19b. Ericaceae Jussieu subfam. Arbutoideae Niedenzu, Bot. Jahrb. Syst. 11: 135. 1889.
Gordon C. Tucker
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.
Genera 6, species 91 or 92 (6 genera, 70 species in the flora): North America, Mexico, Central America, Europe, n Africa, n Atlantic Islands (Canary Islands); most species endemic to western North America.
SELECTED REFERENCE 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.