30 PROCEEDINGS OF THE AMERICAN ACADEMY 



Ch.enactis Fremonti. GUibrata vol glabra, pedalis ; foliis aii- 

 gusto-liuearibus aut integerrimis aut lobis 'S-o instriictis ; cajjitulis 

 paucis ulua-seiuipollicaribus ; iiivolucri bracteis crassiusculis acutius- 

 culis, costu prominula; coroUis albido-carneis, marginalibus limbo 

 eximie ampliato uunc in ligulam veram 5-lobam expanso discum su- 

 perante ; pappi paleis 4 liueari-lanceolatis corollara subitquantibus 

 costa basilar! mox evanida instructis. — Desert of the Mohave and 

 Lower Colorado, Fremont (imperfect specimen), Newberry, Parish, 

 Lemmon. A very distinct species, with the aspect rather of C. 

 Xantiana, but in character nearer C. stevioides, with wliicli it has 

 been somewhat confounded. It is the most radiatiform of all the 

 species, the palmato-ampliate limb of the marginal corollas not rarely 

 developed into a short and broad ligule, with live equal and parallel 

 lobes. 



Cii.TiNACTis Nevii. This name is given to a yellow-Howered 

 species, imperfectly known by a single specimen collected in Idaho 

 by Rev. R. D. Nevius, resembling C. heterocarpha, but with obsolete 

 jia^pus. 



CiiiENACTis TiiYSANOCAKPHA. (§ AcARPHiEA, character amplif. 

 Pappus aut nuUus, aut deciduous. Achenia subclavata, complauata, 

 nigricantia. Ahume, involucro viscido, corollis albidis, marginalibus 

 baud am[)liatis.) Humilis, gracilis, viscida-puberula, usque ad capitu- 

 lum parce foliosa ; foliis linearibus angustis integerrimis'; involucri 

 7-10-tlori bracteis lineari-oblongis ; acheniis clavato-obovatis ; pappo 

 corolla dimidio breviore deciduo, e paleis 8-9 tenuibus spathulatis 

 eroso-fimbriatis. — Southern part of the Sierra Nevada, California, 

 probably in Kern Co., at 9,800 feet, Rothrock, no. 34o. 



PoLTPTERlS, Nutt. Nuttall's genus, founded on P. hitegrifolia, in 

 our opinion, ought not to have been merged in Palafoxia, Lag. It is 

 distinguished by the scarious-membranaceous or petaloid-colored tips 

 of the involucral bracts (in the manner of Florestina), and by the 

 division of the limb of the coi'olla almost down to the filiform tube ; 

 moreover the style-branches are not so much like those of Eupa- 

 toriacecE. Our species fall under three sections. The first, and near- 

 est to Florestina, has middle-sized or small and hoinogamous heads ; 

 involucral bracts herbaceous up to the short sphacelate-colored tips ; 

 corolla-limb parted down to the slender tube ; akenes oblong-pyramidal ; 

 and root aniuial. Here, P. callosa {Sfevia callosa, Nutt., J^alafoxia 

 caUasa, Torr. & Gray), P. Texana {Palafoxia, DC, &c.), and the 

 IMexican P. Lindenii. The second section, with heterogamous and 

 palmately i-adiate heads, slender akenes, and an annual root, contains 



