400 CONTRIBUTIONS FROM THE NATIONAL HERBARIUM. 
The structures described as squamellae in this species are evidently strictly homol- 
ogous with the lateral lobes of the awns found in many other species, representing 
the latter in their extreme development. FF. collodes differs from the other Mexican 
species in its comparatively large, ovate, obscurely reticulate leaves and few large 
heads. . 
7. Flourensia pringlei (A. Gray) Blake, Proc. Amer. Acad. 49: 375. 1913. 
Helianthella pringlei A. Gray, Proc. Amer. Acad. 21: 389. 1886. 
Encelia oblonga Robins. & Fern. Proc. Amer. Acad. 30: 118. 1894. 
Stems numerous, suffrutescent, erect from a woody base, 30 to 40 cm. high, nearly 
simple or much branched, leafy, yellowish green becoming grayish, striate, glabrous; 
leaf blades 3.2 to 10 cm. long, 1.4 to 4.3 cm. wide, nearly uniform, elliptical-oblong 
to oblong-lanceolate, from round-tipped to acute, cuneate at base, with narrow crus- 
taceous tuberculate-hispidulous margin, somewhat resinous, often strigillose on margin, 
otherwise glabrous, venose, the lateral veins 7 to 11 pairs; petioles broad, flat, 1 to 2 
mm. long; heads solitary at tips of stems and branches, 2.5 to 4 cm. wide, on striate 
glabrous peduncles 6 to 13.5 cm. long; disk 1.3 to 1.5 cm. high, 1.5 to 2.5 cm. wide 
(in fruit 3 cm. wide); involucre 2-seriate, subequal or the outer phyllaries longer and 
overtopping the disk, often with some similar calyculate bracts at apex of peduncle, 
1.3 to 2.3 cm. high, the phyllaries linear-attenuate from a thickened, ovate or lanceo- 
late base, resinous and sparsely ciliolate; rays 14 to 20, golden-yellow, oval or oblong- 
oval, glabrous, 1 to 1.3 cm. long, 3.5 to 6 mm. wide; disk flowers glabrous, resinous, 
with short tube and long cylindric throat, 5.5 mm. long (tube 0.8 mm.); pales broad- 
ened upwardly, resinous toward the obtuse apex, 11 mm. long; achenes at maturity 
strongly thickened, densely villous, striate, 11 mm. long, 3.7 mm. wide; awns 2, 
ciliolate, firm, often somewhat recurved, 5 mm. long, often deciduous at maturity; 
squamellae none. 
Type LOcALITY: Rocky hills near Chihuahua City, Chihuahua, Mexico. 
SpecIMENS EXAMINED: 
Curmuanua: Rocky hills near Chihuahua City, September 7, 1885, Pringle 646 
(type collection of H. pringlei; B, G, K, N). Plains near Casas Grandes, 
October 10, 1891, Hartman 812 (type collection of FE. oblonga; G, K). 
DurANGO: Santiago Papasquiaro, altitude 2,045 meters, 192 kilometers west 
of north from Durango City, 1896, Palmer 425 (B, G, K). El Oro to Guanacevi, 
1898, Nelson 4730 (N). 
Flourensia pringlei, the least shrubby member of the genus, is unique in its numer- 
ous low stems, its oblong subsessile leaves, and particularly in its characteristic 
phyllaries. 
8. Flourensia resinosa (T.S. Brandeg.) Blake, Proc. Amer. Acad. 49: 375. 1913. 
Encelia resinosa T,. S. Brandeg. Zoe 5: 240. 1906. 
Branching shrub, vernicose-resinous, the branches striate, brown, simple or again 
branched; leaf blades 3.3 to 6.5 cm. long, 1 to 1.8 cm. wide, narrowly oblong-elliptic, 
lance-elliptic, or lanceolate, acute at each end, mucronate, entire, resinous-punctate, 
pale green with yellowish costa, densely prominulous-reticulate, with about 18 pairs 
of weak lateral veins; petioles flattened, 2 to 4 mm. long; heads 1 to 4, terminal and axil- 
lary, 3.5 to 5.3 cm. wide, on peduncles 6 to 7 cm. long; disk 1.1 to 1.4 cm. high, 1.3 to 1.7 
cm, thick; involucre 3-seriate, 7 to 9 mm. high, scarcely graduated, the phyllaries 
narrowly lanceolate, acuminate, herbaceous, infuscate below, very resinous, slightly 
ciliolate; rays 10, oblong, golden, 1.3 to 2.2 cm. long, 5.5 to9 mm, wide; disk corollas 
glabrous, 5.6 mm. long (tube 1 mm.); pales subacute, resinous at apex, 8.5 mm. long; 
immature achenes silky, 5 mm, long; awns 2, unequal, slender, at base strongly 
ampliate and more or less trifid, about 4.5 mm. long; squamellae none. 
Type Locauiry: Ixmiquilpan, Hidalgo, Mexico. 
