Juncus Juncaceae 291 



Ultimate floriferous branchlets widely spreading, 0.5-2 cm long.... 



7a. J. macer f. Williamsii. 



Ultimate floriferous branchlets elongate and ascending. 



Ultimate floriferous branchlets rarely over 4 cm long; sepals 

 and petals mostly subequal; capsule averaging three fourths 

 the length of the acuminate sepals; plant generally stout. . . . 



7b. J. macer f . anthelatus. 



Ultimate floriferous branchlets often 7 cm long; sepals attenuate- 

 subulate, usually conspicuously longer than the petals; 

 capsule averaging half the length of the sepals; plant gen- 

 erally slender, often lax 7c. J. macer f. discretiflorus. 



Auricles at the summit of the sheaths firm, not conspicuously produced 

 beyond the point of insertion. 



Bracteoles acuminate to aristate; auricles with the very slight- 

 ly produced portion membranaceous, not rigid (easily 

 broken), stramineous, often tinged with brown or light 

 red, occasionally somewhat cartilaginous along the sides 

 below the summit; inflorescence generally loose; perianth 



from appressed to slightly spreading 8. /. interior. 



Bracteoles blunt to acute; auricles cartilaginous, yellow, be- 

 coming brown with age, very rigid and glossy, especially 

 the short produced portion; inflorescence generally com- 

 pact; perianth widely spreading 9. J. Dudleyi. 



Flowers in heads, not bracteolate, i.e., with only the bractlet at the base of the 

 pedicel. (Section Graminifolii.) 

 Stamens not exserted in fruit; perianth exceeding the obovate, usually dull 

 capsule; heads few (2-20), flowers many (5-10) in a head; culms cespitose, 



bulbous at base 10. «/. marginatus. 



Stamens exserted in fruit; perianth usually shorter than the ovoid, shining 

 capsule; heads numerous (20-100); flowers few (2-6) in a head; culms 

 solitary or few together from an elongate, nodulose rhizome; plant taller 

 and coarser. 



Inflorescence loose; heads remote, 2-3 (rarely 6)-flowered 11. J. bifloms. 



Inflorescence compact; heads approximate, 3-6-flowered 



11a. J. bifiorus f. adinus. 



Leaves terete, hollow, septate. (Section Septati.) 

 Seeds with tail-like appendages. 



Heads few to many; flowers 5-50 in a head; flowers with mature fruit about 4 

 mm long; perianth segments subulate-tipped; capsule equaling or moder- 

 ately exceeding the calyx; seed (including tails) 1-1.8 mm long, with con- 

 spicuous tails 12. J. canadensis. 



Heads numerous in a diffuse panicle; flowers 3-5 in a head; flowers with 

 mature fruit 2.5-3.5 mm long; perianth segments obtuse or nearly so, 

 scarious-margined, less rigid; capsule usually much exceeding the calyx; 



seed (including tails) barely 1 mm long, the tails very short 



13. J. brachycephalus. 



Seeds without tail-like appendages. 

 Stamens 3, opposite the sepals. 



Capsule tapering evenly to the tip or subulate-beaked, distinctly exceed- 

 ing the calyx. 

 Heads numerous; flowers 2-7 in a head; inflorescence very large and 



diffuse; capsule gradually attenuate 14. J. diffusissimus. 



Heads few; flowers very numerous in a head; capsule subulate 



15. J. scirpoides. 



Capsule obtuse or acute at the apex, from shorter than to slightly exceed- 

 ing the calyx. 



