Page:Memoir of a tour to northern Mexico.djvu/97

Rh Mexican plateau. This enormous cactus attained generally a height of 1 to 2 feet; specimens 3 feet high were rare, but one specimen was found which measured 4 feet in height, and near 7 feet in circumference; its top was covered with buds, flowers, and fruits, in all stages of development. In size it ranges next to Echinocactus ingens, Zucc, specimens of which 5 to 6 feet high were collected near Zimapan, in Mexico. Another Mexican cactus, E. platyceras, Lem., is said to grow 6, and even 10 feet high, and proportionately thick. E. Wislizeni is therefore the third in size in this genus.

From the same neighborhood a beautiful Mammillaria was sent in dried, as well as living specimens. It appears to be one of the few Mammillariae longimammae, though it differs in having purple, not yellow flowers, and stiffer spines. By the name I have given it. M. macromeris, I intended to indicate the unusually large size of different parts of the plant, the tubercles, the spines, and the flowers.

In the same region a strange plant was obtained for the first time, but then without flowers or fruit, and which, to the casual observer, appeared as curious as it is puzzling to the scientific botanist; single spiny sticks or stems having a soft and brittle wood, and a great deal of pith in the centre, one or more from the same root, but always without branches, 8 to 10 feet high, not more than half an inch thick, frequently overtopping the brush among which they were found, only towards the top with a few bunches of already yellow leaves. In the following spring the splendid crimson flowers of this plant were found by Dr. W. between Chihuahua and Parras, and to Dr. Gregg I am indebted for mature fruit, collected near Saltillo and Monterey. The plant proved to be a Fouquiera, two species of which had been found in Mexico by Humboldt; one of them, the F. formosa, a branching shrub, was only known in the flowering state; the other, F. spinosa, a spinous tree, only in fruit. The structure of the ovary of the first appeared to differ so much from that of the capsule of the second, that it was afterwards deemed necessary to distinguish both generically, and the second constituted then the genus Bronnia. Having both flowers and fruit of a third Fouquiera, I am enabled to solve the