MISSOURI BOTANICAL GARDEN BULLETIN 77 
occasionally some of the columnar forms of Cereus are used 
in Mexico as hedge plants. A few forms of Cereus and a 
number of opuntias produce a very palatable fruit which 
is eaten raw or made into preserves. In emergencies the 
young growths of prickly pear have been used as food for 
stock. As regards the spineless forms, these have in all 
probability been unduly proclaimed as excellent stock food 
and as the solution of the problem of desert reclamation. A 
few members of the cactus family produce drugs which have 
a marked action on the nervous system, the “mescal button,” 
or “dumpling cactus,” yielding an alkaloid with a pro- 
nounced effect on the optic nerve. Many cacti are well worth 
cultivation as ornamental plants, some of them producing 
very attractive flowers. Among these may be mentioned the 
various forms of night and day-blooming cereus, “queen of 
the night,” and species of the genera Phyllocactus, Echinop- 
sis, and Epiphyllum. 
From what has been said it might appear that all cacti 
are succulent. There are, however, a few forms, like the 
pereskias of the subtropical regions of America with a 
moderate rainfall, which have relatively small stems and 
abundant thin-leaved foliage. Forms more or less inter- 
mediate between the leafy pereskias and the succulent, leaf- 
less, desert cacti, exist in the species of Pereskiopsis, growing 
in parts of Mexico having an annual rainfall which is inter- 
mediate between that of the desert and that of the regions 
to which the pereskias are indigenous. Representatives of 
both of these leafy genera are included in the Garden collec- 
tion and serve to emphasize the adjustment to extreme con- 
ditions which has taken place in the succulent desert-inhabit- 
ing species. Especial attention is called to the pereskias, 
several good specimens of which are at present in flower in 
one of the desert houses. 
The succulent euphorbias, of which the Garden has a 
large collection, almost parallel the cacti in fantastic forms 
of growth, and to an untrained eye the members of the two 
groups appear strikingly alike. The families, however, are 
widely separated. Euphorbias are to be found in the torrid 
and temperate regions of both hemispheres, the fleshy forms, 
however, being for the most part restricted to the arid regions 
of Africa, Arabia, and India, though a few small species 
occur in Texas and Mexico. The remarkable coincidence of 
form met with in the cacti and euphorbias may in part be 
due to the similar climatic and soil conditions to which they 
are exposed in their respective arid habitats. Like the cacti, 
the euphorbias have little economic value; a few are used 
