ROBINSON.— ALOMIA, AGERATUM, AND OXYLOBUS. 483 
A. viscosum Ort. Dec. 36 (1797) = STEVIA SALICIFOLIA Cav. 
A. Wrightii Torr. & Gray ex Gray Proc. Am. Acad. i. 46 (1848) = 
TricHocoronts Wricutt (Torr. & Gray) Gray, Pl. Fendl. 65 (1849). 
3. REVISION OF THE GENUS OXYLOBUS. 
The claims of Oxylobus Moc. to generic rank rest quite as much 
upon habit and peculiar habitat as upon readily stated technical 
distinctions, yet they seem adequate. This small group of three well 
marked and obviously related species differ from all the Ageratums in 
being high alpine plants with thickish evergreen leaves. If a very 
doubtful report of one of them from Venezuela is excepted, they are 
confined to certain of the highest mountains of southern Mexico being 
found about at the timber line in borders of coniferous woods. The 
commonest of the three, O. arbutifolius, first described by Kunth as an 
Ageratum, was placed in Phania by DeCandolle, but is clearly distinct 
from that genus by the presence of a well developed apical appendage 
on the anthers. DeCandolle associated with it a second supposed 
species, his Phania trinervia, known to him only from one of Mocifio’s 
sketches. This second species has long remained vague, though 
Hemsley, Biol. Cent.-Am. Bot. ii. (1881), surmised its probable iden- 
tity with the earlier species of Kunth. To the writer it seems that this 
identity may now be stated with definiteness. The tracing of Mocifio’s 
sketch, reproduced in the Calques des Dessins, shows no difference 
which may not be readily explained by the crudeness of the draftsman- 
ship. The portion of Mexico in question has in recent years been dili- 
gently and effectively explored by several highly trained collectors 
Without the discovery of any second species of just this habit. Finally 
it may be remarked that the eldest DeCandolle appears to have known 
the Mexican flora chiefly from the collections of Mocifio & Sesse, 
Lagasca, Mendez, Née, and Haenke and on several occasions rede- 
Seribed unconsciously the species of Kunth, seeming never to have had 
adequate opportunities to examine the series of plants collected by 
Humboldt and Bonpland. 
The type of O. glanduliferus presents a curious confusion of more 
technical than practical importance. The species was first distin- 
guished and named, though not described, by Schultz-Bipontinus, who 
Pra herbarium sheets noted a typical bluish-flowered form and a white- 
agabes condition, which he labelled var. albiflorum Sch. Bip. It was 
. white-flowered variety which Hemsley later described as Ageratum 
#anduliferum Sch. Bip. and which accordingly becomes ipso facto the 
