186 NORTH AMERICAN FLORA [VOLUME 34 
long as the turbinate throat; lobes deltoid; achenes 5—7 mm. long, hispidulous; pappus straw- 
colored, 5-6 mm. long; bristles hispidulous. (P?. Holwayanum is a luxuriant form with longer 
involucre, larger leaves, and sometimes 8-12 glands on each leaf-margin.) 
TypE LocaLity: Mountains near Lake Chapala, Michoacan. 
DISTRIBUTION: Michoacan, Guerrero, Oaxaca, and Jalisco. 
9. Porophyllum nummularium DC. Prodr. 5: 649. 1836. 
A shrub, with long terete glabrous brownish branches; leaves mostly opposite; petioles 
about 1 em. long; blades oval or rarely broadly elliptic, 1.5-3.5 cm. long, 1-2 em. wide, sinu- 
ate, not very thin, glabrous; glands elliptic, 3-5 along each margin, one at the apex and a few 
scattered over the surface; heads cymose, with the peduncles more or less spreading in age; 
involucre at first cylindric, 10-14 mm. high; bracts linear, acute, with two rows of glands; 
corollas cream-colored, about 1 cm. long; tube slender, pubescent, several times as long as 
the funnelform throat; lobes linear-lanceolate, puberulent; achenes 6 mm. long, hispidulous; 
pappus straw-colored, 7 mm. long; bristles hispidulous. 
TYPE LocaLity: Tehuantepec, Oaxaca. 
DISTRIBUTION: Michoacan to Yucatan and Guatemala. 
10. Porophyllum oblongum Rydberg, sp. nov. 
A shrub, with slender, terete, striate, brownish branches; leaves mostly opposite; petioles 
slender, 1-1.5 cm. long; blades oblong or rarely elliptic, 2-4 cm. long, 0.5-1.5 em. wide, very 
thin, sinuate-undulate, with 3-6 marginal glands on each side, 1 terminal one, and a few scat- 
tered over the surface; heads cymose; peduncles more or less spreading, 2—4 cm. long; invo- 
lucre 12-13 mm. high, cylindric, pale; bracts mostly 5, linear, acute, with 2 rows of linear 
glands; corollas almost white, about 1 cm. long; tube slender, puberulent, much longer than 
the funnelform throat; achenes pale, 6 mm. long, hairy; pappus straw-colored, 7 mm. long; 
bristles scabrous. 
Type collected at Culiacan, 1891, Palmer 1807 (herb. N. Y. Bot. Gard.). 
DISTRIBUTION: Sinaloa. 
11. Porophyllum Ervendbergii A. Gray, Proc. Am. Acad. 19: 35. 
1883. 
- A slender shrub, 5 dm. high or more, with terete, brown branches; leaves opposite; petioles 
slender, about 1 cm. long; blades elliptic, 2-3 cm. long, obtuse at the apex, acute at the base, 
sinuate, with 2-4 marginal glands on each side, 1 terminal one, and a few scattered over the sur- 
face; heads cymose, erect, 10—-15-flowered; peduncles 2-3 cm. long, ascending-spreading; 
involucre cylindric, 11-12 mm. high, 3 mm. broad; bracts 5, narrowly linear, acuminate; glands 
few, linear, in 2 irregular rows; corollas pale with dark streaks, puberulent, 8 mm. long; tube 
much longer than the funnelform throat; achenes 6.5 mm. long, hispidulous; pappus tawny, 
6 mm. long; bristles hirsutulous. 
TYPE LocALity: Wartenberg, Tamaulipas. 
DISTRIBUTION: Tamaulipas; Yucatan (?). 
12. Porophyllum divaricatum Rydberg, sp. nov. 
A divaricately branched shrub, with terete, glabrous, brown branches; leaves opposite; 
petioles about 5 mm. long; blades rather thick, 1—2 cm. long, elliptic or rarely oval, glabrous, 
obtuse at the apex, abruptly acute at the base, with 1 or 2 glands along each margin and a 
single one at the apex; heads cymose-corymbose; peduncles spreading, 1-3 cm. long; involucre 
cylindric-campanulate, about 1 cm. high; bracts 5, linear, acute, greenish, with 2 rows of 
linear glands; corollas nearly white with darker veins, 9 mm. long; tube slender, puberulent, 
several times as long as the narrowly funnelform throat; achenes 6 mm. long, hispidulous; 
pappus 6-7 mm. long, straw-colored or at first tinged with pink; bristles scabrous. 
Type collected near Mazatlan, Sinaloa, 1899, Goldman 386 (herb. N. Y. Bot. Gard.). 
DISTRIBUTION: Sinaloa to Vera Cruz (?). 
