Old man of the Andes cactus is just one of several hairy species

The cactus family is chock-full of old men and old ladies. Enough so that they deserve their own membership wing in the AARP. Ha, we kid, but the “old …” cacti all share an eye-catching attribute: a coat of protective white hairs. That hairiness, while not of identical density, can make it tough for nonexperts to distinguish individual species from one another. Today, though, we’re singling out one senior cactus in particular: Oreocereus celsianus, aka old man of the Andes. The prefix, Oreo, means “mountain,” from the Greek word oros.