Bradleya 31/2013 pages 31 – 43 A putative Oreocereus x Echinopsis hybrid from southern Bolivia Urs Eggli 1 & Mario Giorgetta 2 1 Sukkulenten-Sammlung Zürich, Mythenquai 88, CH-8002 Zürich, Switzerland.
[email protected] 2 Mario Giorgetta, Oberfeldstrasse 87, CH-8408 Winterthur, Switzerland.
[email protected] Photographs by Mario Giorgetta Abstract: Solitary plants of the putative inter- parents, and appear to be sterile. The importance generic cross Oreocereus celsianus × Echinopsis of intergeneric and interspecific crosses in the evo- tarijensis were found on two independent occa- lution of Cactaceae is briefly discussed, and the sions in the same general region of S Bolivia relative ease with which intergeneric hybrids can (Dept. Potosí). The plants are described and illus- be artificially obtained in cultivation is contrasted trated. They are intermediate in general appear- with the apparent rarity of naturally occurring in- ance and flower characters between the supposed tergeneric hybrids. Based on available evidence, parents, and appear to be sterile. The importance the impact of natural intergeneric hybridization of intergeneric and interspecific crosses in the evo- on cactus evolution appears to be limited. lution of Cactaceae is briefly discussed, and the relative ease with which intergeneric hybrids can be artificially obtained in cultivation is contrasted Introduction with the apparent rarity of naturally occurring in- Hybridization, both intergeneric (i.e. between tergeneric hybrids. Based on available evidence, species of different genera) and interspecific (i.e. the impact of natural intergeneric hybridization between species of the same genus), is a well on cactus evolution appears to be limited. known fact in Cactaceae (e.g.