ROBINSON. —- DIAGNOSES OF AMERICAN EUPATORIEAB. 271 
II. DIAGNOSES AND NOTES RELATING TO AMERICAN 
EUPATORIEAE. 
Bry B..L. Rosrason; 
Ophryosporus venosissimus, n. comb. Eupatorium venosissimum 
Rusby, Mem. Torr. Bot. Club, vi. 57 (1896). The anthers of this 
species, even when examined with a compound microscope, show no ves- 
tige of an apical appendage. In other respects, such as the few subequal 
scales of the involucre, the species is in agreement with Ophryosporus. 
In habit and foliage it somewhat resembles O. Cumingii, Benth. 
THE GENUS AGERATELLA seems never to have received a formal or 
detailed characterization. It was originally founded (without generic 
description) upon two plants which Dr. Gray regarded as varieties of a 
single species. Hoffmann, in Engl. & Prantl, Nat. Pflanzenf. iv. Abt. 5, 
p. 137 (1890), also regarded the genus as monotypic and gave only a 
comparative, 2-line description of it. With the more abundant material 
now at hand it is clear that there aré two distinct species. The generic 
characters and specific distinctions may be recorded as follows : — 
AGERATELLA, Gray. Capitula homogama, cylindrica vel anguste cam- 
panulata, ca. 15-flora. Involucri squamae valde inaequales, in seriebus 
5 verticalibus imbricatae, exterioribus brevibus ovatis, interioribus lon- 
gioribus lanceolato-oblongis, intimis linearibus angustissimis deciduis pa- 
leiformibus. Receptaculum hemisphaericum, nudum, parvum. Corollae 
anguste tubulosae sine ullis faucibus distinctis summa parte plus minusve 
contractae, externe sparse glandulosae, dentibus limbi 5 anguste oblongis 
brevissimis erectis. Autherae oblongae, basi obtusae, connectivo apice 
incrassato truncato vel in appendicem brevem obtusam p 
nia 5-gona, prismatica, deorsum leviter angustata, in costis sursum his- 
pidula. Pappi paleae ovatae vel lanceolatae, translucidae, erosae, costa 
unica hispidula in aristam longam purpurascentem producta. Styli rami 
elongati, leviter clavellati. — Gray ex Wats. Proc. Am. Acad. xxii. 419, 
420 (1887) ; Hoffm. in Engl. & Prantl, Nat. Pflanzenf. iv. Abt. 5, 
p- 137 (1890).— Frutices vel suffrutices graciles, humiles, ramosi. 
olia parva, opposita vel alterna, ovata vel oblonga vel linearia. Capit- 
ula numerosa, mediocra, racemosa vel paniculata. 
A. micropHytta, Gray, 1.¢. Fruticosa copiose paniculatim ramosa ; 
ramis gracillimis subteretibus decumbentibus puberulis apice nudiusculis 
