244 ELEMENTS OF BOTANY. 



2. C. LANCEOLATA L. TiCKSEED. Perennial; stem slender, 

 erect or ascending, smooth or slightly pubescent below, simple, 9-15 

 in. high; leaves opposite, the lower spatulate to elliptical, some- 

 times lobed, on long, ciliate petioles, the upper lanceolate, sessile; 

 heads few, on long peduncles ; bracts ovate-lanceolate, the outer 

 narrower; ray flowers 6-10, rays 3-5-lobed, bright yellow; achenes 

 oval, broadly winged, warty; pappus of 2 teeth. May-June. On 

 rich, dry soil. 



3. C. AURicuLATA L. RUNNING TiCKSEED. Perennial; stem 

 ascending or decumbent, weak, smooth, nearly simple, 6-1.5 in. long; 

 leaves ovate to oval, entire or with 2-4 small and rounded lobes at 

 the base, pubescent, long-petioled ; heads l-lg- in. wide, few or sin- 

 gle; outer bracts narrower than the inner; rays 6-10, mostly 

 4-toothed at the apex ; chaff as long as the flowers ; achenes oblong, 

 the wings narrow and thickened ; pappus of 2 minute teeth. April- 

 May. In rich woods. 



XII. BIDENS. 



Annual or" perennial ; leaves opposite, simple or pinnately 

 divided ; heads radiate or discoid, corymbed ; bracts in 2 

 series, the outer often long and leaf-like ; receptacle chaffy ; . 

 ray flowers neutral or wanting, disk flowers perfect ; achenes 

 fiat or 4-angled ; pappus of 2-4 downwardly barbed bristles. 



1. B. FRONDOSA L. Beggar Ticks. Annual ; stem erect, smooth 

 or slightly pubescent, usually purple, branched, 2-5 ft. high ; leaves 

 pinnately 3-5-divided, the segments lanceolate to oval, acuminate, 

 sharply serrate, thin; heads discoid, long-peduncled ; outer bracts 

 leaf-like ; achenes flat, narrowl}^ wedge-shaped, ciliate on the edges ; 

 pappus of 2 awns. June-September. A common weed. 



2. B. HiPixNATA L. Spanish Needles. Annual; stem erect, 

 slender, smooth, 4-angled, branched, 2-5 ft. high ; leaves bipinnate, 

 the segments small, ovate to lanceolate, acute, serrate ; heads small, 

 radiate ; bracts narrow, nearly equal ; ray flowers 2-4, yellow, short ; 

 achenes linear, 4-angied, slightly pubescent; pappus of 4 barbed 

 awns. July-September. A common weed. 



XIII. HELENIUM. 



Annual or perennial; leaves alternate, decurrent on the 

 stem; heads radiate, peduncled, many-flowered; bracts in 2 

 series, the outer linear and spreading, the inner few and 

 scale-like; receptacle naked, convex or oblong; ray flowers 



