EUPATORIUMS OF PERU. 43 



specific, and varietal descriptions in the author's recent paper on the 

 Eupatoriums of Colombia, Venezuela, and Ecuador. In the case of 

 Peru\'ian species and varieties not occurring in any of these countries 

 and therefore not described in the paper just mentioned, diagnoses are 

 here given. Thus, by the use of the two papers together, anyone 

 desiring to identify a Peruvian Eitpatorimn will be able to consult a 

 fairly detailed diagnosis of each species and variety of the genus thus 

 far known from the country. 



Sect. I. Cylindrocephala DC. (See Robinson, Proc. x\in. Acad. 



liv. 270.) 



Key to Species. 



a. Involucral scales squarrose, considerably altered in texture 

 and somewhat spreading at the subtruncate or very bluntly 

 pointed tip; leaves linear or narrowly oblong, nearly or quite 



sessile 1. E. ivaefolium. 



a. Involucral scales closely appressed at the often darkened 

 but not greatly modified tip; leaves lanceolate to deltoid- or 

 rhombic-ovate, petiolate b. 

 b. Heads solitary, long-pedicelled; leaves scabrous above, 



glabrous beneath; habit of § Praxelis 2. E. serratuloides. 



b. Heads corymbose or cymose-paniculate; leaves never 

 pubescent above if glabrous beneath c. 

 c. Heads 40-50-fiowered ; leaves small, lanceolate, 2.5- 



3.5 cm. long Z. E. eripsimum. 



c. Heads 7-35-flowered ; leaves (except in E. squalidum) 

 rarely less than 4 cm. long d. 

 d. Pedicels glabrous or at most minutely granulated, 

 furrowed; leaves glabrous on both surfaces, elliptical 



to rhombic, acute at both ends, thickish 4. E. laevigatum. 



d. Pedicels (when developed) pubescent e. 



e. Heads very slender, 7-10-flowered, acute in bud /. 

 /. Involucre essentially glabrous; leaves attenuate- 

 cuneate at base, mostly thin and nigrescent in 

 drying 5. E. leptocephalum. 



f. Involucral scales (at least when young) definitely 



pubescent, especially toward the dark and mu- 

 cronulate tip; leaves subrotund or only shortly 

 cuneateat base, thickish-membranaceous, drying 



green 6. E. ten uicapitulatum. 



e. Heads thicker, mostly 1.5-35-flowered, obtuse in 

 bud g. 



g. Heads about 8 mm. long, borne in a leafy pan- 



icle; leaves 1.5-4 cm. long; petioles 1-4 mm. 



long 7. E. squaliilum, v. Rusbyanum. 



g. Heads 1-1.2 cm. long; leaves 6-10 cm. long on 

 petioles (except in E. scabrum) 1-2 cm. long h. 



