TORCH THISTLES 237 
should not get saturated ; during winter, water should be almost entirely 
withheld. Give all possible exposure to bright sunshine, and the plants 
will do well. Some growers graft the more delicate species upon small 
rooted plants of Cereus. They are easily raised from seeds if these are 
sown on sandy soil, and placed in a sunny warm position, pricking off 
the seedlings as soon as they are large enough to handle. Most of the 
species develop offsets which may be removed and treated as cuttings. 
Description of Two species are figured—A, Mamillaria ‘pusilla, and 
Plate 116. B, M. rhodantha, both of the natural size. The separate | 
Figures 1 and 2 are an enlarged flower of M. rhodantha, and a section 
through the same. 
20URCe THISTLES 
Natural Order Cacrem. Genus Cereus 
Cereus (Latin, wax, or pliant; in allusion to the wax-like fleshiness 
of the young shoots, or to the pliant stems of some species). A large 
genus (two hundred species) of succulent stove or greenhouse perennials 
whose soft flesh contains a woody core. The stems are mostly long and 
angular, studded with rosettes of spines. The flowers are large and 
showy, tubular in form, composed of a large number of sepals and petals, 
most of which are brightly coloured. The stamens also are very numer- 
ous, united to the walls of the tube. The style is thread-like, divided at 
the summit. The species are distributed chiefly throughout Central and 
South America and the West Indian Islands. 
The genus Cereus has been represented in this country 
“exh for more than two hundred years, several species having 
been introduced in 1690: C. flagelliformis from Peru, C. hexagonus 
from Surinam, 0. lanuginosus and C. triangularis from the West Indies. 
Ten years later there came from Jamaica our first examples of C. 
grandiflorus. A few additional species turned up in the eighteenth 
century, beginning with C. tetragonus (1710) from South Armerica, and 
including C. heptagonus and C. repandus from the West Indies, C. 
peruvianus from Peru, and C. Royeni from South America—all in 1728. 
_ Several others were introduced towards the close of last century, but _ 
_ most of the species were unknown in our greenhouses until the present 
century, during which some of the finest have been introduced. Not 
many of these, however, may be easily obtained, and we content our- 
selves with describing a few species only. 
Il.—19 
