Rhododendron canescens |
Rhododendron canadense |
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mountain azalea, Piedmont or southern pinxterbloom azalea |
Canada rosebay, rhodora |
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Habit | Shrubs or trees, to 6 m, usually not rhizomatous. | Shrubs, to 1 m, rhizomatous. |
Stems | bark smooth to vertically furrowed, shredding; twigs scattered, multicellular eglandular- and/or stipitate-glandular-hairy (hairs unbranched), otherwise moderately to densely unicellular-hairy. |
bark ± smooth to slightly shredding; twigs sparsely multicellular eglandular- and shorter stipitate-glandular-hairy (hairs unbranched), also unicellular-hairy. |
Leaves | 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. |
deciduous; petiole multicellular eglandular- and stipitate-glandular-hairy and unicellular-hairy; blade elliptic to oblong or obovate, 1–8.3 × 0.4–3 cm, thin, membranous to chartaceous, margins entire, usually ± revolute, sometimes plane, eglandular- and unicellular-hairy, apex acute to rounded, abaxial surface eglandular- and stipitate-glandular-hairy, also unicellular-hairy, (± glaucous), adaxial surface scattered eglandular- and stipitate-glandular-hairy, also unicellular-hairy. |
Inflorescences | 6–19-flowered; bracts similar to bud scales. |
sometimes fasciculate, 3–9-flowered; bracts similar to bud scales. |
Pedicels | 4–17 mm, usually eglandular-hairy, rarely stipitate-glandular- and/or eglandular-hairy, otherwise sparsely to densely unicellular-hairy. |
3–10 mm, (usually glaucous), usually sparsely stipitate-glandular-hairy, and sometimes also densely unicellular-hairy. |
Flowers | 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. |
appearing before or, sometimes, with leaves, erect to horizontal, fragrant; calyx lobes 0.4–1.5 mm, often scattered stipitate-glandular-hairy, sometimes also unicellular-hairy, margins glandular- and/or eglandular-ciliate; corolla rose-purple to pink, rarely white, unspotted or red-spotted on upper 3 lobes, irregularly shaped, clearly 2-lipped due to very extensive connation of 3 upper lobes contrasting with 2 elongate, widely divergent lower lobes, 12–22 mm, glabrous or, sometimes, sparsely stipitate-glandular-hairy on outer surface, petals connate, upper lobe 3–8 mm, lateral lobes 12–22 mm (closely connate with upper lobe), lower lobes 12–22 mm, tube absent due to deep division between 2 lower lobes and between lateral and lower lobes; stamens 10, exserted, ± unequal, 9–20 mm. |
Capsules | borne on erect pedicels, 12–33 × 3–6.5 mm, usually sparsely to moderately eglandular-hairy, otherwise ± densely unicellular-hairy. |
borne on erect pedicels, 0.7–1.7 × 0.3–0.6 mm, multicellular stipitate-glandular- and eglandular-hairy and densely unicellular-hairy. |
Seeds | without distinct tails, flattened portion of testa well developed at each end; testa expanded, dorsiventrally flattened, ± loose. |
with flattened tails; testa tightly appressed. |
Floral | bud scales ± densely unicellular-hairy abaxially, margins usually unicellular-ciliate. |
bud scales unicellular-hairy abaxially, and often stipitate-glandular- and eglandular-hairy, margins unicellular-hairy. |
2n | = 26. |
= 52. |
Rhododendron canescens |
Rhododendron canadense |
|
Phenology | Flowering spring. | Flowering spring. |
Habitat | Moist to dry woods, pocosins, swamps and savannas, often along streams | Moist to dry, coniferous or mixed conifer-deciduous forests, thickets, open rocky areas, lake margins, bogs, swamps |
Elevation | 0-500 m (0-1600 ft) | 0-1900 m (0-6200 ft) |
Distribution |
AL; AR; FL; GA; IL; KY; LA; MS; NC; OK; SC; TN; TX
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CT; MA; ME; NH; NJ; NY; PA; RI; VT; NB; NF; NS; ON; PE; QC
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Discussion | 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.) |
Rhododendron canadense is distinctive and is most closely related to R. vaseyi; together they constitute sect. Rhodora (Linnaeus) G. Don (W. S. Judd and K. A. Kron 1995). Rhododendron canadense is sometimes cultivated for its showy flowers. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Source | FNA vol. 8, p. 469. | FNA vol. 8, p. 464. |
Parent taxa | Ericaceae > subfam. Ericoideae > Rhododendron | Ericaceae > subfam. Ericoideae > Rhododendron |
Sibling taxa | ||
Synonyms | Azalea canescens, Azalea candida | Rhodora canadensis |
Name authority | (Michaux) Sweet: Hort. Brit. ed. 2, 343. 1830 , | (Linnaeus) Torrey: in New York State, Rep. Geol. Surv., 151. 1841 , |
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