Arceuthobium campylopodum subsp. laricis

(M. E. Jones) Nickrent

Phytoneuron 2012-51: 9. 2012

Common names: Larch dwarf mistletoe
Endemic
Synonyms: A. laricis (M. E. Jones) H. St. John Razoumofskya laricis (M. E. Jones) Piper
Basionyms: Arceuthobium douglasii var. laricis M. E. Jones
Treatment appears in FNA Volume 12. Treatment on page 432. Mentioned on page 429.
Plants forming witches' brooms. Stems green, olive green, maroon, or purple, 4(–6) cm; third internode 5–8(–14) × 1–1.3(–2.5) mm, dominant shoot 1.5–3 mm diam. at base. Staminate flowers 2.7 mm diam.; petals 3(–4). Fruits 3.5 × 2.5 mm.

Phenology: Flowering Jul–Aug; fruiting (Aug–)Sep(–Oct).
Habitat: Coniferous forests, especially with western larch or mountain hemlock.
Elevation: 600–2300 m.

Distribution

V12 156-distribution-map.jpg

B.C., Idaho, Mont., Oreg., Wash.

Discussion

Meiosis occurs in June, with fruits maturing 13–14 months after pollination.

Larix occidentalis and Tsuga mertensiana are the principal hosts for subsp. laricis; secondary to rare hosts include Abies grandis, A. lasiocarpa, Picea engelmannii, Pinus albicaulis, P. contorta, P. monticola, and P. ponderosa. This dwarf mistletoe is a major pathogen on larch in Idaho and Montana.

References

None.

Lower Taxa

No lower taxa listed.