EUPATORIUMS OF PERU. 



71 



Sect. III. ExiMBRiCATA (DC.) HofFm. (See Robinson, Proc. Am. 



Acad. liv. 303.) 



Key to Species. 



a. Heads 3-10-flowered b. 



b. Leaves pinnately veined 58. E. exserto-venosum. 



b. Leaves 3-5-nerved from or somewhat above the base. 

 Branchlets and leaves glabrous; at least the lower teeth of 



the leaves widely spreading and very acute. 

 Petioles about 2 mm. long; leaf -blade about 8 mm. 



wide 59. E. chilca. 



Petioles 8-10 mm. long; leaf-blade about 1.6 cm. wide. 



60. E. affine. 

 Branchlets and leaves puberulent or pubescent, sometimes 



glandular-puberulent 61. E. hepianthum. 



a. Heads 12- oc-flowered c. 



c. Leaves sessile, but the blade gradually narrowed to a pet- 



iole-like base, thickish; involucral scales rounded at tip, 



grayish-velvety . .39. E. Commersonii. 



c. Leaves on wingless usually slender though sometimes short 

 petioles d. 



d. Leaves entire, large, 8-10 cm. wide 62. E. uber. 



d. Leaves crenate to serrate, rarely more than 6 cm. wide e. 

 e. Leaves acute or acuminate at the base /. 

 /. Leaves 3-nerved from or somewhat above the base. 

 Heads 1.3-14-flowered; leaves 3-4.5 cm. long, on 



petioles 4-6 mm. in length 63. E. cuzcoesne. 



Heads 20-25-flowered ; leaves at maturity 5-8 cm. 



long, on petioles 1-2.5 cm. in length. 



Scales of the involucre loosely ciliate toward the 



the tip with jointed hairs; petiole pubescent, 



1-2.5 cm. long; serratures 5-12 on each side of 



the leaf-blade 64. E. tambillense. 



Scales nearly or quite glabrous toward the tip; 

 petiole minutely puberulent and sparingly 

 muriculate, at most about 1 cm. long ; serratures 

 11-23 on each side of the leaf-blade. .65.. E. stidophyllum. 



f. Leaves pinnately veined. 



Involucral scales linear, attenuate; leaves mem- 

 branaceous 6Q. E. simulans. 



Involucral scales narrowly oblong, obtuse to 

 rounded at tip; leaves coriaceous, with prominent 



reticulation on both .surfaces 57. E . Jastigiatum. 



e. Leaves obtuse to cordate at base g. 



g. Leaves pinnately veined 27. E. endytum. 



g. Leaves 3-5-nerved from or somewhat above the 



base h. 

 h. Stems villous to hispid-pubescent with widely 

 spreading and jointed hairs i. 

 i. Petioles rarely over 2 mm. long, about one- 

 tenth the length of the leaf-blade ...... .67. E. cutervense. 



i. Petioles 5-25 mm. long, mostly one-sixth to 

 two-thirds the length of the leaf-blade j. 



