260 MEMOIRS OF THE NEW YORK BOTANICAL GARDEN [VOL. 10 



3. Involucre 35 mm high; calyx and hypanthium 20 mm long; corolla 42 mm long, 



the tube nearly three times the length of the lobes; Colombia. S. luxurians. 



2. Involucre 18 mm or less high, not concealing the flowers at anthesis. 



4. Summit of peduncle and/or involucre pubescent. 



5. Outer surface, at least in part, and summit of calyx pubescent. 



6. Involucre glabrous externally; summit of calyx densely papillose-ciliolate, 

 the upper portion of the outer surface densely papillate cano-pulveru- 

 lent; petioles and lower surface of loaf -blades glabrous; Colombia. 



S. cuatrecasasii. 



6. Involucre densely puberulous externally; calyx externally pilosulous; 



petioles and lower surface of leaf -blades pubescent; Colombia. S. puberula. 

 5. Outer surface and summit of calyx wholly glabrous. 



7. Peduncle 3.5-10.5 cm long; heads 25-40 -flowered ; involucre 7-10 mm 



long; Venezuela. S. nilssonii. 



7. Peduncle 1 cm or less long; heads about 4-flowered; involucre 13-17 mm 



long; Colombia. S. acuminata. 



4. Summit of peduncle and involucre glabrous. 

 8. Stigmas 4. 



9. Flowers 8-merous; calyx with usually 8 or more irregular dentieulations 



at summit; peduncle solitary; Jamaic;i. S. involucrata. 



9. Flowers 6-merous; calyx truncate, the lobes, if any, obsolete or in fruit 



more evident; peduncles usually three, sometimes one; British Guiana. 



S. ternata. 



8. Stigmas 2-3. 



10. Leaves obovate, broadest toward apex or in upper half and broadly 

 rounded to subtruncate at apex; Colombia. S. rotandata. 



10. Leaves otherwise, broadest at middle or base, tapering or narrowed to an 

 acute or acuminate or to an obtuse or rounded apex. 

 11. Midrib of lower side of leaf partly or wholly pubescent. 



12. Corolla rotate, the lobes slightly longer than the tube; leaf-blades 

 ovate-elliptic or broadly elliptic, 2.7-5.5 cm broad, 6.5-8.5 cm long; 

 Colombia. 8. acuminata. 



12. Corolla salverform, the lobes obtuse, shorter than .the tube; leaf- 

 blades narrowly elliptic-oblong, 2.5-3.5 cm broad, 8.5-10.5 cm long; 

 Colombia. S. caciiminis. 



11. Midrib of lower side of leaf completely glabrous. 

 12. Peduncles 2 or more at a node. 



13. Heads robust, 3-3.5 cm broad, 2-2.5 cm high in fruit; leaf -blades 

 abruptly acute to acuminate at apex, 13-15.5 cm long, 5-8 cm 

 broad; Venezuela. S. bipedunculata. 



13. Heads smaller, 1-2.5 cm broad, 1-2 cm high in fruit; leaf-blades 

 rounded or obtuse to subacute at apex, 5-12 cm long, 2-5 cm 

 broad. 



14. Corolla-tube rotate, 3.5 mm long, shorter than the lobes; inner 



reflexed cucullate appendage of corolla-lobes located just below 

 the apex ; flowers often 4-merous ; orifice of corolla with a dense 

 brush of erect hairs; involucre 2.5 mm long (high) ; Venezuela. 



S. suaveolens. 



14. Corolla-tube salverf orm-tubular, 8-11 mm long, usually longer 

 than, or sometimes equaling, the lobes ; inner reflexed cucullate 

 appendage of corolla-lobes located 4-5 mm below apex ; flowers 

 5-6-merous; orifice of corolla naked, the tube pubescent below 

 orifice; involucre 3-8 mm long (high), Guianas; Brazil. 



S. polycephala. 



12. Peduncles solitary at a node. 

 15. Peduncle 0.5-1 cm long. 



16. Petioles 0.3-0.5 cm long; leaf -blades 1-2.3 cm broad. 



17. Lateral nerves on lower surface of leaf-blades obsolete or 

 nearly so; leaf -blades abruptly acute to subacuminate, ovate- 

 elliptic or elliptic-ovate chiefly; interior of corolla-tube partly 

 puberulous; involucre 2-3 mm high; Venezuela. S. maguirei. 



