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 inflores- 



CGn.cc. 



Stems floating, creeping or diffusely spreading : capsule of a subulate type. 16. J. repens. 

 Stems erect or nearly so : capsule of an obovoid type. 



Perianth at least % longer than the capsule : anthers yellow. 17. J. filipenduhis. 



Perianth equalling or barely exceeding the capsule : anthers reddish 



brown. 



Petals lanceolate to ovate-lanceolate, setiform-acuminate at the apex. 18. /. 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 : 



plants 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. Texanas. 

 Stamens 3, none opposite tne petals : rootstock not tuber-bearing, usu- 

 ally short ana thickened throughout. 

 Uppermost leaf-sheath with an almost obsolete blade, this seldom 



exceeding 1 or 2 cm. in length. 24. J. megacephalus. 



Uppermost leaf-sheath with a normal blade few to several cm. in 



length. 



Stamens as long as the petals, the anthers exserted between them. 25. /. 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 %-% as long as the perianth. 28. J. br achy carpus. 



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 % their length. 29. /. 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 % 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 : plants 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 % ex- 

 ceeding the perianth. 35. J. debttis. 



1. Juncus effusus L. Plants 5-12 din. 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 obloug-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. 



