JUNCACEAE (RUSH FAMILY) 



269 



Stamens included in fruit. 

 Petals ovate or oblong, blunt ...... 43. J. marginatus. 



Petals lance-attenuate, aristate . . . (43) J. marginatux, v. setosus. 

 Stamens persistent and exserted in fruit . . . . 44. J. aristulatus. 



m. Capsules 6-9 mm. long, much exceeding the calyx ; flowers 



few, in 1-4 terminal glomerules . . . . 41. /. stygius, v. americanus. 



c. Leaves hollow, nodulose, i.e. with septa at regular intervals n. 

 n. Seeds with definite caudate tips o. 



o. Leaves papillose-scabrous ; stamens 6 ; seeds 2-3 mm. long . 21. J. asper. 

 o. Leaves smooth ; stamens 3 ; seeds shorter p. 

 p. Flowers with the mature fruit about 2.5 (rarely 3.5) mm. long ; 

 sepals obtuse; seed ellipsoid, barely 1 mm. long, with 

 very short tails .... .... 



p. Flowers with mature fruit about 4 mm. long : petals attenu- 



ate, acute ; seed spindle-shaped, with conspicuous tails. 

 Inflorescence (when well developed) ovoid or broader, one 

 third longer than broad ; the glomerules many-flowered ; 

 capsule equaling or slightly exceeding the calyx. 

 Capsule abruptly short-pointed ; seed 1-1.8 mm. long 

 Capsule gradually tapering to tip ; seed scarcely 1 mm. 



long ....... (24) J. canadensis, v. subcaudatus. 



Inflorescence elongate, strict, and narrow, 3-6 times longer 

 than broad ; capsule much exceeding the calyx, gradu- 

 ally tapering ; seed about 1 mm. long . 

 n. Seeds merely pointed or blunt, not caudate q. 

 q. Stamens 3 r. 

 r. Capsule attenuate to tip or subulate, distinctly exceeding the 



calyx ft. 

 s. Heads 2-T-flowered ; capsule not subulate. 



Mature fruit 3.5 mm. long ....... 



Mature fruit 5 mm. long ....... 



. Heads densely many-flowered ; capsule subulate. 



Leaves flattened, obscurely septate ; sheaths without 

 auricles at summit ; cyme large, with widely divergent 

 branches and branchlets ...... 



Leaves terete, distinctly septate ; sheaths with definite auri- 



cles at summit ; branches and branchlets ascending. 

 Blade of the uppermost leaf much shorter than its 

 sheath ......... 



Blade of uppermost leaf much longer than its sheath . 

 f. Capsule shorter than or about equaling the calyx, if longer, 



22. J. brachycephalus. 



24. J. canadensis. 



23. J. brevicaudatus. 



86. J. debiUs. 



8T. J. diffu8is8imu8. 



29. J. polycephalus. 



84. J. megacephalus. 

 38. J. scirpoides. 



abruptly tipped (not subulate) t. 

 t. Capsule half or two thirds as long as the calyx, tapering 



gradually to a conic-subulate beak; glomerules spher- 

 ical ; the rigid subulate sepals much exceeding the 

 petals ; rootstock thick, white, horizontal . . .82. J. braohycarpus 

 t. Capsule nearly equaling or exceeding the calyx, abruptly 

 tipped; glomerules hemispherical; sepals and petals 

 subequal ; sterns tufted or with merely thickened base. 

 Basal leaves abundant, tufted from a thickened base, often 

 elongate and floating, obscurely septate ; stems lax, 

 decumbent or repent, 0.5-2.5 dm. high ; petals blunt 27. J. bulbosus. 

 Basal leaves few, erect ; plant erect, 8 dm. or more high ; 



petals acuminate. 

 Heads 1-50, on ascending-spreading branches; flowers 



3-3.5 mm. long 85. J. acuminattm. 



Heads 200-500, on widely divergent branches ; flowers 



2-2.5 mm. long 88. J. robustus. 



q. Stamens 6 u. 



u. Upper cauline leaves bladeless (or essentially so), consisting 



of firm tawny or colored sheaths 2.5-5 cm. long; the 



middle leaf erect, much overtopping the inflorescence . 28. J. militaris. 



t*. Upper cauline leaves with blades, or. if bladeless, very small v. 



?;.\ Flowers solitary or in 2's, often accompanied or replaced by 



fascicles of small leaves. 



Stem erect, from a horizontal rootstock; flowers secund 

 on the branchlets of a loose dichotomous cyme ; fas- 

 cicles of reduced leaves confined to the inflorescence; 

 anthers much exceeding the filaments . . .25. J. pelocarpus 

 Stem repent or floating, bearing scattered fascicles of re- 

 duced leaves ; roots tufted ; flowers 1 or 2 on axillary 

 or subterminal peduncles ; anthers about equaled by 



the filaments 26. J. subtilis. 



V. Flowers more numerous, in glomerules w. 

 w. Lower leaves elongate, filiform, floating, upper stouter; 

 glomerules mostly bearing fascicles of small leaves ; 



capsule blunt 27. J. bulbosus. 



W- Leaves uniform, none floating ; glomerules without fasci- 

 cles of leaves w. 



