CAEDUACEAE 



1285 



3-5-ribbed thick blades, narrowed into petiole-like bases, upper cauline leaves rather 

 remote, much reduced : heads long-peduncled, many-flowered : involucre 7-10 mm. high ; 

 bracts nearly oblong, or oblong-lanceolate, acute : corolla-tube about 10 mm. long, the 

 upper third dilated into a throat : achenes 3.5-5 mm. long : pappus-scales about as long 

 as the achene, entire. 



In moist soil, in the mountains, Pennsylvania to West Virginia and North Carolina. Summer. 



9. Marshallia trinervia (Walt.) Porter. Stem 3-7 dm. tall, usually simple: leaves 

 few, the basal and lower cauline 5-12 cm. long with mainly spatulate or oblanceolate thin 

 3-ribbed blades, the upper cauline slightly smaller than the lower, elliptic, ovate or ovate- 

 lanceolate, distinctly 3-ribbed : heads long-peduncled, many-flowered : involucre about 1 

 cm. high ; bracts linear-lanceolate, decidedly acute : corolla-tube 7-8 mm. long, the upper 

 third or fourth dilated into a throat : achenes 2-2.5 mm. long : pappus fully | as long as 

 the achene, entire. 



In dry or moist soil, Virginia to Tennessee, Alabama and Mississippi. Spring and summer. 



112. GALINSOGA E. & P. 



Annual caulescent herbs. Leaves opposite : blades simple, toothed. Heads radiate, 

 inconspicuous. Involucres campanulate or hemispheric : bracts imbricated in two series, 

 thin, the inner sometimes longer than the outer. Eeceptacle conic, or somewhat elongated, 

 chaffy. Eay-flowers 4-5, pistillate, fruit-producing : ligules white, very short. Disk-flow- 

 ers perfect, fruit-producing : corollas yellow. Anthers sagittate at the base. Stigmas 

 with acute appendages. Achenes broadened upward, 4^5-angled, or the outer ones slightly 

 flattened. Pappus various ; that of the ray of several bristles, or wanting ; that of the 

 disk of several lacerate or fimbriate scales. 



1. Galinsoga parviflora Cav. Foliage hispidulous or glabrate. Stems 1-7 dm. tall, 

 succulent, often branched : leaf-blades ovate to ovate-lanceolate, 2-5 cm. long, acute, ser- 

 rate-dentate or undulate, petioled : heads inconspicuous : involucres campanulate, 2-2.5 

 mm. high; bracts ovate, ciliate : ray-flowers few; ligules white, 1-1.5 mm. long, the 

 segments ovate : achenes cuneate, barely 2 mm. long, the inner ones with 8-15 pappus scales. 



In waste places, Massachusetts to Oregon, Georgia and Mexico. Naturalized from South America. 



113. TRIDAX L. 



Perennial caulescent herbs, usually branched at the base. Leaves opposite : blades 

 incised-toothed or pinnately dissected into narrow segments. Heads heterogamous, long- 

 peduncled, radiate. Involucre ovoid to campanulate : bracts in few series. Eeceptacle 

 flat or somewhat convex, chaffy. Eay-flowers pistillate, fruit-producing. Disk-flowers 

 perfect, fruit-producing. Anthers auricled-sagittate at the base. Stigmas of the perfect 

 flowers pubescent at the apex and with subulate appendages. Achenes broadened up- 

 ward, usually pubescent. Pappus of numerous aristate-acuminate plumose-ciliate scales. 



1. Tridax prociimbens L. Stem branched at the base, the branches spreading or 

 decumbent, more or less hirsute : leaf-blades ovate in outline, 2-5 cm. long, acute, incised 

 or incised-lobed, copiously pubescent, cuneate at the base : peduncles mostly 2-3 dm. long : 

 involucres solitary, 5-7 mm. high : bracts hispidulous, the outer lanceolate, acuminate, 

 the inner broadly oblong or oblong-obovate, mucronate : disk almost 1 cm. broad at matu- 

 rity : achenes silky, 2 mm. long. 



In sand or coral rock, Florida Keys. Native of tropical America. 



114. CLAPPIA A. Gray. 



Perennial shrubby but fleshy plants. Leaves alternate : blades entire or pinnately 

 3-5-parted. Heads radiate, peduncled. Involucres hemispheric : bracts leathery, imbri- 

 cated in 2-3 series, broad, obtuse. Eeceptacle convex, bristly-fimbrillate. Eay-flowers 

 12-15, pistillate, fruit-producing : ligules narrow, yellow. Disk-flowers perfect, fruit-pro- 

 ducing. Anthers entire at the base. Stigmas of the disk with triangular appendages. 

 Achenes narrow, terete, 8-10-nerved, hairy on the nerves. Pappus of 20-25 scale-like his- 

 pidulous bristles longer than the achene. 



1. Clappia suaedaef olia A. Gray. Shrubby, glabrous. Stems 2-4 dm. tall, widely 

 branched : leaf-blades linear, terete, 1-1.5 cm. long, entire or the lower ones pinnately 

 3-5-parted, sessile : heads solitary : involucre 6-8 mm. high ; bracts narrow, soon reflexed : 



