About Pholisma arenarium Nutt.
Pholisma arenarium Nutt. is a species of flowering plant in the family Lennoaceae. It has several common names: desert Christmas tree, scaly-stemmed sand plant, and purple sand food. As one common name suggests, the loaf-shaped portion of its root is edible. This plant is native to northwestern Mexico, Arizona, and southern California, and grows in a range of habitat types including desert, chaparral, and sandy coastal dunes. It is a fleshy perennial herb that grows into a compact cylindrical or ovate form, reaching 20 to 30 centimeters in above-ground height, and often has part of its stem buried below the sandy surface. Pholisma arenarium is a parasitic plant that grows on the roots of various shrubs, including burrobush, Yerba Santa, California croton, rabbitbrush, and ragweeds. As a heterotroph that gets all its nutrients from other plants, it does not produce chlorophyll, and has a brownish-gray or whitish color. Hairy, glandular, pointed leaves grow along the surface of the plant. Flowers emerge between these leaves; each flower is roughly one centimeter wide, with a rounded corolla that ranges in color from lavender to deep or bright purple and has a white margin.
