1290 CAKDUACEAE 



1 or 2 series, nearly equal. Receptacle convex , naked. Ray-flowers pistillate, fruit-produc- 

 ing : ligules yellow, or rarely wanting. Disk-flowers perfect, fruit-producing : corollas with 



4 lobes. Anthers sagittate at the base. Stigmas of the disk-flowers with pubescent subu- 

 late appendages. Achenes flattened, with ciliate or cartilaginous margins. Pappus of 

 1 or 2 longer bristles often with small bristles between, or sometimes crown-like. 



1. Laphamia Lindheimeri A. Gray. Foliage finely but closely pubescent. Stems 

 1-3 dm. tall, corymbosely branched : leaf-blades ovate to oblong, 1-2 cm. long, glabrate, 

 acute, entire or shallowly serrate, cuneate or truncate at the base, petioled : heads about 



5 mm. high : involucres campanulate ; bracts linear or slightly enlarged upward : ray- 

 flowers 3-6 or wanting : pappus a slender bristle about as long as the corolla-tube. 



On rocky banks, Texas. 



124. HELENIUM L. 



Annual, biennial or perennial caulescent bitter herbs. Leaves alternate : blades entire 

 or toothed, often decurrent on the stem. Heads radiate or rarely discoid, peduncled. In- 

 volucres flattish : bracts narrow, in 1 or 2 series, spreading or reflexed. Receptacle con- 

 vex, oblong or subglobose, naked. Ray-flowers pistillate and fruit-producing, or neutral : 

 ligules yellow or brown at the base. Disk -flowers perfect, fruit-producing : corolla yellow, 

 purple or brown, with glandular lobes. Anthers 2-toothed or sagittate at the base. Stig- 

 mas of the disk flattened and truncate. Achenes broadened upward, truncate. Pappus of 

 5-8 entire, toothed or lacerate acuminate or awn-tipped scales. SNEEZEWEED. 



Ray-flowers pistillate. 



Plants annual or sometimes biennial. 



Leaf-blades narrowly linear or linear-filiform, not decurrent 



Disk yellow : leaves with entire blades. '1. H. tenuifolium. 



Disk purple-brown : some of the lower cauline leaves with pinnately 



parted blades. 2. H. badium. 



Leaf-blades broader, all or some of them conspicuously decurrent on the 



stem. 

 Disk oblong or ovoid. 



Receptacle conic or oblong-cylindric : disk becoming much longer 



than thick. 3. H. quadridentatum. 



Receptacle ovoid f disk but little longer than thick. 4. H. ooclinum. 



Disk globular. 



Mature disk 4-6 mm. in diameter. 



Receptacle depressed : pappus-scales shorter than the width of 



the achene. 5. H. elegans. 



Receptacle conic-ovoid : pappus-scales about % the length of the 



achene. 6. H. microcephalum. 



Mature disk 8-10 mm. in diameter. 7. //. amphibolum. 



Plants perennial. 



Receptacle ovoid or conic. 



Wings of the upper part of the stem and the branches 1 mm. wide or 



less : receptacle ovoid. 

 Receptacle 2.5-3.5 mm. high : ligules of the ray-flower 6-15 mm. long. 



Disk yellow. 8. //. parviflorum. 



Disk brown or purple. 9. H. nudiflorum. 



Receptacle 6-7 mm. high : ligules of the ray-flowers 25-30 mm. long. 10. H. campestrt. 

 Wings of the upper part of the stem and the branches over 2 mm. wide : 



receptacle conic. 11. H. polyphyttum. 



Receptacle hemispheric or depressed. 12. //. autumnale. 



Ray-flowers neutral. 



Receptacle ovoid or ovoid-conic : disk globular or globose-spheroidal. 



Disk about 1.5 cm. broad : ligules with slender, acute segments : pappus- 

 scales dissected to about the middle. 13. H. fimbriatum. 

 Disk about 2 cm. broad : ligules with broad, obtuse segments : pappus- 

 scales nearly entire. 14. H. Curtitii. 

 Receptacle flattish or depressed-hemispheric : disk similar. 

 Disk yellow. 



Leaf-blades entire or merely undulate. 15. H. Hdenium. 



Leaf-blades sinuate-dentate or pinnatifid. 



Achenes glabrous. 16. H. incisum. 



Achenes pubescent. 17. H. vernale. 



Disk purple or brown. 18. H. brevtfolium. 



1. Helenium tenuifolium Nutt. Annual, glabrous or sparingly pubescent above. 

 Stems 2-4 dm. tall, often branched into a bushy head : leaves numerous ; blades narrowly 

 linear, 1-5 cm. long, usually entire, not decurrent : heads showy : involucral bracts linear- 

 subulate, 4-6 mm. long, spreading or reflexed : ray-flowers few ; ligules yellow, 6-7 mm. 

 long, 3-4-toothed : disk yellow, 6-8 mm. broad : pappus-scales ovate, prolonged into slender 

 tips. 



In waste places and moist soil, Virginia and Missouri to Florida and Texas. Naturalized east- 

 ward. Summer and fall. 



