440 



THE KINDS OF PLANTS 



V 



20. BIDENS. Bur-marigold. Beggar's Ticks. Pitchforks. 



Annual or perennial, similar to Coreopsis, including weeds known as 

 Spanish-needles or stick-tights: leaves opposite: flowers mostly yellow; 

 involucre double, outer scales large and leaf-like; heads many -flowered ; 

 ray flowers 4-8, neutral, or none; disk flowers perfect, tubular: achenes 

 flattened or slender and 4-angled, crowned with 2 or more rigid downwardly 

 barbed awns. 



B. frondosa, Linn. Figs. 418, 558. 



Smooth or sparsely hairy, 2-6 ft. tall, 



branching: leaves 3-5-divided, or 



upper simple; leaflets stalked, lanceo- 



'■ ' ,'r"> late, serrate: outer involucre longer 



^ '^O than head; bracts foliaceous: achenes 



\t wedge-ovate, flat, 2-awned. In moist 



places. Annual. 



B. lsevis, BSP. Smooth branching 

 annual, 6 in. to 2 ft., usually abundant along 

 ditches: leaves sessile, simple, lanceolate, acumi- 

 nate, serrate, the bases sometimes united: outer 

 involucral bracts exceeding the inner, but shorter 

 than the yellow, oval or oblong rays: rays about 1 

 in. long, 8 or 10 in number: achenes small, wedge- 

 shaped, truncate, prickly on margins, with 2 rigid 

 downwardly barbed awns. 



B. bipinnata, Linn. Spanish needles. Annual: 

 stem quadrangular, erect, branching freely: leaves 

 1-3 times pinnate, leaflets lanceolate, pinnatifid: 

 heads small on slender peduncles; rays short, pale 

 yellow, 3, 4 or more: achenes smooth, 3-4-grooved, 

 2- or 6-awned (awns barbed). 



21. COREOPSIS. Tickseed. 



Low herbs with opposite, sometimes alternate leaves: 

 heads of tubular and ray flowers solitary, or corymbed on 

 long peduncles; involucre double, bracts all united at 

 base, the 8 outer ones usually leafy; the inner erect; re- 

 ceptacle chaffy; ray flowers neutral, usually yellow; disk 

 flowers tubular, perfect, yellow or purple; pappus of 2 short teeth or a 

 crown-like border, or none: achenes flat, often winged, 2-toothed or 2- 

 armed. A number of rather showy but somewhat weedy plants. 



C. tinctoria, Nutt. Calliopsis. Annual or biennial, glabrous, erect, 1-3 

 ft. : disk flowers dark purple ; ray flowers about 8, yellow with purple bases, 

 the edges coarsely 3-toothed: leaves alternate, 2 or 3 times pinnately- 

 divided; the lower petioled, the upper sessile and often entire: heads 1-1 J^ 

 in. wide, on slender peduncles. A favorite in gardens. Ray flowers variable 

 in shape and coloring. 



C. tripteris, Linn. Tall coreopsis. Tall and leafy stems, 4-9 ft. : disk and 



