odas] 
XV. On Two Genera of Plants from Chile. By Joux Mins, Esq., F.R.S, F.L.S. fc. 
Read November 18 and December 2, 1851. 
AMONG the few very interesting plants which I was enabled to collect during my rapid 
Journey over the Cordillera in 1825, were the two following, which being yet undescribed, 
may perhaps claim the attention of the Linnean Society. The first evidently belongs to 
the tribe of the Zriogoneæ, of which a monograph by Mr. Bentham was read before the 
Society in 1835, and subsequently published in the 17th volume of its Transactions. It 
differs from all others of the tribe in its habit, for its very slender ramifications are 
always dichotomously divided in every axil, and its solitary involucre, on a lengthened 
capillary pedicel, springs from the middle of each bifurcation; it is however easily distin- 
guishable from the rest by the proportion of its floral parts in a manner to be presently 
noticed. All the Hriogonee hitherto discovered in South America have been found on 
the western side of the Andes, and this is probably the first instance known of their 
occurrence on the eastern declivity. 
The learned author of the monograph above quoted, states that he does not agree with 
Dr. Meissner and M. DeCandolle, who infer the normal number of the stamens in the 
Polygonaceæ to be double that of the lobes of the perigonium, and that in all instances 
occurring with a less number of stamens, this diminution is alone attributable to the 
abortion of those parts. Mr. Bentham, on the contrary, shows that this relation is not 
at all manifest, and he endeavours to prove that the normal number of floral parts 
is always ternary, the six lobes of the perigonium being biserial, the nine stamens in 
three series, and the ovarium surmounted by three styles and three stigmata. This 
arrangement, however, is far from general, for the greater number of genera present only 
five divisions of the floral envelope, with six, eight or nine stamens. Atraphazxis, not- 
withstanding, offers a binary arrangement of its parts, viz. four lobes in the perianthium 
in two rows, six stamens with two styles, and two stigmata. 
The discrepances here alluded to may, however, be reconciled, if we pay attention to the 
following circumstances. There does not seem any apparent reason why botanists should 
have constantly regarded the floral envelopes in the Polygonaceæ as a perigonium or 
perianthium, words intended to express a confluence of calyx and corolla into one common 
floral covering; but here the parts constituting such envelope manifestly bear the usual 
characters of a distinct calyx and corolla, for the floral segments are divided to the base, 
and exhibit their origin externally upon an annular hypogynous ring, that serves to sup- 
port the stamens as well as the stipitate ovarium : they are always in two or more whorls, 
are deeply imbricated, the external series being of a somewhat denser texture, and although 
petaloid, these segments have every claim to be regarded as so many sepals, while the 
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