CARDUACEAE. 197 



34. POLYPTERIS Nutt. Perennial tall branching herbs. Leaves alter- 

 nate, or opposite on the lower part of the stem: blades entire, thick. Heads 

 corymbose, scattered, discoid. Involucre turbinate: bracts rather numerous 

 and broad, searious above the base, mainly in 2 series. Receptacle naked. 

 Ray-flowers wanting. Disk-corollas white or pink, with a campanulate throat 

 and a longer slender tube. Anthers longer than the filaments. Achenes 4- 

 angled, narrow, pubescent. Pappus of several slender pubescent scales. 



1. P. integrifolia Nutt. Plants 1.5 m. tall or less, corymbose above: leaf- 

 blades lanceolate or linear-lanceolate to linear, 3-7 cm. long, obtuse or acutish: 

 involucre corolloid ; bracts oblong or spatulate, 10-14 mm. long, obtuse : 

 corollas 9-14 mm. long; lobes linear-lanceolate: achenes narrowly obpyramidal, 

 4-5 nun. long. — Pinelands. 



35. PAJLATOXIA Lag. Annual or perennial, sometimes partially woody 

 plants. Leaves alternate or opposite: blades narrow, entire. Heads corym- 

 bose. Involucre campanulate to oblong: bracts narrow, herbaceous. Disk- 

 corollas with a cylindric throat much longer than the tube. Anther-appendages 

 lanceolate. Pappus of 4-8 scales. 



1. P. Feayi A. Gray. Stems 6-15 dm. tall, minutely pubescent: leaf -blades 

 oblong to oblong-lanceolate, 2-7 cm. long: involucres 7-8 mm. long; bracts 

 obtuse: corollas 7-8 mm. long: achenes 5-6 mm. long. — Pinelands. 



36. FLAVERIA Juss. Low branched or diffuse herbs or partially woody 

 plants. Leaves opposite: blades entire or toothed. Heads small, radiate or 

 discoid, usually clustered. Involucres narrow, 1-several-flowered : bracts few, 

 often 2-5, equal or nearly so. Receptacle naked. Ray-flowers usually solitary, 

 pistillate, fruit-producing, the ligules yellow, or wanting. Disk-flowers 1-15, 

 perfect, fruit-producing: corollas yellow or yellowish, with a short throat and 

 a longer tube: lobes deltoid or triangular. Filaments mostly shorter than the 

 anthers. Achenes narrow, 8-10-ribbed. Pappus wanting. 



1. F. linearis Lag. Stem 2-9 dm. long, the branches often decumbent, corym- 

 bose above: leaf-blades narrowly linear to narrowly linear-lanceolate, 3-10 

 cm. long, entire: heads numerous: involucres about 4 mm. high; bracts mostly 

 5, oblong to lanceolate: ligules 2-3.5 mm. long: achenes about 1.5 mm. long. 

 — Everglades, pinelands and coastal sand-dunes. — F. K. (Bah., Cuba, Ant.) 



37. HELENIUM L. Stout or stoutish, bitter herbs. Leaves alternate: 



blades entire, toothed, or pinnatifid, often decurrent. Heads scattered, but 



often numerous. Involucre flattish: bracts spreading or reflexed. Receptacle 



conic, oblong or subglobose. Ray-flowers several, the corollas with cuneate 



ligules. Disk-corollas with broadly ovate lobes, Achenes ribbed. Pappus of 



5-8 acuminate or awn-tipped scales, — Sneezeweed. 



Stem winged : leaves mostly cauline : disk-corollas 2-3 mm. long : pappus about 1 

 mm. long. 1- H- nudiflorum. 



Stems wingless: leaves mostly basal: disk-corollas 4-5 mm. long: 



pappus about 2 mm. long. 2. H. Hclcnium. 



1, H, nudiflorum Nutt. Plants 2-10 dm. tall, corymbosely branched above: 

 leaf-blades oblanceolate to oblong or linear, 2.5-12 cm. long, those of the 

 lower leaves often toothed: involucral bracts narrowly linear to linear-subu- 

 late, 5-7 mm. long: ligules 10-15 mm. long. — Pinelands. 



2, H, Helenium (Nutt.) Small. Plants 3-7 dm. tall, simple: leaf-blades 

 linear or nearly so, 5-15 cm. long, undulate or coarsely few-toothed: invo- 



