STANDL.EY TREES AND SHRUBS OF MEXICO 1425 



Young branches not white-lanate or arachnoid. 



Stem villous-pubescent above; pappus of about 10 narrowly linear 



awns about 0.3 mm. long 16. S. microchaeta. 



Stem glabrous or merely puberulous above; pappus otherwise. 



Leaves distinctly petioled, the petioles usually 10 to 25 mm. long. 

 Leaves obtuse or obtusish, ovate, crenate-serrate; stem cineras- 



cent-puberulous above 17. S. pyrolaefolia. 



Leaves usually acute to acuminate, if obtusish of diflferent 



shape 18. S. lucida. 



Leaves sessile or on petioles 6 mm. long or less. 



Leaves sessile, very acute, serrate 19. S. connata. 



Leaves short-petioled or with short petioliform bases. 



Pappus awns 2 to 10, nearly or quite equaling the corolla; 

 leaves toothed. 

 Stem thinly velutinous at apex; awns of pappus 10 to 12, 



equaling the achenes 20. S. haenkeana. 



Stem glabrous or sparsely pubescent toward apex; awns of 

 pappus 2 to 5, much longer than the achenes. 



21. S. vernicosa. 

 Pappus awns wanting or solitary. 

 Leaves»entire, 6 cm. long or less. 



Leaves 3.5 to 6 cm. long; squamellae 0.2 mm. long. 



22. S. flourensioides. 

 Leaves 3.3 cm. long or less; squamellae 0.6 mm. long. 



23. S. Integra. 

 Leaves serrate, 7.5 cm. long 24. S. scabrella. 



1. Stevia tephrophylla Blake, Contr. U. S. Nat. Herb. 22: 590. pi. 54. 1924. 

 Known only from the type locality, Los Pinos, Chiapas. 



Shrub about 25 cm. high, branched, densely cinereous-tomentulose; leaves 

 opposite, the blades ovate to oval, obtuse, rather abruptly narrowed into the 

 cuneate-margined petioliform base, 2 to 2.5 cm. long, 7 to 13 mm. wide, crenulate, 

 dull cinerascent-green above, densely cinereous-tomentulose beneath; corymbs 

 very dense, about 2.8 cm. wide, little exceeding the leaves; flowers white; in- 

 volucre 4.8 mm. high; pappus of 2 or 3 awns and about 6 squamellae. 



2. Stevia revoluta Robinson, Proc. Amer. Acad. 44: 617. 1909. 

 Mountains of Puebla; type from Cerro de Gentile, altitude 2,135 to 2,440 



meters. 



Shrubby, about 0.5 meter high, dichotomously branched, densely sordid- 

 puberulous above; leaves opposite, the blades linear-lanceolate, 3.5 to 7 cm. 

 long, 3 to 7 mm. wide, acuminate at each end, entire, usually revolute, subsessile, 

 densely canescent-tomentose beneath, dull green and puberulous above; panicles 

 3.5 to 8 cm. wide; involucre glandular-pilosulous; flowers white; pappus of short 

 lacerate squamellae. 



3. Stevia glandulosa Hook. & Arn. Bot. Beechey Voy. 296. 1840. 

 Sonora, Jalisco, and Tepic; type from Jalisco. 



Shrubby, dichotomously branched, densely and sordidly spreading-pubescent 

 with chiefly gland-tipped hairs; leaves opposite, the blades ovate, 2.5 to 4 cm. 

 long, 1 to 2.2 cm. wide, acutish, rounded-cuneate at base, serrate, densely 

 glandular-pubescent especially beneath, on petioles 0.5 to 1.5 cm. long; heads 

 densely crowded, the panicles 3 to 5 cm. wide; involucre 5 to 7 mm. high, 

 pubescent with both glandular and eglandular spreading hairs; flowers white; 

 pappus of squamellae only. " Merba" (Tepic). 



