656 PROCEEDINGS OF THE AMERICAN ACADEMY 



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oribus parce hispidis breviter foliaceis ; ligulis brevibus aurantiacis ; 

 pappi squamellis lineari-oblongis coriaceis, aristis parum scabris. T. 

 tubceformis Bot. Mex. Bound, p. 90, non Cass. — Magdalena, in tbe 

 Mexican province of Sonora, Thurber, no. 910. This species is indi- 

 cated by Benthara, in Gen. PL p. 375. In the genus now reduced to its 

 natural proportions and well characterized, it is the smallest flowered 

 species, the heads being only half an inch long, and the ligules short. 



Flourensia DC. As to F. corymbosa, if C. Gay's plant of the 

 name is genuine, it is clearly a Viguiera (as that genus is now well 

 characterized by Bentham), and the character " achenia villosissima " 

 (DC) is not applicable, as it is to the genuine species. These I can- 

 not regard as belonging to Helianthus, They appear to be quite dif- 

 ferent in habit, and hardly less so in the style, corolla, and achenia ; 

 and the pappus, seemingly not caducous even in F. thurifera, is mar- 

 cescent in the more genuine discoid species, F. laurifolia, and per- 

 sistent in the anomalous F. cernua. F. laurifolia and F. thurifera 

 are not so very dissimilar in habit ; both have the chaffy awns of the 

 pappus disposed to be trifid, and want the accessory nerves to the 

 corolla. F. cernua, which shows these nerves, but is otherwise most 

 unlike Helianthus, and has turgid instead of flat achenia, still accords 

 with Flourensia in most respects. 



Encelia Adans. The combination which I had proposed of 

 Gercea and Barrattia with Sinisia is justly carried a step further by re- 

 ferring all these to sections of Encelia. I have detected rudimentary 

 awns to abortive ray-achenia in specimens which in Bot. Mex. Bound. 



1 had referred to E. conspersa Benth. (a species still obscure), but 

 should now regard as a mere variety of E. Californica. This species 

 is distinguished from the Chilian E. oblongifolia by the leaves more 

 obtuse at base, and the achenia with a much shallower emargination. 

 The species of the section Gercea are : — 



Encelia (Gercea) nudicaulis. Herbacea, pube brevi densa ar- 

 genteo-canescens ; foliis omnibus radicalibus orbicularis integerrimis basi 

 3-5 nervata in petiolum nudem latiusculum longum subito angus- 

 tatis ; scapo subpedali prorsus nudo monocephalo ; involucri incani lati 

 squamis triseriatis lanceolatis discum subtequantibus ; ligulis ultra 20 

 lanceolatis pollicaribus cum floribus disci aureis ; acheniis obovatis 

 undique villosissimis marginibus apiceque callosis ; pappo ex aristis 



2 subulatis sat validis pilos hand superantibus et squamellis intermediis 

 minimis plurimis e membranulo fere continuo brevissimo ortis. — 



