78 JUNCACEAE. 



A. Leaves neither septate nor equitant. 

 i. Leaves not fistulose ; flowers many. 



a. Flowers bracteolate, inserted singly on the branches of the inflores- 

 cence ; leaves narrowly linear, either flat or subterete and channeled. 



a. Perennials; stem simple (TENUES). 



Seeds long, caudate ; leaves subterete, with a shallow groove above. 



7. /. Vaseyi. 



Seeds not caudate ; leaves flat, but often involute ; lunate in cross- 

 section. 

 Auricles at the summit of the sheaths membranous, whitish ; petals 



and sepals scarcely spreading. 

 Auricles scarcely produced beyond the insertion, scarcely scarious ; 



inflorescence open. 

 Perianth 3-4 mm. long, equalling the capsule. 



8. /. interior. 

 Perianth 4.5-5 mm. long, exceeding the capsule. 



9. /. arizonicus. 

 Auricles conspicuously produced beyond the point of insertion ; 



flowers few, congested. 10. /. confusus. 



Auricles cartilaginous, yellowish-brown ; petals and sepals spread- 

 ing, ii. J. Dudleyi. 

 |8. Annuals; stem branching (BuroNii). 12. /. bufonius. 



b. Flowers not bracteolate, in true heads on the branches of the inflores- 

 cence; leaves broad and grasslike (GRAMINIFOLII). 



13. /. longistylis. 



2. Leaves fistulose (i. e., hollow) ; flowers few, in small heads (CASTANEI). 

 Stem leafy only at the base, but the uppermost leaf often with a long 

 sheath ; petals and sepals about 4 mm. long ; leaves about i mm. in 

 diameter ; lower bract of inflorescence membranous. 



14. /. trighimis. 



Stem more or less leafy ; leaves about 2 mm. in diameter ; perianth 5-6 

 mm. long; lower bracts foliaceous. 15. /. castaneus. 



B. Leaves septate. 



1. Leaves terete, not equitant. 



a. Septa poorly developed; heads 1-3 (see /. triglumis and 7. castaneus). 



b. Septa well developed ; heads usually several (in /. Mertensianus usually 



only i) (NODOSI). 

 Inflorescence with short branches ; flowers echinate-spreading or the 



lowest of the head reflexed ; capsule narrowly lanceolate. 

 Heads 7-8 mm. in diameter; leaf-blades erect; petals usually longer 



than the sepals. 16. /. nodosus. 



Heads over 10 mm. in diameter; leaf -blades usually spreading; sepals 



longer than the petals. 17. T. Torreyi. 



Inflorescence with elongated branches or in /. Mertensianus with a single 



head ; flowers erect-ascending ; capsule oblong. 

 Heads several ; leaves terete ; seeds not caudate. 



1 8. J. truncatus. 



Heads solitary or rarely 2-3 ; leaves somewhat flattened ; seed usually 

 caudate. 19- 7. Mertensianus. 



2. Leaves equitant, laterally flattened, so that one edge is towards the stem 



(ENSIFOLII). 

 Flower-clusters numerous, small, 5-i2-flowered, light-colored. 



20. 7. brunnescens. 

 Flower-clusters few, is-25-flowered. 



Flowers greenish or light-brown; ligules of the sheath usually without 



auricles. 21. 7. porous. 



Flowers fuscous or very dark-brown ; ligules of the sheath produced into 

 small auricles. 22. 7. saximontanus. 



i. Juncus filiformis L. In wet places from Lab. to Alaska, Pa., Utah and 

 Wash. Reported from Colorado (Coulter}, but doubtful. 



