trigonous; the majority, however, are almost equally 
tetragonous. The plant from which the figure now given 
has been prepared is one that has been grown for many 
years in the Succulent House at Kew, where, planted in a 
shallow border, its stems attain a length of over 10 ft. 
These are woody at the base and armed with rather 
formidable spines. The flowers, which are produced freely 
in autumn and are very fragrant, are succeeded by red 
globose one-seeded berries. Like some allied species, 
A, tetragonus has a root system remarkable for the large, 
whitish, watery, ovate tubers which are formed along the 
principal roots, and are calculated to enable the plant to 
endure prolonged periods of drought. A. tetragonus is not 
difficult to grow, and is a useful plant for clothing pillars 
in a conservatory. 
Description. — Undershrub, climbing; roots bearing 
numerous translucent, elliptic tubers, 14 in, long, “4 1: 
thick, Stem cylindric, armed with stout decurved woody 
thorns, 6 lin. long ; twigs sharply triangular, straight, their 
angles scabrid. Cladodes usually in fascicles of 5, 3- or 
4-angled, linear, 7 lin, long, mucronate, their bases 
thickened. Racemes rather numerous, 24 in. long, spread- 
ing; bracts under 1 lin. long, membranous, brown; 
pedicels 1} lin. long, jointed below the middle. Perianth- 
segments obovate, 14 lin. long, white, obtuse, the outer 
distinctly erosely lobulate, the inner faintly toothed. 
Stamens rather shorter than the perianth ; anthers under 
3 lin. long, obtuse, faintly rose-coloured. 
globose; style short, thick, 3-lobed. 
broad, pink. 
Ovary sub- 
Berry globose, 3 lin. | 
Fig. 1, fascicle of 
cladodes ; %,a flower; 3 and 4, stamens; 5, pistil:—all 
enlarged, ee 
