with narrow hya- 

 line margins near the corners; blades flat, soft, membranous, 3-15 cm. long, 2-5 

 mm. broad, mostly erect or distally decurved-arcuate, abruptly acute; panicles 

 terminal, much-branched and compound, the branches ascending, each of the 10 

 to 80 ultimate branches bearing a glomerule of 2 to 12 essentially sessile flowers; 

 each glomerule subtended by as many bracteoles as it has flowers or a few more; 

 perianth 2.5-3.5 mm. long, brownish; stamens 3; capsule rotundly obovoid, about 

 equaling the perianth, brown. Incl. var. paucicapitatus Engelm., J. aristitlatus 

 Michx., /. hi floras Ell. 



In marshes, wet meadows, seepage areas, on edge of lakes, ponds and streams, 

 in most of Okla and Tex., common in e. half, infrequent to rare in w. part, and 

 Ariz. (Santa Cruz, Graham and Pima cos.), spring-summer; e. half of temp. N.A., 

 rare w. to Ariz. 



Var. setosus (Small) Cov. with glossy capsules and aristate inner perianth 

 segments occurs in Arizona. 



20. Juncus longistylis Torr. 



Perennial plants from short rootstocks; stems 20-50 cm. tall, loosely cespitose; 

 basal leaves flat, with well-developed auricles; stem leaves 1-4 mm. wide, flat or 

 somewhat involute, the flat edges inserted next to the sheaths with scarious 



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