126 



FIELD COLUMBIAN MUSEUM BOTANY, VOL. III. 



Receptacle short, conical: Corollas equal, regular, with slender tube 

 ampliated above into a 5-toothed limb. Pappus of two unequal awns 

 and one or more intermediate laciniate scales. Anthers slightly sagit- 

 tate at the base, appendaged at tRe apex. Achenes obovate or oblong 

 cuneate, contracted above into a short outwardly curved neck, the 

 outer narrower, obtusely angled, and with a more or less reduced pap-^ 

 pus, the inner strongly compressed laterally and winged. Leaves 

 opposite. Heads of medium size, terminating the stems and branches 

 on rather long slender peduncles. Diffusely branched herbs, slightly 

 woody at the base, the affinity of which is with Wedelia and Zexmenia. 

 The generic name is taken from rr/ia^:? and A<ty>c in reference to the 

 peculiar oblique or slightly curved nature of the neck or constricted 

 portion of the achene." 



Plagiolophus Millspaughii Greenman sp. nov. 



Diffusely* branched from the base; stems about 4.5 dm. or more high, 

 hirsute pubescent; leaves ovate to ovate-acuminate, I to j.j" cm, long, about 

 one-half as broad, acute, narrowed at the base into a short petiole, subentire 

 or crenate- dentate ) j nerved, oppressed pubescent above, later becoming some- 

 what tuberculate-hispid, appressed canescent beneath; petioles j to 10 mm. 

 in length; heads erect or sometimes nodding 6-7 mm. high, I cm. or less in 

 diameter, about 40 flowered; involucral bracts appressed pubescent, the 

 outer narrowly oblong, obtuse, much exceeding the disk; inner ovate, 

 acute, ciliolate, erect; corolla white; receptacle short conoid some- 

 what lengthened at maturity ; palea 

 acute, pubescent at the summit; 

 the outer achenes slightly or not at all 

 winged, more or less obtusely angled 

 and hirtellous roughened, the inner 

 bearing a rather prominent cartilagi- 

 nous ciliated wing; the inner awn of 

 the pappus about twice as long as the 

 outer. Achenes heteromorphous, 

 brown, excluding wings and pappus 

 1-1. 2x2.1 mm. , cuneate ; in section 

 unsymmetrically biconvex; the 

 outer achenes less compressed than 

 the inner, wingless or nearly so, 

 corky-tuberculate roughened, hir- 

 tellous toward the summit, pappus 

 awns reduced to the length of the laciniate scales; inner achenes 

 showing gradation from characters given to nearly smooth achene with 

 wings .5-. 7 mm. wide, and unequal pappus awns 1-2 mm. long. 



Collected by Dr. G. F. Gaumer near Izamal, Yucatan, August to 

 September, 1895, No. 792, and at Buena Vista Xbac, April 1896, No. 

 1055; Sayi in cornfields, Mch. 4, 1903, Ccec. et Ed. Seler 3895. 



In general habit the above species bears a resemblance to Zexmenia 



*In italics are given Dr. Greenman's description and notes, additional descriptive matter and 

 notes are given in roman. The generic description is Dr. Greenman's. 



