1432 CONTRIBUTIONS FROM THE NATIONAL HERBARIUM 



Petioles and leaves pubescent, not glaucescent 4. P. paltneri. 



Stem and branches densely pubescent. 



Heads 11-flowered; leaves rather densely pubescent over whole surface beneath. 



5. P. pubens. 



Heads 8-flowered; leaves sparsely short-pubescent beneath chiefly along the 



venation 6. P. sinaloae. 



1. Piptothrix goldmanii Robinson, Proc. Amer. Acad. 35: 328. 1900. 

 Known only from the type locality, near Batopilas, Chihuahua. 

 Suffrutescent (?); stem wine-color; leaf blades deltoid-ovate, 6 to 9 cm. long, 



4.5 to 7 cm. wide, acurtiinate, dentate-serrate, sparsely puberulous on the veins 

 beneath; panicles about 7 em. wide; heads 4 mm. high, about 24-flowered. 



2. Piptothrix aegiroides Robinson, Proc. Amer. Acad. 41: 273. 1905. 

 Known only from the type locality, mountains about Etzatldn, Jalisco, altitude 



1,830 meters. 



Herbaceous (?), 0.6 to 1.3 meters high; stem purplish; leaf blades triangular- 

 ovate, 5 to 7.5 cm. long, 2.5 to 5.8 cm. wide, acuminate, dentate-serrate, pubescent 

 with several-celled hairs on the veins beneath; heads 6 mm. high, 20-flowered. 



3. Piptothrix jaliscensis Robinson, Proc. Bost. Soc. Nat. Hist. 31: 268. 1904. 

 Known only from the type locality, mountains above Etzatldn, Jalisco, altitude 



1,830 meters. 



Suffrutescent (?), 0.6 to 1 meter high; stem glaucescent; leaf blades ovate, 

 3 to 5 cm. long, 1.8 to 4 cm. wide, acuminate, rounded or subcordate at base; 

 heads in close clusters, 6 mm. high. 



4. Piptothrix palmeri A. Gray, Proc. Amer. Acad. 21: 383. 1886. 

 Known only from the type locality, near Batopilas, Chihuahua. 

 Frutescent; leaf blades ovate, 3 to 5.5 cm. long, 1.3 to 2.8 cm. wide, acuminate, 



rounded or subcordate at base, puberulous beneath on the veins, as well as on 

 the petioles; panicles rounded, about 4 cm. wide; heads 5 mm. high, white or 

 "ochroleucous." 



5. Piptothrix pubens A. Gray in S. Wats. Proc. Amer. Acad. 22: 419. 1887. 

 Chihuahua and Jalisco; type from Rio Blanco, Jalisco. 



Frutescent, up to 2 meters high; stem and branches sordid-puberulous; leaf 

 blades ovate, 2 to 6.5 cm. long, 1 to 3.2 cm. wide; heads 3.5 to 5 mm. high. 



6. Piptothrix sinaloae Blake, Proc. Biol. Soc. Washington 32: 190. 1919. 

 Known only from the type- locality, Sierra del Mineral del Tominil, San 



Ignacio, Sinaloa, altitude 1,500 meters. 



Shrub 0.5 to 0.8 meters high; branches densely incurved-pubescent; leaf 

 blades ovate, 5 to 5.5 cm. long, 2 to 3.2 cm. wide, acuminate, serrate. 



16. EUPATORIUM L. Sp. PI. 836. 1753. 

 (Contributed by Dr. B. L. Robinson.) 



References: H. B. K. Nov. Gen. & Sp. 4: 104-134. 1820; DC. Prodr. 5: 

 141-186. 1836. 



Shrubs or small trees, or often herbs; leaves mostly opposite, filiform to orbic- 

 ular, membranaceous to coriaceous; heads homogamous, (1-mostly) 5 to 100- 

 flowered, usually in corymbose or thj'rsoid panicles; corollas red, purple, blue, 

 or white, rarely ochroleucous or greenish yellow; anthers appendaged at the 

 tip, entire at base; style branches long and at maturity much exserted, threadlike 

 or more often club-shaped, often colored; achenes columnar to obovoid, 5-ribbed 

 or 5-angled; pappus of many hairlike bristles, white, sordid, straw-colored, 

 roseate, purple, or tawny, usually subequal, occasionally the outermost much 

 shorter. 



