SUCCULENT PLANTS. 



477 



Boucerosia. — This genus and Caralluma are very nearly related, and 

 Mr. N. E. Brown, the great authority upon succulent Asclepiads, believes 

 that they should be united. They are Stapelia-like plants, but with 

 smaller flowers having a single corona, the Stapelia group, including 

 Duvalia and Huemia, having a double corona. B. Gussoniana ("Bot. 

 Mag.," t. 5087, as Apteranthes) has been well known as Stapelia 

 europaea. It is the most interesting member of the group, since it is 

 actually a native of Europe as well as of North Africa, being found in 

 Spain and on one of the Sicilian islands. It has small flowers, of 

 brown-purple colour much barred with yellow, in clusters of eight or ten, 

 at the tips of the branches. B. maroccana (" Bot. Mag.," t. 6137) is a 

 species which, though near the last, must be quite distinct. The flowers 



Fig. 87.— ' Mimicry.' Echidnopsis cereiformis and Euphorbia mamillaris 

 (on extreme right). 



are borne much below the tips of the branches, in clusters of four to five, 

 and though nearly of the same colour they are much less barred with 

 yellow. The flower-stalks are shorter. As the name indicates, it is 

 native of Morocco, and was introduced to Kew by Sir Joseph Hooker. 

 B. Munbyana, a native of Algeria, is also in cultivation. 



Aloe vera {A. vulgaris) is said to be native of the whole Mediterranean 

 region. 



Euphorbia. — The most important North African species is E. rcsinifera, 

 a native of Morocco. The stems are four-angled, and attain a height of 

 a yard and more. E. Beaumicreana is also a cactoid species from 

 Morocco, the stem nine- or ten-angled. Still another is E. Echinus, with 

 six-angled stems. The last is perhaps not in cultivation. 



