Part 1, 1914] CARDUACEAE: HELENIEAE 7 



1. Psilostrophe gnaphalodes DC. Prodr. 7: 261. 1838. 



Riddellia arachnoidea A. Gray, Mem. Am. Acad. II. 4: 94. 1849. 

 Riddellia gnaphalioides O. Hoffm. Bull. Herb. Boiss. 3: 628. 1895. 



A biennial with a taproot; stem sparingly branched, 3-5 dm. high, loosely villous; basal 



leaves rather many, oblanceolate or linear-oblanceolate, 5-8 cm. long, loosely long-villous, 



rarely lobed; stem-leaves oblong or linear, sessile; heads in congested corymbs, short-peduncled; 



involucre densely woolly, 6 mm. high and 3 mm. broad; ligules 3-4, bright-yellow, about 6 mm. 



long, 3-clef t about three fourths their length ; disk-flowers 8-12; achenes long-villous ; squamellae 



of the pappus lanceolate, acute. 



Type locality: San Luis Potosi. 



Distribution: Texas to San Luis Potosi and Zacatecas. 



2. Psilostrophe villosa Rydb.; Britton, Man. 1006. 1901. 



Psilostrophe cerifera A. Nelson, Proc. Biol. Soc. Wash. 16: 21. 1903. 

 Psilostrophe cerifera biennis A. Nelson, Proc. Biol. Soc. Wash. 16: 21. 1903. 

 Psilostrophe biennis Hay, Miller & White, Proc. Biol. Soc. Wash. 16: 186. 1903. 



A biennial or short-lived perennial, scarcely woody at the base; stem 2-4 dm. high, 

 loosely woolly, corymbosely branched; lower leaves oblanceolate, entire, or some pinnately 

 3-5-lobed, 2-10 cm. long, short-petioled, loosely villous, the upper ones smaller and sessile; 

 heads several, corymbosely clustered; involucre about 5 mm. high, 3 mm. broad; ligules 3-4, 

 light- yellow, turning darker or buff, 3-4 mm. long, 3-clef t about one third their length; disk- 

 corollas 5-8, more or less ceriferous; achenes glabrous, linear; squamellae lanceolate, about 

 half to two thirds as long as the disk-corollas. 



Type locality: Kansas. 



Distribution: Kansas to Texas and eastern New Mexico. 



Illustrations: Britt. & Brown, 111. Fl./. 3958 (as P. Tagetinae); ed. 2./. 4527. 



3. Psilostrophe Tagetinae (Nutt.) Britt. & Brown, 111. Fl. 3: 



444. 1898. 



Riddellia Tagetinae Nutt. Trans. Am. Phil. Soc. II. 7: 371. 1841. 

 Riddellia tagetina T. & G. Fl. N. Am. 2: 362. 1842. 

 Psilostrophe tagetina Greene, Pittonia 2: 176. 1891. 



A perennial with a thick taproot; stems 2-3 dm. (rarely 4 dm.) high, woody at the base, 

 loosely white- villous, much branched; lower leaves spatulate, 2-5 cm. long, densely villous; 

 upper leaves linear or linear-oblanceolate, greener; heads in rather open corymbs, short-pe- 

 duncled; involucre about 6 mm. high, 3 mm. broad; ligules 3-5, bright-yellow, 5-7 mm. long, 

 3-lobed about one fourth their length; disk-flowers 7-10; achenes glabrous; squamellae lance- 

 olate, acute, from one half to two thirds as long as the disk-corollas. 



Type locality: Southern range of the Rocky Mountains toward the sources of the Platte 

 [Colorado]. 



Distribution: From western Texas to Colorado, Arizona, and Chihuahua. 

 Illustration: Emory, Notes Mil. Recon. Bot. pi. 5. 



4. Psilostrophe sparsiflora (A. Gray) A. Nelson, Proc. Biol. Soc. 

 Wash. 16: 23. 1903. 



Riddellia tagetina sparsiflora A. Gray, Syn. Fl. N. Am. I 2 : 318. 1886. 

 Psilostrophe tagetina sparsiflora Greene, Pittonia 2: 176. 1891. 



A perennial with thick taproot and woody caudex; stems usually several, 2-4 dm. high, 



angled and striate, sparingly pilose and glandular-granuliferous, sparingly branched; branches 



strongly ascending; basal leaves spatulate, 5-8 cm. long, loosely villous; upper leaves linear or 



linear-oblanceolate; heads comparatively few; involucre about 5 mm. high, 3 mm. broad, 



villous; ligules usually 3, bright-yellow, 6-8 mm. long, shallowly 3-lobed; disk-corollas about 



10, glabrous; achenes angled, glabrous; squamellae unequal, lanceolate, scarcely half as long 



as the disk-corollas. 



Type locality: Southern Utah. 

 Distribution: Southern Utah and Arizona. 



