CONTRIBUTIONS TO BOTANY. 
9 
opportunity of demonstrating the facts, and offering the reasons, 
upon which such an opinion is grounded, as I propose soon to 
publish the description of several curious genera belonging to 
the Olacaceee, Styraceee, &c. 
Cathedra. 
This is a veiy singular genus, which I proposed a few years 
ago, for an arborescent shrub that I found near llio de Janeiro^ 
having much the appearance of a Mijrsine, with which genus its 
flower agrees, in having a small cupshaped calyN, as many sta- 
mens as petals placed opposite to them, a short style and a cla- 
vate stigma, a depressed ovarium, which is unilocular, with seeds 
fixed to a central placenta. It differs however from that genus, 
in its almost entire calyx, in its petals and stamens being six in 
number, inserted upon the margin of a fleshy hemispherical or 
cupuliform disk, which is quite free both from the calyx and the 
ovarium, and in its remarkably thick fleshy petals with a tuft of 
long stiff hairs in the centre, and which are quite valvate in {estiva- 
tion, whereas in Myrsine they are thin in texture, and in aestivation 
are always more or less imbricated. M. A. DeCaudolle, in his 
‘Prodromus,' viii. p. 93, states, however, that they are valvate in 
M. variabilis and M. Paulensis, contrary to the usual structure of 
the genus ; but I find in the latter species, as also in M. Rapanea, 
and I believe in all the Brazilian genera, that the constantly thin 
margins of the petals always slightly overlap each other, espe- 
cially towards the apex : I was at one time, in like manner, mis- 
taken on this point, but on examining the buds with more atten- 
tion, I satisfied myself in regard to the fact in question. 
The somewhat bilobed tetragonous anthers in Cathedra consist 
of four cells quadi’ately placed around a centi-al connective, and 
formed of thick crystalline walls, composed of numerous long 
transverse cellules or hollow cylinders, closed at both ends, 
forming a honeycombed texture, and which are all arranged in 
a radiating series around each of the four pollen-cells, so that 
the external surface of the anther is thus reticulated or rather 
bullated with the small hexagonoid convexities of the ends of the 
cellules. Hence, at first sight, there does not appear any pro- 
vision for the escape of the pollen, but there may be perceived at 
length in the summit, four small circular depressions or spots, 
con-esponding with the apex of the pollen-cells, which are not open 
pores, but appear cancellated, as if the ends of the cellules, form- 
ing their covering, had there become dissolved, leaving a sieve- 
like screen over the cells, through the meshes of which, it may be 
inferred, that the fertilizing particles escape by a kind of endos- 
mose, and are conveyed by the villous tuft of long hairs belong- 
VOL. I. c 
