, 
JUNCACEAE 255 
** Leaf-blades terete, channeled along the upper side. 
Lowest bract less than 4 times the length of the inflorescence: capsule 
oblong or obovoid, with the ordinary dehiscence. 14. J. dichotomus. 
Lowest bract rarely less than 4 times the length of the inflorescence: 
capsule globose-ovoid, breaking up irregularly in age. 15. J. setaceus. 
b. Flowers not bibracteolate, in true heads on the branches of the infiores- 
cenee. f 
Stems floating, creeping or diffusely spreading: capsule of asubulate type. 16. J. repens. 
Stems erect or nearly so: capsule of an obovoid type. 
Perianth at least 44 longer than the capsule: anthers yellow. 17. J. filipendulus. 
ee equalling or barely exceeding the capsule: anthers reddish 
rown. 
Petals lanceolate to ovate-lanceolate, setiform-acuminate at theapex. 18. J. setosus. 
Petals obovate to oblong, broadly obtuse at the apex and sometimes 
slightly mucronate. 
Heads of the inflorescence commonly 5-15, usually 5-10-flowered : 
lants mostly less than 5 dm. tall. 19. J. marginatus. 
Heads of the inflorescence numerous, except in depauperate 
plants, usually 2-5-flowered : plants mostly over 5 dm. tall. 20. J. aristulatus. 
B. Leaf-blades either terete and not channeled, or flattened or compressed, with 
the flat surfaces not facing the stem. 
Leaf-blades terete, the pith perforated with slender tubes: clusters of the 
inflorescence reduced to a single flower each. 21. J. abortivus. 
Leaf-blades either terete, hollow, and provided with node-like septa, or flat- 
tened or compressed, or both: clusters of the inflorescence few-many- 
flowered. 
Capsule truly subulate. 
Stamens 6, one opposite each sepal and petal: rootstock slender, tuber- 
bearing at intervals. 
Stem stout : sepals longer than the petals : capsules barely exceeding 
the perianth, each with a beak 1-1.5 mm. long. 22. J. Torreyi. 
Stem slender: sepals shorter than the petals : capsules conspicuously 
exserted from the perianth, each with a beak 1.5-2 mm. long. 23. J. Texanus. 
Stamens 3, none opposite the petals: rootstock not tuber-bearing, usu- 
ally short and thickened throughout. 
Uppermost leaf-sheath with an almost obsolete blade, this seldom 
exceeding 1 or 2 em. in length. 24. J. megacephalus. 
SPP e leaf-sheath with a normal blade few to several cm. in 
ength. 
Stamens as long as the petals, the anthers exserted between them. 25. J. scirpoides. 
Stamens considerably shorter than the petals: anthers included. 
Leaf-blades flattened and usually with incomplete septa: cap- 
sules markedly beaked, the valves in dehiscence curved 
outward in the middle, but united above by the beak. 26. J. polycephalus. 
Leaf-blades slightly compressed, the septa complete : capsules 
beakless, the valves separating throughout in dehiscence. 27. J. validus. 
Capsule oblong to linear-lanceolate in outline, obtuse or acute at the apex, 
or sometimes mucronate, but not truly subulate. 
Capsules 12-27 as long as the perianth. 28. J. brachycarpus. 
Capsules equalling the perianth in length or exceeding it. 
Seeds 0.7-2.5 mm. long, the body tapering at either end into a white 
tail of varying length. 
Plant rigid throughout: stems 2-4 mm. in diameter: sepals and 
petals spinescent: capsules dark red, firm, exceeding the 
perianth by about V5 their length. 29. J. trigonocarpus. 
Plant with none of its parts unusually stiff or hard : stems less 
than 2 mm. in diameter, or the capsule not exserted from the 
perianth by more than 1 mm. 30. J. Canadensis. 
Seeds 0.35-0.55 mm. long, the body with a short, rather abrupt, pap- 
illa-like, usually dark-colored apiculation at either end. 
Capsules nearly twice the length of the perianth, the two together 
3.5-5 mm. long. . 31. J. diffusissimus. 
Capsules equalling or sometimes about 14 exceeding the perianth, 
the two together 2-3.5 mm. long. 
Perianth 2-2.5 mm. long. 
Larger basal leaf-blades with more than 40 septa: capsule 
green or straw-colored : peu usually over 5 dm. tall. 32. J. robustus. 
Larger basal leaf-blades with less than 40 septa: capsule 
dark brown above at maturity. 33. J. Elliottii. 
Perianth 2.5-3.5 mm. long, or if less the capsule straw-colored 
at maturity and the whole plant less than 5 dm. tall. 
Sepals and petals 2.5-3.5 mm. long: capsules ovoid-lanceo- 
late in outline, broadly acute and mucronate, about as 
long as the perianth. : 34. J. acuminatus. 
Sepals and petals 2-2.5 mm. long : capsules linear-lanceolate 
in outline, obtuse and merely apiculate, about 14 ex- 
ceeding the perianth. 35. J. debilis. 
1. Juncus effisus L. Plants 5-12 dm. high, densely tufted. Leaves basal, reduced 
to filiform rudiments few mm. long : inflorescence 2-10 cm. high, occasionally congested ; 
its bract erect, appearing like a continuation of the scape, 5-25 cm. long: perianth 2-3 
mm. long: sepals and petals lanceolate, acuminate : stamens 3; anthers shorter than the 
filaments : capsules obovoid or oblong-obovoid, about as long as the perianth, 3-celled, 
regularly dehiscent. 
In swamps and low grounds, nearly through the United States and southern British America. 
Also in Europe and Asia. Spring to fall. 
