BLAKE—-NEW GENUS HEMIBACCHARIS, 551 
A variable species, usually readily distinguished by the short harsh pubes- 
cence of the stems and upper leaf surfaces. The pistillate heads contain 
about 37 to 48 pistillate flowers, with the filiform corolla tube terminated by 
a minute erect ligule about 0.5 mm. long, much shorter than the style, and 
3 or 4 hermaphrodite flowers; the staminate heads are about 28-flowered. 
The name mucronata is here taken in its traditional sense, although the 
description is not particularly applicable. 
10a. Hemibaccharis mucronata paniculata (Donn. Smith) Blake. 
Diplostephium paniculatum Donn. Smith, Bot, Gaz, 23: 8. 1897. 
Type LocALITy: Between San Martin and Todos Santos, Huehuetenango, 
Guatemala. 
SPECIMENS EXAMINED: 
Veracruz: Orizaba, Botteri 496/821 (N). 
Srare oF Mexico: Salto de Agua, 1905, Purpus 1502 in part (N). Ameca- 
meeca, 1899, Deam (G). 
Oaxaca: Sierra de Clavellinas, altitude 2,745 meters, 1894, C. L. Smith 
260 (N). 
CHIAPAS (7): Mountains around San Cristébal Las Gasas, Ghiesbreght 
524 (G). 
GUATEMALA: Between San Martin and Todos Santos, Huehuetenango, 
altitude 2,135 to 2,590 meters, December 25, 1895, Nelson 3629 (type; 
N). Casillas, 1892, Heyde € Lue 4251 (G). San Rafael, 1915, Hol- 
away 21 (G). 
Although typical specimens of this more southern form, with their densely 
cinereous- or canescent-tomentose stems and under leaf surface, are very 
distinct in appearance from typical plants of the species, they show no 
technical distinctions, and seem to represent a subspecies only. Several of the 
collections cited above under H. mucronata approach this form more or less 
closely, particularly Bourgeau 969, Purpus 1579, Nelson 2262, Pringle 11482, and 
several of Arséne’s specimens. 
11. Hemibaccharis irazuensis Bluke, sp. nov. 
Herbaceous above, the base not seen; stem purplish, sparsely branched above, 
densely and sordidly short-pilose with several-celled matted hairs, glabrescent 
below ; internodes 2 to 4 cm. long; petioles sordid-pilose, about 5 mm. long; leaf 
blades lance-ovate or lance-elliptic, 4 to 8 cm. long, 1.3 to 2.5 em. wide, acumi- 
nate, cuneate at base, subremotely mucronate-denticulate, papery, above densely 
pilosulous with somewhat deciduous subtuberculate-based hairs, roughish at 
maturity, beneath brownish green, densely sordid-pilosulous along the veins 
and veinlets and sparsely so between them, feather-veined ; panicles many- 
headed, rounded, 3.5 to 6 cm. wide, terminating the stem and the subterminal 
branches, the pedicels 2 to 6 mm. long, densely sordid-pilosulous; pistillate 
heads 4.5 to 5 mm. high, the pistillate flowers about 36, the hermaphrodite 4 
or 5; staminate heads 5 mm. high, about 32-flowered ; involucres about 5-seriate, 
graduate, 4.5 mm. high, the linear-lanceolate phyllaries acute to acuminate, 
green-centered, scarious-margined, ciliolate, the outer somewhat puberulous 
dorsally ; teeth of the staminate corollas longer than throat, the style branches 
linear, acute, hispidulous; achenes compressed, hispidulous, 1.2 mm. long, the 
brown-tinged pappus 3.5 mm. long; pappus of hermaphrodite flowers scarcely 
dilated toward apex. 
Type (pistillate plant) in the U. S. National Herbarium, no. 577970, col- 
lected at Laguna del Reventado, Volefn de IrazG, Costa Rica, altitude 2,306 
meters, January 1, 1901, by H. Pittier (no. 14079). Duplicate (staminate 
plant) collected at the same time and place (no. 14078). 
