180 MISC. PUBLICATION • 42 3, U. S. DEPT. OF AGRICULTURE 



4. Stems terete; leaf blades none or reduced to filiform rudiments (5). 



5. Perianth segments 2 to 3 mm. long, straw-colored to pale brown; 

 stamens 3; anthers not longer than the filaments; capsule obovoid, 

 obtuse or refuse 2. J. effusus. 



5. Perianth segments 3.5 to 5 mm. long, purplish brown; stamens 6; 

 anthers much longer than the filaments; capsule narrowly ovoid, 



acute, mucronate 3. J. balticus. 



3. Stems very coarse, stout and rigid; flowers in headlike clusters arranged 

 in open panicles, from the axil of a single bractlet but without brac- 

 teoles (6). 

 6. Perianth segments acutish to acuminate, narrowly scarious-margined, 

 greenish or straw-colored, 4 to 6 mm. long, nearly equaling the 



narrowly ovoid, acute or acuminate capsule 5. J. cooperi. 



6. Perianth segments (at least the inner ones) obtuse or truncate, broadly 

 scarious-margined, brown, 2 to 4 mm. long, much shorter than the 



subglobose, obtuse, mucronate capsule 6. J. acutus. 



1. Inflorescence obviously terminal (or, if not, then the leaves septate and the 

 involucral bracts flat or channeled along the upper side) ; involucral bracts 

 leaflike, not stiffly erect or resembling a continuation of the stem (7) . 

 7. Leaf blades transversely flattened (inserted with the flat surface facing the 

 stem), or in age involute, not septate (8). 

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

 pedicel (9). 



9. Stamens 3 ; perianth 2 to 3 mm. long 13. J. margin atus. 



9. Stamens 6; perianth 5 to 6 mm. long (10). 



10. Outer perianth segments equaling or slightly exceeding the inner 



ones; auricles of the leaf sheaths 0.5 to 1.5 mm. long; leaf blades 



flat; anthers cream-colored or pale yellow, _ 14. J. longistylis. 



10. Outer perianth segments shorter than the inner ones; auricles of the 



leaf sheaths 1.5 to 3 mm. long; leaf blades channelled; anthers 



brownish 15. J. macrophyllus. 



8. Flowers inserted singly on the branches of the inflorescence (not in heads) , 

 each with a pair of bracteoles at base in addition to the bractlet at 

 base of the pedicel (11). 

 11. Inflorescence more than half the height of the plant; flowers scattered 

 along the loose forking branches; low annuals (12). 

 12. Capsule oblong, 3 to 4.5 mm. long; perianth 4 to 6 mm. long. 



7. J. BUFONIUS. 



12. Capsule subglobose to broadly ovoid; perianth 3 to 4 mm. long. 



8. J. SPHAEROCARPUS. 



11. Inflorescence much less than half the height of the plant; perennials 

 (13). 



13. Capsule completely 3-celled, refuse 9. J. confusus. 



13. Capsule 1-celled with septa extending halfway to the center, acutish 



to obtuse, not refuse (14). 

 14. Auricles at summit of the sheaths very thin, white and scarious, 

 conspicuously produced beyond the point of insertion, 1 to 3.5 



mm. long; bracteoles blunt 12. J. macer. 



14. Auricles at summit of the sheaths firm, not conspicuously pro- 

 duced beyond the point of insertion (15). 

 15. Bracteoles blunt; auricles cartilaginous, yellow, very rigid 

 and glossy, especially the short produced portion. 



10. J. DUDLEYI. 



15. Bracteoles acuminate to aristate; auricles with the very slightly 



produced portion membranaceous, not rigid, easily broken. 



11. J. INTERIOR. 

 7. Leaf blades terete or ensiform (flattened and inserted with one edge facing 

 the stem), not transversely flattened (16). 

 16. Leaf blades terete, the septa complete (17). 

 17. Capsule subulate; stamens 6 (18). 



18. Plant low, 10 to 40 cm. high; leaf blades erect or ascending; flowers 

 3 to 4 mm. long; inner perianth segments equaling or exceeding 



the outer ones 16. J. nodosus. 



18. Plant taller, 40 to 100 cm. high; leaf blades divaricate; flowers 4 to 

 5 mm. long; inner perianth segments shorter than the outer ones. 



17. J. TORREYI. 



