Common plants include pinyon pine and juniper trees, sagebrush, tumbleweeds, and some short, sparse grasses. Suns was preferred over Scorpions, Rattlers, Thunderbirds, Wranglers, Mavericks, Tumbleweeds, Mustangs and Cougars. Invasive species include tumbleweeds, certain thistles, dandelions, and tamarisk. Many tumbleweeds are ruderal species, opportunistic agricultural weeds. "Tumbling Tumbleweeds" is a song composed by Bob Nolan. Examples include various tumbleweeds, "Bidens", ragweeds, thistles, and dandelion. It was featured in the 1935 Western films "Tumbling Tumbleweeds" and "The Phantom Empire". Evie Teal writes anonymous poems and ties them to tumbleweeds. Unusual mechanisms of wind dispersal include tumbleweeds. In the Asteraceae, the knapweed "Centaurea diffusa" forms tumbleweeds. The dried umbels detach from the plant, becoming tumbleweeds. Davis's other comics work includes "Tumbleweeds", "Gnorm Gnat" and "Mr. Potato Head". Both species are resurrection plants and form tumbleweeds. In the Plantaginaceae, "Plantago cretica" forms tumbleweeds. In the legume family (Fabaceae), "Baptisia tinctoria" and some species of "Psoralea" produce tumbleweeds.