466 Description of two new species of Opuntia. 
X. Description of two new species of Opuntia ; with remarks on the 
Structure of the Fruit of Rhipsalis. By Rev. J. S. HENSLOW, 
M. A. Professor of Botany in the University of Cambridge. 
Sp. 1 . Opuntia Darwinii, prostrata, articulis globoso-ovatis, aculea- 
rum validioribus elongatis tricuspdiatis, floribus magnis solitariis. 
Plate XIV. Fig 1. 
THE terminal articulation (the only one seen) globoso-ovate, with 
distant areolae beset with short tomentum, and those towards the 
anterior extremity with four to six stiff spines of various lengths, 
of which the stoutest are one and a half inches long, evidently 
formed out of three combined, and whose points are free, so that the 
compound spine appears compressed and tricuspidate. They most- 
ly point forward, but some spread in all directions. Flowers soli- 
tary, larger than the articulations which they terminate, yellow. 
Perianth of six whorls, each of five parts, gradually passing from the 
form of small fleshy bracteal scales to membranous petaloid seg- 
ments j spirally arranged at somewhat more than the fifth of a cir- 
cle' asunder, so as to form five distinct secondary spirals, correspond- 
ing to'as many, formed by the areolae on the fleshy tube investing and 
surmounting the ovarium. These areolae are placed upon slight tuber- 
cular elevations, each bearing a small fleshy bracteal scale, in whose 
axil is a tuft of yellow tomentum, and those on the upper extremi- 
ty are also furnished with about half a dozen stiff acicular spines. 
The 'segments of the perianth pass gradually from the ovate-apicu- 
1 ate bracteal form of those in the outermost whorl to the cuneato- 
obcordate, and slightly mucronate petaloid form of those in the in- 
nermost, (Fig. b.) 
Stamens numerous, covering the inner paries of the fleshy tube, 
(Fig. c.) Style remarkably stout, cylindrical, with nine thick ra- 
diating stigmata, reaching above the fleshy tube, and a little beyond 
the uppermost stamens. Ovarium, a small cell, the width of the 
style, surrounded by the very thick fleshy walls of the lower part of 
tube or floral receptacle. The character of the herbage appears to 
agree with that of Cactus moniliformis, Lin., which De Candolle 
places in his division Opuntiaceae of the genus Cereus; and of which 
division he says, " An genus proprium inter Cereos et Opuntias 
medium ?" The flowers of our plant, however, are strictly those of 
an Opuntia. In assigning the character of " tubum supra ovarium 
nullum" to Opuntia, De Candolle must consider the whole of the 
fleshy tubular portion of the receptacle to which the stamens are at- 
