Among the multitude of succulents cultivated in the Huntington’s Desert Garden are also a number of companion xerophytic trees and shrubs. Many of these function as nurse-plants much as they would in nature to protect other plants, including succulents, from scorching sun and extremes of temperature. Others are also grown for the intrinsic interest of the plants themselves. C. cacalaco fulfills both functions but stands out among other shrubs in the Desert Garden by virtue of its ornamental bark. Its branches are covered with corky tubercles that resemble those of the South African caudiciform Dioscorea elephantipes, though it is completely unrelated. Nevertheless, the tubercles of both are somewhat angular and on the sides of these miniature mountains of cork display growth-rings resembling geological strata. Those of the caesalpinia, however, are tipped by a claw-like prickle. HBG 97072, seedlings of HBG 26543, a plant from seed collected Feb 5, 1969, by J. Dodson (# 423) & Dudley Gold ca. 2 miles beyond Tlalizapan, in the state of Morelos, on the road that leads to Zacatepac and Tlalizapan from the toll road between Cuernavaca and Acapulco, Mexico. $8.
Published in the Cactus and Succulent Journal, Vol. 82 (2), March - April, 2010