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Key to families | Table of families and genera

Specimen numbers are hyperlinked to records in the Consortium of California Herbaria data view where possible. Taxa are hyperlinked to entries in the Jepson Interchange via the "[Online Interchange]" link.


Perennial herb, shrub, glabrous. Stem: generally < 20 cm, ± angled at least when young, ± yellow, ± green, brown, purple; branches whorled or in 1 plane. Leaf: < 1 mm, scale-like. Inflorescence: generally spikes, peduncle short; flowers generally opposite, 4-ranked, less often whorled or 1, terminal. Staminate flower: perianth parts generally 3–4; anthers ± 1-chambered. Pistillate flower: perianth parts 2, persistent, minute. Fruit: generally 2–5 mm, broadly fusiform-spheric, 2-colored (1 color below, 1 above); pedicel short, recurved; seeds projected to 15 m by fruit explosion.
26 species: temperate, tropics northern hemisphere. (Greek: juniper, life) [Nickrent et al. 2004 Amer J Bot 91:125–138] Most important of timber pathogens; most species cause abnormal branching (witches' brooms) in hosts. Recent molecular studies support reunification of many western North American species under Arceuthobium campylopodum.

Key to Arceuthobium

1. Stem generally << 2 cm, 2° branches rare; on Pseudotsuga menziesii, rarely on associated Abies ..... A. douglasii

1' Stem > 2 cm, 2° branches many; on Abies, Pinus, Tsuga, rarely Picea breweriana

2. Larger branches whorled; on Pinus contorta subsp. murrayana, rarely on associated Pinus ..... A. americanum

2' Larger branches not whorled, in 1 plane; on Abies, Pinus (except Pinus contorta subsp. murrayana), Tsuga, rarely Picea ..... A. campylopodum


Citation for the whole project: Jepson Flora Project (eds.) [year] Jepson eFlora, [accessed on month, day, year]
Citation for an individual treatment: [Author of taxon treatment] [year]. [Taxon name] in Jepson Flora Project (eds.) Jepson eFlora, [URL for treatment]. Accessed on [month, day, year].
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