Walter Röösli, *1948, optician and businessman in the eyewear industry. Between 1987 and 2009 he went on 22 trips to the drylands of Madagascar. These trips lasted between five and eleven weeks each. From 1987 to 1991, Bruno Rechberger was his travelling companion, and from 1992 to 2009, he travelled with Ralph Hoffmann. Together, they explored little known or unknown regions of Madagascar, discovering new succulent species, mainly from the genera Pachypodium, Uncarina, Aloe and Euphorbia and their respective companion plants.