Ericaceae subfam. Arbutoideae

Shrubs or trees, multicellular hairs present or, sometimes, absent (Comarostaphylis); bark smooth, not furrowed, often flaky, sometimes shredding. Stems erect or prostrate. Leaves persistent (deciduous in Arctous), usually alternate, sometimes opposite or whorled (Ornithostaphylos), rarely opposite (Xylococcus); petiole usually present, sometimes absent (Arctostaphylos); blade plane, abaxial groove absent. Inflorescences terminal, panicles or racemes; perulae absent; bracts much shorter than sepals; bracteoles 2 or absent (Arctostaphylos, Arctous). Flowers pendulous; sepals (4-)5; petals (4-)5, connate, corolla deciduous, usually urceolate, sometimes cylindric, conic, or globose, lobes much shorter than tube; intrastaminal nectary disc present; stamens (8-)10; anthers dehiscent by slits or pores; ovary 2-10-locular; placentation axile; style straight. Fruits drupaceous (baccate in Arbutus), (pulp mealy or juicy), indehiscent; pyrenes 1-5, often connate into stonelike endocarp. Seeds 1-10, usually distinct, sometimes connate, globose (sometimes 3-sided), not winged.

Distribution

North America, Mexico, Central America, Europe, n Africa, n Atlantic Islands (Canary Islands), most species endemic to western North America.

Discussion

Genera 6, species 91 or 92 (6 genera, 70 species in the flora).

Selected References

Hileman, L. C., M. C. Vasey, and V. T. Parker. 2001. Phylogeny and biogeography of the Arbutoideae (Ericaceae): Implications for the Madrean-Tethyan hypothesis. Syst. Bot. 26: 131–143.

Lower Taxa

Arbutus, Arctostaphylos, Arctous, Comarostaphylis, Ornithostaphylos, Xylococcus