Mr. J. Miers on the genus Acnistus. dl 
which I possess specimens from Bonjean the original discoverer, 
differs by its rigid habit, with prominent hispid nerves to the 
leaves and calyces, by its erect anthers, and by the form and co- 
lour of its corolla, which in the present species scarcely differs 
from that of O. verna. As far as I can judge from dried speci- 
mens, the seeds of O. rotundata are considerably broader than 
those of O. verna: on the whole, the characters assigned appear 
to justify me in proposing this well-marked form as a new spe- 
cies, which like so many others must await the result of continued 
observation and experiment before it can be finally adopted by 
naturalists. 
V.— Contributions to the Botany of South America. 
By Joun Miers, Esq., F.R.S., F.L.S. 
[Continued from vol. iii. p. 451.] 
ACNISTUS. 
To this genus, as defined on a former occasion (Lond. Journ. 
Bot. iv. p. 835), I have to add another species. Subsequently 
(ibid. vu. p. 838) I alluded to the great proximity which this 
genus offers to Dunalia, and I may also add that it touches like- 
wise upon the section Chenesthes of Jochroma on the one hand, 
in a manner that renders it difficult to determine whether one 
species of Acnistus belongs to this or to the former genus ; on 
the other hand again it osculates closely upon Brachistus, so that 
B. oblongifolius from the length of its corolla (being twice that 
of its calyx) might almost be considered as an Acnistus : in this 
latter case however, as the plant has very dissimilar geminate 
leaves, a character peculiarly remarkable in most species of Bra- 
chistus, and as it presents only two, rarely more flowers in each 
axil, it cannot be considered as an Aenistus. 
14. Acnistus confertiflorus (n. sp.) ;—ramulis glabris, striatis ; 
foliis fasciculatis, oblongis, basi cuneatis, in petiolum longum 
gracilem attenuatis, apice obtusiusculis, supra pubescentibus, 
subtus fusco-tomentosis: floribus umbellato-fasciculatis, pe- 
dunculis apice incrassatis, calyeeque pilosiusculis, corolla lutea, 
glabra, lobis acutis, marginibus tomentosis, staminibus stylo- 
que subexsertis.— Peruvia, v. s. in herb. Lindley (Lobb. n. 328). 
In this species the leaves (including a petiole of 2 inch long) 
are 21 inches in length and 2 inch broad ; the peduncle is 9 or 
10 lines, the corolla 8 lines long: each axil usually presents four 
to five or six flowers, fasciculated with two to three or four young 
leaves, all growing out of the cicatrix of a fallen leaf of the pre- 
