292 Juncaceae Juncus 



Capsule half to two thirds as long as the calyx; sepals rigid, subulate, 

 much longer than the petals; heads spherical; culms from thick, 



elongate rhizomes 16. J. brachycarpus. 



Capsule nearly equaling or exceeding the calyx; sepals and petals sub- 

 equal; heads usually hemispherical; culms cespitose, not rhizomatous. 

 Heads 1-50; flowers several to many in a head; perianth 3-3.5 mm long; 



capsule acute or mucronate 17. J. acuminatus. 



Heads 200-500; flowers few in a head; perianth 2-2.5 mm long; capsule 

 shorter, broader, much less rigid, blunt; nodes fewer, less con- 

 spicuous, of the same color as the culm 18. J. nodatus. 



Stamens 6. 



Flowers solitary or in pairs, often reduced to fascicles of small leaves 



19. J. pelocarpus. 



Flowers more numerous, in heads. 



Heads spherical, few, large (7-15 mm wide); capsule subulate; sepals 

 subulate; involucral bract usually exceeding the inflorescence. 

 Plant low, 1-4 dm high; leaf blades erect or ascending; flowers 3-4 mm 



long; petals usually equaling or exceeding the sepals 



20. J. nodosus. 



Plant taller, 4-10 dm high; leaf blades divaricate; flowers 4-5 mm long; 



petals usually shorter than the sepals 21. J. Torreyi. 



Heads hemispherical, more numerous, smaller (6 mm wide or less); capsule 

 ovoid or ellipsoid; sepals blunt or acute; involucral bract shorter than 

 the inflorescence. 

 Sepals and petals acute or acuminate; capsule strongly acute; branches 

 of the inflorescence usually widely spreading. .. .22. /. articulatus. 

 Sepals and petals mostly obtuse, often scarious at the apex; capsule 

 from obtuse to broadly acute or apiculate; branches of the inflores- 

 cence rarely widely spreading. 

 Heads loosely few-flowered, usually with one or more flowers ele- 

 vated on slightly prolonged peduncles; branches of the inflores- 

 cence erect or strongly ascending. . .23. J. alpinus var. rariflorus. 

 Heads compactly and regularly several- to many-flowered; branches 



of the inflorescence spreading-ascending 



23a. J. alpinus var. fuscescens. 



1. Juncus effusus L. var. solutus Fern. & Wieg. (Rhodora 12: 

 90. 1910.) Map 599. Very common in ditches, sloughs, low fields, wet 

 open woods, marshes, bogs and on borders of lakes. Often locally abundant. 



N. S. to Wis., southw. to Fla. and Tex. 



la. Juncus effusus var. Pylaei (Laharpe) Fern. & Wieg. (Rhodora 

 12: 92. 1910.) Map 599a. Infrequent in the northern part of the lake area, 

 except on the dunes where it is frequent. A northern variety growing in 

 habitats similar to the preceding variety and reaching the southern limit 

 of its range in northern Indiana. 



Newf. to Wis., southw. to W. Va. and Ind. 



2. Juncus balticus Willd. var. littoralis Engelm. Map 600. Infrequent 

 in the dune area where it is found on the sandy borders of sloughs and 

 lakes, in interdunal swales and marshes, and in moist depressions of the 

 sandy beach of Lake Michigan. The elongate rootstocks of this rush, and 

 of the following form, usually radiate in many directions from a common 

 center and often attain a length of a yard or even several yards. 



Newf. to N. Y., Pa., and the Great Lakes. 



