Arceuthobium microcarpum

Plant: aerial parasitic shrub; 2-25 cm high, glabrous, dioecious; SHOOTS 4-6(-10) cm high, 1.5-2.5 mm wide at base, green to purple Leaves: reduced to minute scales INFLORESCENCE: axillary spikes Flowers: decussate (sometimes whorled), short pedicellate; STAMINATE FLOWERS 2.3 mm in diameter, the tepals 3(-4), with a central nectary, the perianth segments (2-)3-4(-5), each segment bearing a sessile, circular, uniloculate anther; PISTILLATE FLOWERS 1 mm in diameter, 1 mm long, with a single style and rounded stigma, the perianth segments 2, persistent Fruit: 3.5 mm long, 2 mm wide, bicolored, dehiscing explosively (to 15 m); pedicels curved at maturity; SEED without a thickened seed coat, eaten and distributed primarily by birds or dispersed explosively Misc: Mixed conifer forests; 2400-3150 m (7900-10400 ft); Aug-Sep Notes: HOSTS: Picea engelmannii and Picea pungens, also on Pinus aristata REFERENCES: Hawksworth, Frank G. 1994. Viscaceae. J. Ariz. - Nev. Acad. Sci. Volume 27(2), 241-245.

Duration: Perennial Nativity: Native Lifeform: Subshrub, Shrub General: Plants parasitic on Picea engelmannii, Picea pungens, and also Pinus aristata on the San Francisco Peaks; host forming small localized witches- brooms. Leaves: na Shoots: Green to purple, mostly 3-10 cm long, the base 1.5-3 mm wide; third internode mostly 5-7 times as long as wide. Flowers: Inflorescence of axillary paired-bracteate spikes; staminate flowers 2.5 mm in diameter, perianth lobes 3, usually deflexed at time of flowering; pistillate flowers with an inferior ovary, the perianth prolonged beyond the ovary into a short, conic cap, this cleft into 2 lobes at the apex; flowers August-September. Fruits: Berry, ellipsoid to ovoid, 3-4 mm long, 2 mm wide, blue- glaucous with a light brown apex. Ecology: Mixed conifer forests; 2400-3200 m (8000-10500 ft); Apache, Coconino, Graham, and Greenlee counties; southwestern U.S. Notes: Arceuthobium apachecum (Apache dwarf mistletoe) is parasitic on Pinus strobiformis; shoots are yellow-green, 3-7 cm long, the base 1-2 mm wide; in staminate flowers perianth lobes are 3-4. It occurs in mixed conifer forests of central and eastern Arizona at 2000-3100 m (6500-10000 ft). Arceuthobium abietinum (fir dwarf mistletoe) is parasitic on Abies concolor; shoots are yellowish, mostly 5-10 cm long; in staminate flowers perianth lobes are 3-4. In northern Arizona, it is only known to occur near the Grand Canyon, primarily along the North Rim, and with one population on the South Rim. Editor: Springer et al. 2008