188 NORTH AMERICAN FLORA [VoLuME 34 
17. Porophyllum Pittieri Rydberg, sp. nov. 
A slender glabrous shrub; branches slender, purple, striate; leaves opposite; petioles 
2-5 mm. long; blades thick, elliptic, rounded at each end, less than 1 cm. long, usually with a 
single gland on each margin and one at the apex; heads in small cymes or solitary; peduncles 
1-2 em. long; involucre cylindro-campanulate, 1 cm. high, purplish or pink; bracts 5, linear, 
acuminate, with 2 rows of linear glands; flowers 15-20; corollas purplish, 8 mm. long; tube 
puberulent, several times as long as the funnelform throat; lobes narrowly lanceolate; achenes 
7 mm. long, hispidulous, decidedly tapering above; pappus ochroleucous, slightly tinged with 
purple at the tips, 7 mm. long; bristles hispidulous. 
Type collected at Cuesta de Quililha, near Purulha, Baya Verapaz, Guatemala, 1905, Pittier 
146 (U.S. Nat. Herb.). 
18. Porophyllum brachypodum B. L. Robinson, Proc. Am. Acad. 
35: 341. 1900. 
A shrub, with strict shining stems, branched above; leaves alternate, short-petioled; blades 
thick, entire, lanceolate to linear, tapering at both ends, but blunt at the apex, 3-4 cm. long, 
4-8 mm. wide; glands marginal; heads in dense corymbs; peduncles only 5-8 mm. long, 
slightly clavate, spreading; involucre campanulate, 8-9 mm. high; bracts oblong, obtuse, 
pale-green, with membranous margins, round-keeled on the back, with 2 rows of glands; 
flowers about 15; corollas 7 mm. long, whitish, pale with darker lines; tube puberulent, longer 
than the elongate-funnelform throat; achenes black, hispidulous, 7-8 mm. long; pappus 
6-7 mm. long, straw-colored; bristles scabrous. 
Type LocaLity: Guaymas, Sonora. 
DISTRIBUTION: Known only from the type locality. 
19. Porophyllum pausodynum Rob. & Greenm. Proc. Am. Acad. 
aVoe ey, UsWeXey. 
Boronia Seemanni S. Wats. Proc. Am. Acad. 24: 57. 1889. Not P. Seemannii Schultz-Bip. 
A shrub, with erect, at first green, later reddish branches, angled, sulcate and somewhat 
glaucous; leaves alternate, subsessile; blades narrowly linear-oblanceolate or linear, narrowed at 
both ends, but often blunt at the apex, slightly succulent, 4-6 cm. long, 2-5 mm. wide, entire, 
with 2 or 3 ellipsoid marginal glands on each side and one at the apex; heads in dense cymes; 
peduncles 0.5-2 em. long; involucre campanulate, about 1 cm. high, pale-green; bracts 5, 
oblong, obtuse, with 2 rows of linear glands; flowers 25-30; corollas white, 7-8 mm. long; 
tube puberulent, much longer than the narrowly funnelform throat; lobes narrowly lanceolate; 
achenes light-colored, or at last dark, 7 mm. long, hispidulous; pappus straw-colored, 6-7 mm. 
long; bristles hispidulous. 
TYPE LOCALITY: Guaymas, Sonora. 
DISTRIBUTION: Sonora. 
20. Porophyllum confertum Greene, Leaflets 2: 155. 1911. 
A suffrutescent perennial; stems 5 dm. high or more, green, terete, glabrous, striate, with 
ascending branches; leaves mostly alternate, subsessile; blades linear, narrow, 4-6 cm. long, 
less than 2 mm. wide; heads short-peduncled, in dense corymbs; peduncles usually less than 
1 cm. long; involucre narrowly campanulate, about 1 cm. high, 3 mm. broad; bracts 5, linear, 
obtuse, green, glabrous, with 2 rows of oblong glands; flowers 5—7; corollas ochroleucous, 7 mm. 
‘long; tube slender, about twice as long as the funnelform throat; lobes lanceolate; achenes 
7 mm. long, minutely puberulent, tapering at the apex; pappus 5 mm. long, straw-colored, 
sometimes tinged with purplish; bristles hispidulous. 
Type Locatity: Ceralvo Island, Gulf of California. 
DISTRIBUTION: Known only from the type locality. 
