5' I 



I i iMl'OSITAE. 



Vol. 111. 



i. Thymophylla aurea (A. Gray) Greene. 

 Thyme-leaf. Fig. 4550. 



Lowellia aurea A. Gray, Mem. Am. Acad. (II) 4: 91. 



1849. 

 Hymenaherum aureum A. Gray, Proc. Am. Acad. 19: 



A-. 1883. 

 T. aurea Greene; Britt. & Brown, 111. Fl. 3: 453. 1898. 



Annual, glabrous, 4'-i2' high, much branched; the 

 leaves and involucre with large oval oil-glands. Leaves 

 alternate, or the lower opposite, sessile or nearly so, 

 very deeply parted into 5-9 linear-filiform, mostly 

 entire, blunt segments ; heads numerous, corymbose, 

 6"-io" broad, terminating the branches; involucre 

 about 3" high, its bracts acute; rays about 12, 2V-3" 

 long ; pappus of 6-8 erose truncate scales, somewhat 

 longer than the thickness of the achene. 



Kansas and Colorado to Texas and New Mexico. 

 June-Sept. 



88. PECTIS L. Syst. Nat. Ed. 10. 1221. 

 1759- 



Annual or perennial, diffuse prostrate or erect, mostly glabrous herbs, gland-dotted and 

 strong-scented, with opposite narrow sometimes ciliate leaves, and small usually cymose 

 heads of both tubular and radiate yellow flowers. Involucre cylindric, oblong or campanu- 

 late, its bracts in 1 series, narrow, keeled, distinct. Receptacle small, naked. Ray-flowers 

 pistillate, the rays small, entire or 3-lobed. Disk-flowers perfect, their corollas with expanded, 

 somewhat irregularly 5-cleft limbs. Anthers entire at the base. Style-branches of the disk- 

 flowers very short, obtuse. Achenes linear, slightly angled, striate. Pappus of several or 

 numerous scales, slender bristles or awns, sometimes with a few outer smaller additional 

 ones. [Latin, pecten, comb, referring to the pappus.] 



About 75 species, natives of the warmer parts of America. Besides the following, about 10 

 others occur in the southern and western parts of the United States. Type species : Pedis ciliaris L. 



i. Pectis angustifolia Torr. Lemon-scented 

 Pectis. Fig. 4551. 



Pedis angustifolia Torr. Ann. Lye. N. Y. 2: 514. 1827. 



Annual, much branched, 4-12' high, the branches 

 diffuse or ascending. Leaves narrowly linear, sessile, 

 obtusish, -2' long, 1" wide or less, often ciliate with 

 a few bristles near the base ; heads several or numer- 

 ous, short-peduncled, about 3" broad ; involucre short- 

 cylindric or narrowly campanulate, its bracts about 8, 

 linear, acutish, partly enclosing the outer achenes; rays 

 few, 3-toothed. or entire; pappus a crown of 4-6 some- 

 what united short scales, with or without 2 slender 

 short awns. 



In dry soil, Nebraska and Colorado to Mexico and Ari- 

 zona. Plant with the odor of lemons. May-Oct. 



89. ACHILLEA [Vaill.] L. Sp. PI. 898. 1753. 

 Herbs, mostly perennial, with erect leafy stems, finely 

 dissected, pinnatifid or serrate alternate leaves, and small 

 heads of both tubular and radiate flowers, corymbose at 

 the ends of the stem and branches. Involucre obovoid, or campanulate. its bracts appressed. 

 imbricated in few series, the outer shorter. Receptacle nearly flat or convex, chaffy, the mem- 

 branous chaff subtending the disk-flowers. Ray-flowers pistillate, fertile, the rays white or 

 pink. Disk-flowers perfect, fertile, their corollas yellow, 5-lobed. Anthers obtuse and entire 

 at the base. Style-branches of the disk-flowers truncate. Achenes oblong or obovate, slightly 

 compressed. Pappus none. [Named for Achilles.] 



About 75 species, natives of the northern hemisphere, mostly of the Old World. Besides the 

 following, another, or perhaps 2 others, occur in northwestern North America. Type species : 

 Achillea santolina L. 



Involucre broadly campanulate; leaves serrate. i. A. Ptarmica. 

 Involucre ovoid to cylindric ; leaves finely dissected. 

 Involucral bracts greenish-yellow; rays small. 



Plant loosely woolly or nearly glabrous; inflorescence flat-topped. 2. 



Plant densely woolly ; inflorescence convex. 3. 



Involucral bracts black-margined ; rays large. 4. 



A. Millefolium. 

 A. lanulosa. 

 A. borealis. 



