599 BLAKE. 
utrimque acuminata longe petiolata subintegra caulina 3-4 (infra 
mediam partem caulis). Capitula majuscula longe pedunculata, 
pedunculis basi unibracteatis. Flores radii ca. 10 flavi, disci numerosi 
flavi.— Species unica Helianthella madrensis Wats. 
PionocarPus madrensis (Wats.) Blake, n. comb.— Helianthella 
madrensis Wats.! Proc. Am. Acad. xxiii. 278 (1888).— Carmuanua: 
pine plains, base of the Sierra Madre, 19 Sept. 1887, Pringle 1302 
(TYPE COLL.: Kew). 
The genus Pionocarpus (riyv, fat, and xap7és, fruit) is distinguished 
from Helianthella chiefly by characters of the achene and style. The 
achenes of Pionocarpus are strongly thickened, unmargined, and 
broadly truncate at apex, and the style-branches bear a long hirtellous 
appendage. In Helianthella, on the contrary, the achenes are very 
flatly compressed, as in Encelia, are more or less distinctly white- 
margined, and at the true apex are much narrower than the body, 
the more or less united squamellae being borne in a notch at the sum- 
mit of the achene between the two awns. From Phoebanthus, to 
which its relationship is rather closer, Pionocarpus is separated by its 
habit and by the much more conspicuous squamellae. 
PreryMENtvM blepharolepis Blake, n. sp. Frutexramosus. Cau- 
lis densissime strigillosus cortice cano-brunneo tectus aetate glabratus; 
rami tenues subquadrangulares strigillosi fusco-brunnei. Folia oppo- 
sita ovata subacuminata basi cuneata vel cuneato-rotundata trinervia 
appresse serrata (dentibus 7-8-jugis) supra viridia strigillosa pilis 
basi tuberculatis subtus pallidiora non canescentia strigosa et strigil- 
losa plus minusve glanduloso-adspersa 2.5-3.8 cm. longa 10-17.5 mm. 
lata. Petioli tuberculato-strigosi 2 mm. longi. Capitula 1.5-2 cm. 
lata in apicibus ramorum 5-7 sublaxe cymoso-paniculata in pedun- 
culis axillaribus et terminalibus strigillosis 1.2-4.5 cm. longis. Discus 
7-9.5 mm. altus 6-8 mm. crassus. Involucri 3-sub-4-seriati gra- 
dati 7 mm. alti squamae exteriores ovatae interiores ovato-lanceo- 
latae plus minusve strigillosae et ciliatae infra subinduratae pallidae 
ca. 5-nerviae apice laxo angustato subacuto herbaceo. Radii 8 fer- 
tiles aurei oblongo-ovales bidenticulati in venis dorso plus minusve 
puberuli 7-5 mm. longi 3 mm. lati. Corollae disci aureae in dentibus 
hirtellae 4.8—5 mm. longae (tubo 1.4-1.5 mm.). Paleae obtusae su- 
pra strigillosae in margine et carina spinuloso-ciliolatae 5.8-7 mm. 
longae. Achaenia juventate plus minusve piloso-hispida maturita- 
tem vergentia sparse hispidula. Pappi aristae ca. 12 caducae ad 
1.3 mm. longae subaequales (2 longioribus 3 mm. longis exceptis).— 
Pursia: Coxcatlan, alt, 2135-2440 m., Sept. 1909, Purpus 4143 
