144 JOURNAL OF THE WASHINGTON ACADEMY OF SCIENCES VOL. 13, No. 8 
somewhat obcompressed-turbinate, 2.5 mm. long, 7-ribbed, whitish, densely 
ascending-pilose, bearing a short glabrous collar at apex; pappus 2-seriate, 
be copious, the outer aristae numerous, 0.8 mm. long, the inner 3.5 mm. 
ong. 
Type in the U. 8. National Herbarium, no. 1,135,594, collected on brushy 
hillside near Santa Ana, Department of Santa Ana, Salvador, altitude 655 
to 800 meters, January 8, 1922, by Paul C. Standley (no. 19703). 
ADDITIONAL SPECIMENS EXAMINED: Satvapor: Pine forest, vicinity of 
Santa Ana, altitude 655 to 900 meters, January 28 to 30, 1922, Standley 20413. 
A member of the section Hremosis, nearest Vernonia triflosculosa H.B.K. , 
but distinguished by its usually 5-flowered heads, its densely arachnoid- 
ciliate phyllaries (the outermost ovate, not suborbicular or suborbicular- 
ovate as in V. triflosculosa), and the much more conspicuous glabrous collar 
at apex of achene. The species is abundant on the slopes along the rail- 
road in the Department of Santa Ana, forming large masses, which are con- 
spicuous because of the white pappus of the closely crowded heads. 
Rensonia Blake, gen. nov. 
Shrub; leaves opposite, ovate, slender-petioled, large, serrate, scabrous; 
heads small, heterogamous, radiate, in terminal cymose panicles, the rays 
pistillate, fertile, the disk sterile; involucre turbinate-campanulate, 2-seriate, 
equal or subequal, the phyllaries 8 or 9, oblong-obovate, erect, indurate 
below, thick-herbaceous above; receptacle small, flat; outer pales flattish, 
the inner narrow, complicate; pistillate flowers about 8, about 1-seriate, 
their corollas ligulate, yellow, apparently small; disk flowers hermaphrodite, 
sterile, about 20, their corollas tubular, with slender tube, much longer 
eylindric-funnelform throat, and 5-toothed limb; anthers with minutely sagit- 
tate bases and ovate terminal appendages; style (hermaphrodite flowers) 
undivided, above thickened and hispidulous; ray achenes obovate, obcom- 
pressed, epappose, not at all coherent with the subtending phyllaries or the 
pales of the disk, 2-winged, the wings submembranous, narrow, nerved, en- 
tire or lacerate above, prolonged above the achene into two triangular lacerate 
teeth; disk achenes inane, elongate-clavate, trigonous, wingless, their pappus 
a short, thick, entire, hispidulous crown, with or without a single short, 
slender awn. 
This genus is named for Dr. Carlos Renson, who has been connected with 
the Salvador Department of Agriculture for more than thirty years, and 
whose botanical collections, a series of which is in the U. 8. National Her- 
barium, are the most extensive made in Salvador prior to Mr. Standley’s 
trip. It is a member of the Heliantheae-Melampodinae, to be inserted 
between Silphium L. and Schizoptera Turez. The former genus, no species 
of which is known south of the United States, consists of tall herbs with 
large, broadly campanulate or subglobose heads and 2 or 3-seriate rays. 
The monotypic genus Schizoptera Turez.,! known only from Ecuador, is an 
herb with a campanulate involucre of membranous-herbaceous outer and 
1See Blake, Hook. Icon. Pl. 31: pl. 3058. 1916, and Contr. Gray Herb. n. ser. 52: 
34. 1917. 
