Rhododendron occidentale |
Rhododendron canescens |
|
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California azalea, western azalea |
mountain azalea, Piedmont or southern pinxterbloom azalea |
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Habit | Shrubs or trees, to 8(–10) m, usually not rhizomatous. | Shrubs or trees, to 6 m, usually not rhizomatous. |
Stems | bark smooth to vertically furrowed, shredding; twigs sparsely to densely multicellular stipitate-glandular-hairy or unicellular-hairy, or glabrous, sometimes only unicellular-hairy. |
bark smooth to vertically furrowed, shredding; twigs scattered, multicellular eglandular- and/or stipitate-glandular-hairy (hairs unbranched), otherwise moderately to densely unicellular-hairy. |
Leaves | deciduous; petiole multicellular eglandular- or stipitate-glandular-hairy and unicellular-hairy; blade ovate or obovate to elliptic, (2.5–)3.5–8.2(–10.8) × 1.2–2.9(–3.6) cm, thin, membranous, margins entire, plane, ciliate, eglandular-hairy, sometimes also stipitate-glandular-hairy, apex acute to obtuse, often mucronate, abaxial surface glabrous or sparsely unicellular-hairy, often also stipitate-glandular-hairy (or, rarely, stipitate-glandular- and eglandular-hairy), adaxial surface sparsely scattered, multicellular eglandular- and/or stipitate-glandular-hairy and unicellular-hairy, or glabrous. |
deciduous; petiole usually multicellular eglandular- or stipitate-glandular-hairy, also unicellular-hairy; blade ovate to obovate, 2.5–10(–13) × 1.2–3(–4) cm, thin, membranous to chartaceous, margins entire, rarely minutely serrulate, plane, inconspicuously ciliate, eglandular-hairy (hairs appressed to margins), apex acute to obtuse, often mucronate, abaxial surface densely to sparsely unicellular-hairy, sometimes glabrous or glabrate, often also scattered eglandular-hairy, adaxial surface usually scattered eglandular-hairy, otherwise sparsely unicellular-hairy, sometimes glabrous. |
Inflorescences | 3–15-flowered; bracts similar to bud scales. |
6–19-flowered; bracts similar to bud scales. |
Pedicels | 9–26 mm, stipitate-glandular- and, sometimes, also eglandular-hairy. |
4–17 mm, usually eglandular-hairy, rarely stipitate-glandular- and/or eglandular-hairy, otherwise sparsely to densely unicellular-hairy. |
Flowers | opening with leaves or after they have expanded, erect to horizontal, fragrant or mephitic-scented; calyx lobes 1–4(–9) mm, often stipitate-glandular- and/or eglandular-hairy, sometimes also unicellular-hairy, margins usually stipitate-glandular-hairy; corolla white with contrasting yellow blotch on upper lobe, white and pink or salmon, or pink with orange blotch on upper lobe, rarely white with yellow lines at throat, or with tube white to red, funnelform, 30–58 mm, stipitate-glandular-hairy and, rarely, also eglandular-hairy, otherwise sparsely to moderately unicellular-hairy or these hairs absent on outer surface, petals connate, lobes 13–29 mm, tube gradually expanding into lobes, 15–29 mm (equaling or longer than lobes); stamens 5, much exserted, ± unequal, 40–75 mm. |
opening before or with leaves, erect to horizontal, fragrant (usually musky-scented); calyx lobes 0.5–4 mm, surfaces and margins scattered stipitate-glandular- and/or eglandular-hairy, otherwise usually densely unicellular-hairy; corolla deep pink to white with pink tube, without blotch on upper lobe, funnelform, 23–46 mm, scattered, multicellular stipitate-glandular-hairy (hairs not forming distinct lines), otherwise sparsely to densely unicellular-hairy on outer surface, petals connate, lobes 7–20 mm, tube ± gradually expanded into lobes, 13–27 mm (equaling or longer than lobes); stamens 5, much exserted, ± unequal, 31–64 mm. |
Capsules | borne on erect pedicels, 12–22 × 4–14 mm, multicellular stipitate-glandular-hairy, sometimes also eglandular-hairy, otherwise sparsely unicellular-hairy (unicellular hairs rarely absent). |
borne on erect pedicels, 12–33 × 3–6.5 mm, usually sparsely to moderately eglandular-hairy, otherwise ± densely unicellular-hairy. |
Seeds | without distinct tails, flattened portion of testa well developed at each end; testa expanded, dorsiventrally flattened, ± loose. |
without distinct tails, flattened portion of testa well developed at each end; testa expanded, dorsiventrally flattened, ± loose. |
Floral | bud scales sparsely to densely unicellular-hairy abaxially, rarely also sparsely eglandular- or stipitate-glandular-hairy, margins unicellular-ciliate, or with glands and cilia mixed, or glandular. |
bud scales ± densely unicellular-hairy abaxially, margins usually unicellular-ciliate. |
2n | = 26. |
= 26. |
Rhododendron occidentale |
Rhododendron canescens |
|
Phenology | Flowering spring–summer. | Flowering spring. |
Habitat | Moist, wooded slopes and canyon bottoms, along streams, thickets, bogs, serpentine ridges, ocean bluffs | Moist to dry woods, pocosins, swamps and savannas, often along streams |
Elevation | 0-2700 m (0-8900 ft) | 0-500 m (0-1600 ft) |
Distribution |
CA; OR
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AL; AR; FL; GA; IL; KY; LA; MS; NC; OK; SC; TN; TX
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Discussion | The flowers of Rhododendron occidentale show an exceptional range of variation in color. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Rhododendron canescens is most similar to R. prinophyllum and R. periclymenoides, although these three species do not constitute a clade (K. A. Kron 1993); they occasionally hybridize where their habitats and ranges overlap. In addition, putative hybrids with R. alabamense, R. atlanticum, R. austrinum, R. flammeum, R. periclymenoides, and R. calendulaceum are known. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Source | FNA vol. 8, p. 467. | FNA vol. 8, p. 469. |
Parent taxa | Ericaceae > subfam. Ericoideae > Rhododendron | Ericaceae > subfam. Ericoideae > Rhododendron |
Sibling taxa | ||
Synonyms | Azalea occidentalis, Azalea californica, R. occidentale var. paludosum, R. sonomense | Azalea canescens, Azalea candida |
Name authority | (Torrey & A. Gray) A. Gray: in W. H. Brewer et al., Bot. California 1: 458. 1876 , | (Michaux) Sweet: Hort. Brit. ed. 2, 343. 1830 , |
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