Rich as our gardens are in CacTEe®, and much as these are 
prized by cultivators on account of the singularity of the 
forms of some and the exquisite beauty of the blossoms in 
others, it is greatly to be lamented that the synonymy of 
those that are described is so faulty, and that so many are 
ill characterized ; every collection possessing many similar 
species under different names. With the opportunities we 
peculiarly enjoy, it may be expected that these difficulties 
in the way of a correct nomenclature will be obviated, 
although we almost despair of such an object being accom- 
plished but by the help of good figures, of which, thanks to 
our excellent assortment of species in the Royal Gardens of 
Kew and the kindness of our friends, we are already in pos- 
session of a considerable number. 
The present individual, especially, requires illustration. 
It is not uncommon in our stoves, and, at Kew, flowers rea- 
dily during the summer months; and with us, and probably 
at other places, it has borne the name of Opuntia Tuna; it 
being unquestionably the Cacrus Opuntia Tuna of Dr 
Canpotte (as regards his figure). This differs from the 
real Tuna of Dittenius, among other characters in its 
generally solitary spines. On this account it would appear 
that Wit.pEnow distinguished it by the name of mona- 
cantha, which Dre Canpotte himself, in his ‘‘ Prodromus,” 
has adopted ;—but he has referred, inadvertently, it would 
seem, to his “ Plantes Grasses,” n. 137 cum Tab. 2, which 
is his Cacrus coccinellifer (the Opuntia Tuna of Mutter and 
Preirrer). Premrer, on the other hand, quotes rightly 
the C. Opuntia Tuna of “ Plantes Grasses,” with its glau- 
cous articulations and nearly solitary spines; but he unfor- 
tunately adds the synonym of O. monacantha of Ker in 
Botanical Register, tab. 1726, which is a perfectly distinct 
plant from the original one of De Canpotte, having differ- 
ently-shaped articuli, of a bright, yet deep yellow-green 
hue, and strong, solitary spines, apparently quite destitute 
of the fascicles of sete at their base. 
It will be observed, that the spines of the present species, 
_ though usually solitary on the disk of the joints, are often 
geminate, or even fasciculate, at the margin. 
The colour of the flower of our plant is deeper than the 
figure of De Canpotze, but that appears to be the only 
difference between them. The species is supposed to be a 
native of Brazil. 
