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.
Trichuris Trichuris, often referred to as whipworms (which typically refers to "T. trichiura" only in medicine, and to any other species in veterinary medicine), is a genus of parasite worms from the roundworm family Trichuridae, which is a type of helminth. The name whipworm refers to the shape of the worm; they look like whips with wider "handles" at the posterior end. The name "Trichocephalus" is sometimes used for this genus.