Echinocereus dasyacanthus is a member of the cactus family, Cactaceae. It is one of about 2000 total species belonging to this family. The cactus is commonly known as Texas rainbow cactus because of the subtle rings or bands of contrasting colors along the stem of the plant. Not all Texas rainbow cacti have the "rainbow" coloration on their stems. Another common name is spiny hedgehog cactus. E. dasyacanthus can be identified as a tetraploid with predominantly yellow flowers. Experiments suggest this is due to the hybridization of E. dasyacanthus and E. coccineus. The E. dasyacanthus received its specific epithet from the two Greek words dasys and akantha, which mean "shaggy" and "thorns" respectively. Echinocereus dasyacanthus can be found on rocky slopes of arid mountains, desert floor, in desert grasslands and more mesic habitats. They are distributed throughout Arizona, New Mexico and Texas. It occurs in every county of Texas's Trans-Pecos region except for Val Verde. Texas rainbow cactus can also be spotted as far south as Sonora, Chihuahua, and Coahuila, Mexico. Echinocereus dasyacanthus plants are usually found with a single stem or 2-3 basal branches. Though it is not uncommon to find plants with 3-10 stems. The stems of Texas rainbow cactus are between 11–24 cm long and 5.5–7 cm wide and usually have 15-18 ribs. The spines usually overlap making the stem not visible. There is a great amount of variation in the spines characteristics. There are typically 4-12 central spines that are .5-1.2 cm long and 14-25 radial spines that are .7–2 cm long. The basic coloration of the spines are tan to yellow to pink. Some spines may be ashy-white to reddish brown, but that is less common. The flowering season for E. dasyacanthus is between the months of March and May. The large flower of the plant grow at the sides of the stem above the areoles close to the stem apex. The flowers are typically 8–12 cm long and 7–11 cm wide. The flowers smell sweet and are pollinated by bees. In the Trans-Pecos region of Texas the flowers are usually bright yellow with a green throat. Other color the flowers may be include dark to pale yellow, canary yellow, golden yellow or deep red to rose pink. Since this taxon of cacti are mostly yellow flowered, flowers that are beta cyanic and orange are less common. The tepals are relatively thick and durable compared to E. reichenbachii, but thin and soft compared to E. coccineus. The stamens of the flowers have filaments resulting in the floral throat being filled with a funnel of yellow anthers.
Opuntia macrorhiza is a common and widespread species of cactus with the common names plains prickly pear or twistspine pricklypear or Western pricklypear. It is found throughout the Great Plains of the United States, from Texas to Minnesota, as well as in the desert and Rocky Mountain states from Arizona to Idaho, with sporadic populations in the Mississippi and Ohio Valleys. It is also reported from northern Mexico, in the states of Chihuahua, Sonora, Coahuila, Nuevo León, Durango, Tamaulipas, and San Luís Potosí. The species is cultivated as an ornamental in other locations. The species prefers dry, sandy or gravelly soils. It is one of the shorter species of the genus, rarely over 30 cm (1 foot) tall, spreading horizontally and forming large clumps. Flowers are showy and bright yellow, sometimes with red markings near the base of the petals. Fruits are narrow, red, juicy and edible. Several varieties have proposed within the species. More study is needed to determine whether these should continue to be recognized as varieties, elevated to species status, or regarded as mere synonyms.