Arceuthobium campylopodum subsp. occidentale
Plants usually forming localized infections only. Stems yellow or orange, 8(–17) cm; third internode 7–12.7(–18) × 1.5–1.8(–3.5) mm, dominant shoot 1.5–5 mm diam. at base. Staminate flowers 3 mm diam.; petals 3–4. Fruits 4.5 × 3 mm.
Phenology: Flowering Sep–Nov(–Dec); fruiting (Sep–)Oct–Jan(–Feb).
Habitat: Coniferous and mixed forests, especially with digger pine.
Elevation: 30–1200 m.
Meiosis occurs in August, with fruits maturing 13 months after pollination.
Pinus sabiniana is the principal host of subsp. occidentale; secondary hosts include Pinus attenuata, P. coulteri, P. jeffreyi, and P. ponderosa, as well as some exotic species of pines. Subspecies occidentale occurs in the foothills surrounding the Central Valley and in the Coast Ranges.