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Vascular Plants of California
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Arctostaphylos

MANZANITA

Higher Taxonomy
Family: EricaceaeView DescriptionDichotomous Key

Common Name: HEATH FAMILY
Habit: Perennial herb, shrub, tree. Stem: bark often peeling distinctively. Leaf: simple or 0, generally cauline, alternate, opposite (whorled), evergreen or deciduous, often leathery, petioled or not; stipules 0. Inflorescence: raceme, panicle, cyme, or flowers 1, terminal or axillary, generally bracted; pedicel often with 2 bractlets. Flower: generally bisexual, generally radial, bell-shaped, cylindric, or urn-shaped; sepals generally (0)4--5, generally free; petals generally (0)4--5, free or fused; stamens (2--5)8--10, free, filaments rarely appendaged, anthers dehiscing by pores or slits, awns 0 or 2(4), seemingly abaxial, reduced or elongate, generally curved; nectary generally present at ovary base, generally disk-like; ovary superior or inferior, chambers generally 1--5, placentas axile or parietal, ovules 1--many per chamber, style 1, stigma head- to funnel-like or lobed. Fruit: capsule, drupe, berry. Seed: generally many, winged or not.
Genera In Family: +- 100 genera, 3000 species: generally worldwide except deserts; some cultivated, especially Arbutus, Arctostaphylos, Rhododendron, Vaccinium. Note: Monophyletic only if Empetraceae included, as treated here. Ledum included in Rhododendron. Non-green plants obtain nutrition from green plants through fungal intermediates.
eFlora Treatment Author: Gary D. Wallace, except as noted
Scientific Editor: Gary D. Wallace, Thomas J. Rosatti, Bruce G. Baldwin.
Arctostaphylos
Habit: Shrub to small tree, prostrate to erect. Stem: old stems generally +- red, smooth, bark generally thin, peeling, or generally +- gray or red-gray, shredding and rough; burls at base, woody, sprouting after fire, or generally 0; twig hairs 0 or generally +- like those on inflorescence axes, bracts. Leaf: alternate, evergreen; blade flat to convex, base lobed to wedge-shaped, clasping stem or not, margins generally flat, surfaces with stomata generally both abaxially, adaxially, alike in color, hairiness, less often only or fewer abaxially, generally differing in color, hairiness. Inflorescence: +- raceme (generally 0--1-branched) or panicle (generally 2--10-branched), terminal, nascent inflorescence present following stem growth, generally late spring through winter, remaining dormant 4--6 months prior to flower (except in Arctostaphylos pringlei subsp. drupacea); branches 0 or raceme-like; flower bracts leaf-like, generally flat, or scale-like, often folded, keeled, tips rounded to acute to awl-shaped. Flower: radial; sepals 5(4), free, persistent; corolla conic to urn-shaped, lobes in number = sepals, short, rounded, curved back, white to pink; stamens 2 × number of sepals, included, filaments swollen, generally hairy at base, anthers dark red, awns elongate; ovary superior, on disk, 2--10-chambered, ovule 1 per chamber. Fruit: drupe, generally +- depressed-spheric to spheric; flesh generally thick, +- mealy, occasionally 0; stones 2--10, free, fused, or some fused.
Species In Genus: +- 62 species: North America (especially California) to Central America, Eurasia. Etymology: (Greek: bear berries) Note: Rosatti (1986 Syst Bot 12:61--77) showed that in Arctostaphylos uva-ursi little to none of the variation in hairs (including length, glandularity) is genetically based; Crowe & Parker (2023 Ecol Evol 13(3): e9801) detail variation in stone fusion.
Jepson eFlora Author: V. Thomas Parker, Michael C. Vasey & Jon E. Keeley
Reference: Keeley 1997 Madroño 44:109--111; Parker et al. 2007 Madroño 54:148--155
Index of California Plant Names (ICPN; linked via the Jepson Online Interchange)
Key to Arctostaphylos

Previous taxon: Arbutus menziesii
Next taxon: Arctostaphylos andersonii

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Citation for this treatment: V. Thomas Parker, Michael C. Vasey & Jon E. Keeley 2023, Arctostaphylos, in Jepson Flora Project (eds.) Jepson eFlora, Revision 12, https://ucjeps.berkeley.edu/eflora/eflora_display.php?tid=9173, accessed on January 26, 2025.

Citation for the whole project: Jepson Flora Project (eds.) 2025, Jepson eFlora, https://ucjeps.berkeley.edu/eflora/, accessed on January 26, 2025.