762 CONTRIBUTIONS FBOM THE NATIONAL HERBARIUM. 



Leaves cuneate to rounded at base, rarely shallowly cordate, never 

 velutinous. 



Carpels each with 2 long retrorsely barbed awns 13. S. salviaefolia. 



Carpels not awned, or the awns short and not barbed. 

 Leaves linear or linear-oblong. 

 Carpels rounded at apex ; leaves pubescent on the upper surface. 



14. S. neomexicana. 

 Carpels acute or short-awned ; leaves usually glabrous on the 



upper surface 15. S. lindheimeri. 



Leaves broader than linear-oblong, often ovate. 



Pedicels jointed below the middle; leaves distichous 16. S. acuta. 



Pedicels jointed above the middle, or sometimes not jointed; 

 leaves not distichous. 

 Flowers chiefly racemose, the subtending leaves bractlike. 



17. S. xanti. 

 Flowers axillary. 

 Pedicels much longer than the subtending leaves. 



18. S. potosina. 

 Pedicels all or mostly shorter than the leaves. 

 Stems and calyx sparsely hirsute; leaves shallowly cordate 



at base 19. S. tragiaefolia. 



Stems and calyx not hirsute; leaves cuneate or rounded at 

 , base. 



Calyx lobes acute and mucronate ; stipules not ciliate. 



20. S. rhombifolia. 

 Calyx lobes cuspidate-acuminate; stipules long-ciliate. 



21. S. corymbosa. 

 Carpels 5 or sometimes 6. 



Flowers densely glomerate in the leaf axils or on the branches of a 

 panicle. 



Leaves hirsute beneath 22. S. urens. 



Leaves stellate- velutinous beneath 23. S. aggregata. 



Flowers solitary in the axils or loosely paniculate, never in dense glome- 

 rules. 

 Leaves rounded or obtuse at base, rarely subcordate, oblong or linear- 

 oblong 24. S. angustifolia. 



Leaves cordate at base, usually deeply so, broader than oblong. 

 Leaves mostly rounded or obtuse at apex, rarely acute, usually 2 cm. 



long or less 25. S. procumbens. 



Leaves acuminate or long-acuminate, usually much more than 2 cm. 

 long. 



Leaves very asymmetric at base 26. S. decumbens. 



Leaves symmetric at base. 



Stems viscid-pilose above 27. S. glutinosa. 



Stems usually without viscid pubescence 28. S. glabra. 



1. Sida ciliaris L. Syst. Nat. ed. 10. 1145. 1759. 



Sida muricata Cav. Icon. PI. 6: 78. pi. 597, f. 1. 1801. 



Sinaloa and Jalisco to Oaxaca and YucatSn. Texas, West Indies, Central 

 America, and South America. 



Plants chiefly herbaceous and spreading, the branches stellate-strigose ; leaves 

 mostly 1 to 2 cm. long, obtuse, rounded at base, serrate, glabrous above, stellate- 

 pubescent beneath ; bracts subulate, long-ciliate ; petals copper-colored ; carpels 

 about 7. 



