144 FIELD COLUMBIAN MUSEUM BOTANY, VOL. III. 



diffuse branches and small leaves; heads scattered and solitary in the axils, 

 on capillary 3-4 bracteate peduncles 2~j cm. long; involucre pale, 4 mm. 

 high; pappus hardly equaling the achene." 



Hab. Sercania near Maxcanii, Sept. 14, 1866, Schott 666 (type). 



Pectis linifolia* L. Syst. Nat., Ed. 10:1221. 



A slender, erect, branching herb, with smooth, angled stem, and 

 branches, and opposite, sessile, linear-lanceolate, entire leaves, one or 



two pairs of bristles at the base, 

 the leaves dotted with oval oil 

 glands. Inflorescence loosely 

 cymose-paniculate, branchlets di- 

 varicate, peduncles bracteolate, 

 clavate at the summit. Heads 

 7-8 mm. high, 2. mm. broad, ray 

 flowers 4 or 5, disk flowers 2-4. 

 Involucre cylindrical, bracts 5, 

 becoming involute, oblong, ob- 

 tuse, a row of oil glands afong 

 the margins. Ray corollas 

 purplish white, ligule ovate, en- 

 tire, i mm. long, spreading or 

 erect; disk corollas dark pur- 

 ple, 5 lobed. Receptacle con- 

 vex. Achene black, linear-oblanceolate, .5x4 mm.; in section 

 concavo-convex, the angles rounded; papillate striate, a few short 

 thickened hairs at the summit, otherwise glabrous; pappus of 2 stiff, 

 divergent, slender, smooth awns, 1.6 mm. long. 



Hab. "Herb, 3 feet high, common along the Chique road near 

 Izamal," Sept. Gaumer 887 {Pectis punctata Jacq. Field Col. Mus. 

 Bot. 1:325), "on stone walls, Izamal," p/p. 



Yucatan specimens differ from those of this species from the West 

 Indies in having slightly shorter heads, achenes 2 awned (while West 

 Indian plants examined have 3-awned achenes) with hairs only at the 

 summit. 



ACHILLEA L. Sp. PL, 898. 



Heads heterogamous, radiate; rays pistillate, fertile, ligulate; disk 

 flowers perfect, fertile, tubular. Involucre ovoid or campanulate, its 

 bracts appressed, imbricated in few series, the outer shorter. Recep- 

 tacle convex or nearly plane, chaffy; scales membranaceous, subtend- 

 ing the disk flowers. Achene dorsally compressed with a narrow 

 cartilaginous margin; pappus none. Perennial, strong-scented herbs 

 with small, corymbose heads. 



* There has been much confusion concerning the species named P. linifolia by Linnaeus. The 

 above nomenclature is given on the authority of M. L. Fernald in his "Systematic Study of the 

 United States and Mexican Species of Pectis '' Proc. Am. Acad. Sci. 33:57-86. 



