Western white pine dwarf mistletoe Western white pine dwarf mistletoe

Arceuthobium monticola Hawksworth, Wiens & Nickrent, Novon 2: 205. 1992

Plants forming localized infections only. Stems olive green or brown, 5–7(–10) cm; third internode 8–12(–15) × 1.5–1.7(–2) mm, dominant shoot 2–4 mm diam. at base. Staminate flowers 3 mm diam.; petals 3. Fruits 4–4.5 × 2–2.5 mm.

Flowering Jul–Aug; fruiting Oct–Nov. Coniferous forests, especially with western white pine; 700–1900 m; Calif., Oreg.

Meiosis likely occurs in July, with fruits maturing 15 months after pollination.

The principal host of subsp. monticola is Pinus monticola; secondary to rare hosts include Picea breweriana, Pinus jeffreyi, and P. lambertiana. It is endemic to the Klamath and Siskiyou Mountains.