OF ARTS AND SCIENCES. 37 



datis ; pappo ex arista unica elongata rariter denticulata et setis tenui- 

 bus brevibus. — Old fields, near the city of San Luis Potosi, August. 

 No. 4"j0. Intermediate in character between Perymenium and Me- 

 lanthera, it might be placed among the radiate yellow-flowered species 

 of the latter ; but the almost mature heads are not globular, and 

 the involucre remains erect. Only the simpler and more herbaceous 

 involucre distinguishes the plant from true Perymenium. 



Encelia MicuoriiVLLA. Fruticulosa (pedalis), scabro-puberula ; 

 ramis floridis (spithamseis) apice nudo pedunculiformi monoceplialis ; 

 foliis alternis (semipollicaiibus) viridibus coriaceis ovato- seu oblongo- 

 lanceolatis cuspidato-acuminatis basi acutis vix petiolatis integerrimis 

 penuinerviis concoloribus inter venas primarias minutim reticularis ; 

 involucri bracteis lanceolatis ; ligulis 6-7 ; acheniis villosissimis exa- 

 latis obovatis apice parum emarginatis ; pappo nullo. — Gravelly hills 

 near Saltillo, August. No. 462. 



HELIANTHELLA Mexicana. II. Parryi sat similis, gracilior, 

 monocephala, parce hispida ; foliis etiam radicalibus (3-pollicaribus 

 lin. 2-3 latis) lineari-lanceolatis obsolete triplinerviis, caulinis pollicari- 

 bus ; capitulo pro genere parvo ; involucro magis folioso; corollis disci 

 atropur{)ureis ; acheniis immaturis faciebus marginibusque villosissimis 

 apice scarioso-bidentatis cum coronula hyalina parva pluripartita. — 

 In the valley of Mexico, July. No. 463. Head barely half the size 

 of that of Helianthella Parryi, and apparently erect, not nodding on 

 the apex of the stem. 



Verbesina sororia. V. Siegesbeckice sat similis; sed caule aptero; 

 foliis vix petiolatis magis pubescentibus hand triplinerviis ; floribus radii 

 styliferis sed steritibus ligula ampliore ; acheniis disci ala lata subincisa 

 marginatis. — Wooded mountain slopes, near San Luis Potosi, August. 

 No. 466. V. Siegesbeckia forms an exception to the character 

 " achenia distincte bialata " in the Genera Plantarum ; and the distinc- 

 tion between Verbesina and Actinomeris is failing ; for at least two 

 species referred to the latter are frequently provided with a well- 

 formed style to the ray-flowers, jet with the ovary sterile, as in the 

 present plant. The likeness of the latter to V. (Phcethusa) Sieges- 

 beckia is striking, notwithstanding the wingless stem and the broadly 

 winged achenia. 



Verbesina hypoleuca. Verbesinaria, Apterce DC. ; caule virgato 

 bipedali e basi suffrutescente cinered-puberulo apice nudo paniculatim 

 oligocephalo ; foliis lanceolato-oblongis (eirc. bipollicaribus) penuiner- 

 viis grosse dentatis basi plerumque angustata integriuscula arete 

 auriculato-sessilibus supra velutino-puberulis subtus albo-tomentosis, 



