CATALOGUE. 423 



Page 168. Simsia^ canescens, Gray. PI. Fendl. 85. Stem leafy below 

 or at the base only, the long branches nearly naked ; leaves nearly sessile, 

 obovate or somewhat rhomboid, nearly entire, scabrous-canescent on both 

 sides; heads on long peduncles; involucre 4-6" wide, of few herbaceous 

 linear scales, densely covered with long white hairs ; rays very large, wedge- 

 obovate, obscurely 3-lobed at the apex, the tube long and slender ; achenia 

 oblong-wedge-shaped, villous with silvery-white hairs, especially along the 

 edges, and bearing 2 linear-subulate villous awns nearly as long as the disk- 

 corollas. — California and Arizona. Three other Helianthoid plants occur in 

 Dr. Palmer's collection. One of them, having the achenia destitute of pappus, 

 and with opposite linear revolutely margined leaves, is possibly a Heliomeris. 

 Another, not in flower, is perhaps an Encelia. The lower leaves are opposite, 

 petioled, oblong-lanceolate, 3 -nerved, obscurely toothed, and scabrous-canes- 

 cent on both sides. The third seems to be an undescribed Tithonia. 



TiTHONiA^ AEGOPHYLLA. Silvery-white with a velvety pubescence; 

 radical leaves 2-3' long, 1' broad, softly coriaceous, rhomboid-obovate, entire, 

 3 -nerved, narrowed into a petiole nearly as long as the leaf, (stem-leaves hot 

 seen;) heads more than 1' broad; involucral scales rigid, imbricated in many 

 rows, at length reflexed ; receptacle flattened-hemispherical ; chaif with sca- 

 rious margins, conduplicate and partly inclosing the compressed oblong- 

 wedge-shaped silky-villous achenia ; pappus of 2 short smooth rather stout 

 awns, and an intermediate very short lacerate-fringed membrane. — Only a 

 tuft of radical leaves and a single head have been examined. Dr. Palmer de- 

 scribes the stem as erect, 2-3° high, leafy, with the cauline leaves similar to 

 the radical ones. The plant seems to be as near to Viguiera as to Tithonia^ 

 and indeed the information comes from Dr. Gray that the two genera are to 

 be united by Mr. Bentham in his revision of the Compositce for the Genera 

 Plantarum. 



' SIMSIA, Pbes. A genus very near to Helianllms, but ■witli the involucre not imteicated, and the 

 pappus consisting only of 3 rather stout awns, -which, however, are wanting in one species of the genus. 



^TITHONIA, Desf. Heads many-flowered, radiate ; the rays ligulate, neutral ; disk-flowers per- 

 fect, the corolla 5-cleft, the tube rather short, inflated above. Involucre imbricated; the scales ovate, 

 rigid, with obtuse leafy appendages. Receptacle convex, the chaff lanceolate, membranaceous, and more 

 or less embracing the aohenium. Branches of the style with exserted hispid subulate appendages. Ache- 

 nia of the ray triangular or obcompreseed, pappus scan ty, very short, of the disk compressed or sub- 

 tetragonal, smooth or hairy, crowned with 1-2 awns from the stronger angles, at least in the central 

 flowers, and bearing a single series of minute denticulate squamellfe, (which in the species above de- 

 scribed are united into a ciliate crown.) — ^American herbs, with opposite or alternate triplinerved leaves 

 and yellow flowers. (Character mostly from De Candolle.) 



