Gymnocactus roseanus     (Böd.) Glass et Foster, comb. nov., Cact. Succ. Journ, 42: 234, 1970

Gymnocactus roseanus     Gymnocactus roseanus

Fig. 56 Gymnocactus roseanus comb. nov., a large, old cluster growing in the mountains north of Saltillo. The nature of this species has been misunderstood and it has been mistakenly placed in the Coryphanthanae. Fig. 57. Detail of the root and stem of G. roseanus, Gl. & F. 1696. The roots of this species seem to have a tendency to become tuberous, though it is difficult to detect where the roots stop and the stems begins, as the older portions of the stem often become covered by soil and assume the functions of roots. The young stem is pale green, the spines light yellow, and the flowers pinkish yellow.

The next morning we headed north on highway 57 to a spot a few miles out of the city where Horst Kuenzler of New Mexico Cactus Research had told us we could find "Thelocactus" roseanus. We checked out a likely mountain east of the road, and though in the literature they claim that this species is quite rare, we found considerable numbers of the plant growing up the steep hillside, usually in large, old clusters. It is surprising that Backeberg failed to recognize that this species belongs in his own genus, Gymnocactus. He mistakenly transferred Thelocactus roseanus to Escobaria, whereas the plant is clearly a member of the Echinocactanae and does not bear the grooved tubercles of Escobaria, nor does the flower arise from the axil, but near the spine bearing portion of the areole. In our opinion the genus Gymnocactus is a valid concept, comprising the small bodied, small flowered thelocacti with small naked fruit dehiscent along a longitudinal slit. This genus also has strong affinities to Turbinicarpus and the new genus Normanbokea. The yellow spined, caespitose T. roseanus is closely related to the new species we found north of El Pilar. Its relationships have heretofore been obscured and a source of confusion, and we would like at this time to propose the new combination:

Gymnocactus roseanus (Böd.) Glass et Foster comb. nov.

Echinocactus roseanus Böd. Zfs., 363. 1928. - Neolloydia roseana (Böd.) Knuth, Kaktus-ABC, 368. 1935. - Coryphantha roseana (Böd.) Moran, Gent. Herb., VIII:4, 318. 1953. - Thelocactus roseanus (Böd.) Marshall (1941).



© 2002-2007   Jan Mynar

Last modified January 25, 2007

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