468 Description of two new Species of Opuntia. 
with numerous scattered fasciculi of long elastic bristles strongly 
resembling hogs' bristles. 
Flowers solitary small, like those of 0. Hernandezii, a few toge- 
ther on the edges of the articulations, (Fig. b ) red, with the lanu- 
go in the areola on the ovarium dense, especially towards the upper 
parts, and with a dense tuft also surrounding its base. Outermost 
segmentsof the perianth somewhat scarious, cuneato-obcordate, with 
an apex, the innermost membranaceous petaloid obovate, emarginate, 
with a slight mticro. Stamens very numerous and crowded, covering 
the whole inner surface of the tube. Style cylindrical, stout, (flex- 
uous ?) with eight stigmata, which are thick, erect, and closely ap- 
pressed. 
This species grows in the lower regions of James's Island, one of 
the Galapagos, where the soil is extremely arid and rocky, and 
where it is the only plant of sufficient magnitude to afford any 
shade, the next in size forming nearly leafless bushes. The want 
of water is very great, and the succulent branches of these trees are 
eagerly devoured by the large tortoises from which the islands have 
received their name, by large lizards which also abound, and by va- 
rious other animals. Mr Darwin considers that they are occasionally 
furnished with a supply of this food from branches broken off by the 
wind. He found that lizards four feet in length were easily enticed, 
whenever he threw them a piece of a branch, and small birds would 
come within a few feet of him and peck at the one extremity, 
whilst the lizard was eating at the opposite end. 
Another Cactus was observed in these islands with the habit of 
Cereus peruvianus, but which does not attain to more than two or 
three feet in height. It is the first plant that takes possession of the 
newly formed beds of lava. Not finding it in flower, Mr Darwin 
did not preserve a specimen. 
Explanation of the Figures. 
Fig. I. ( a) an articulation with a flower ; (b) a petal ; ( c) a 
longitudinal section of the flower, shewing the position of the sta- 
mens, &c. All of the natural size. 
Fig. II. (a) part of a large articulation, with a young one at- 
tached to it ; ( b ) four flowers, one expanded, and three in bud, 
seated on the edge of an articulation ; (c) a longitudinal section of 
a flower bud enlarged ; (d) a sepal or outer segment of the pe- 
rianth ; (e) a petal or inner segment ; (f) a rough sketch of a 
tree. All, except c andyj of the natural size. 
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