APRIL, 1904. PLANTS YUCATAN^; MILLSPAUGH & CHASE. 125 



cated in 2-3 series. Receptacle convex, chaffy; scales concave, 

 enfolding or clasping the achenes, deciduous. Achene laterally flat- 

 tened, margins thin, not winged; pappus (in our species) of 2 rigid 

 awns. Herbs, or shrubby, with rather showy heads of yellow flowers. 



Encelia Chaseae Millsp. sp. nov.* 



An erect, branching herb, with terete, striate, hispid stem, and 

 branches, and alternate, deltoid-ovate (or upper lanceolate) acuminate, 

 dentate, hispidulous leaves, abruptly tapering into a short, usually 

 wingless (never auricled) petiole or the upper sessile. Inflorescence 

 of solitary heads, terminal and axillary; peduncles striate, glandular, 

 hispid, with spreading white hairs. Heads 12-14 mm - high, 2.4 cm. 

 broad (when rays are present), ray flowers 8-10 or wanting, disk flow- 

 ers numerous. Involucre wide-campanulate, bracts erect, subrigid, in 

 2 series, glandular-hispid, the outer shorter, lanceolate, acuminate, 

 inner striate, long acuminate. Ray corollas yellow, ligule elliptic, 

 bidentate, 4-7 mm. long, spreading; disk corollas 

 cylindrical, inflated below, 5 lobed. Receptacle 

 slightly convex; scales broad, conduplicate, erose- 

 denticulate, mucronate, hispidulous on the keel, 

 loosely enfolding the achenes and deciduous with 

 them. Achene slatey brown, often mottled with a 

 darker shade, 3.6-4x6-6.5 mm.; in section subcon- 

 cavo-convex; obovate, subcordate at the summit, 

 laterally much compressed, with a thin, ciliate margin, 

 appressed pilose or the outermost nearly glabrate ; awns 

 usually unequal, denticulate-ciliate, .7-2.2 mm. long. 

 Hab. : Ruins of Kobah, Nov. 26, 1865, Schottyii; 

 "herb, 5 feet high, common at Izamal, Oct." Gaumer 

 910, Chichankanab 2045, San Anselmo 204.6. 



Our specimens differ from E. Mexicana in having 

 leaves never lobed, on petioles never auricled ; heads larger, rays much 

 smaller, paler, often none; achenes nearly a third larger, but in color, 

 shape, pubescence and awns very similar to E. Mexicana. No. 4602 

 Pringle Tequila, Jalisco, referred to by Robinson and Greenman (Proc. 

 Am. Acad. 29:388) under Encelia Mexicana Mart, closely approaches 

 our Yucatan specimens and has achenes intermediate between those 

 of our specimens and those of Mexicana. Concerning Pringle 4602 

 Robinson and Greenman add: "While different forms of this species 

 certainly show striking differences in the features mentioned (unlobed 

 leaves, petioles not auricled, larger heads, and elongated involucra.1 

 bracts) a series of specimens show that these' characters vary quite 

 independently of each other, forming various combinations, so that 

 varieties based upon them could have little more than formal value." 



PLAGIOLOPHUS Greenman gen. nov. 



"(Verbesinae.) Heads homogamous, several flowered. Involucral 

 bracts 2-3 seriate, the outer series longer, foliaceous, and spreading. 



a *For Mrs. Agnes Chase, whose careful drawings illustrate this publication. 



