How are Obregonia and  Trichodiadema different from each other?
Obregonia Obregonia, the artichoke cactus, is a genus of cacti with a single species, Obregonia denegrii. The species is endemic to the state of Tamaulipas in Mexico.
Trichoadenoma A trichoadenoma (also known as a "trichoadenoma of Nikolowski") is a cutaneous condition characterized by a solitary, rapidly growing skin lesion ranging from 3 to 15mm in diameter.