Opuntia humifusa / Cactus Family April 29, 2006 I missed seeing the flowers of this cactus in bloom, we were a few weeks too early. It will have beautiful yellow flowers in May. These cacti are fairly common on the cedar glades. I've seen cacti in some places I never expected, the most surprising to me was near the beach in the U.S, Virgin Islands! Look at these interesting plants, but don't touch! The tiny thorns called "glochids" cause a lot of pain when they break off in your skin. Perennial