2. Phoradendron californicum Nuttall, J. Acad. Nat. Sci. Philadelphia, n. s. 1: 185. 1848.
Mesquite mistletoe Mesquite mistletoe
Phoradendron californicum var. distans Trelease; P. californicum var. leucocarpum (Trelease ex Munz & I. M. Johnston) Jepson
Subshrubs, pendent, 1–5(–20) dm, dioecious. Stems grayish green to reddish green (in full sun), densely hairy, hairs silvery white, closely appressed, becoming glabrate; internodes terete, 10–20(–30) × 1–1.7(–2.5) mm. Leaves grayish green, scalelike; blade triangular, 1.5–3 mm, apex acute; basal phyllotaxy transverse or median. Staminate inflorescence 5–25 mm, peduncle with 1(–2) internodes, each 0.5–3 mm; fertile internodes (1–)2–3(–5), each 6–14-flowered, biseriate, flowers 1–3 per column. Pistillate inflorescences 5–10 mm, elongating in fruit; peduncle with 1(–2) internodes, each 0.5–3 mm; fertile internodes (1–)2–4(–6), each 2-flowered, flowers 1 per bract. Flowers: petals 3(–4), 1–2 mm. Berries white, translucent yellowish, pinkish, orange-red, or maroon, globose, 3–6 × 3–6 mm, glabrous. 2n = 28.
Flowering late fall–winter. Desert scrub or washes with mesquite or acacia; 0–1800 m; Ariz., Calif., Nev., Utah; Mexico (Baja California, Baja California Sur, Sinaloa, Sonora).
Phoradendron californicum, like P. juniperinum, bears only scalelike leaves, but this character has evolved independently in the two species (V. E. T. M. Ashworth 2000). Phoradendron californicum differs by its different hosts (legumes versus conifers) and inflorescences with more than one fertile internode. Molecular data indicate that P. californicum is not part of the acataphyllous Boreales group in the sense of W. Trelease (1916) but allied with cataphyllous tropical species (Ashworth). Varieties and host races have been proposed but these are not recognized in the most recent monograph of the genus (J. Kuijt 2003). In addition to its primary hosts, Prosopis, Senegalia, and Vachellia, Phoradendron californicum has also been recorded from a number of other hosts including Condalia, Dalea, Ebenopsis, Havardia, Larrea, Olneya, Parkinsonia, and sometimes is hyperparasitic on Psittacanthus.