Rhododendron alabamense |
Rhododendron cumberlandense |
|
---|---|---|
Alabama azalea |
Cumberland rhododendron, diploid flame or Cumberland azalea |
|
Habit | Shrubs, to 3(–5) m, usually not rhizomatous. | Shrubs, to 2 m, usually rhizomatous. |
Stems | bark smooth to vertically furrowed, shredding; twigs scattered, multicellular eglandular-hairy (hairs unbranched), otherwise glabrous or moderately unicellular-hairy. |
bark smooth to vertically furrowed, shredding; twigs very sparsely to conspicuously multicellular eglandular-hairy (hairs unbranched), otherwise glabrous or densely unicellular-hairy. |
Leaves | deciduous; petiole unicellular- and stipitate-glandular-hairy; blade ovate to obovate, 4–7.7(–9.4) × 1.2–2.5(–3.3) cm, thin, membranous, margins entire, plane, ciliate, eglandular-hairy, apex acute to obtuse, often mucronate, abaxial surface glabrous or unicellular-hairy, adaxial surface usually scattered eglandular-hairy, usually also unicellular-hairy. |
deciduous; petiole usually multicellular eglandular-hairy and usually unicellular-hairy; blade ovate to obovate, 3.1–8.1 × 1.3–3.5 cm, thin, membranous to chartaceous, margins entire, plane, unicellular-ciliate, apex acute to obtuse, often mucronate, abaxial surface glabrous or very sparsely eglandular-hairy, (usually glaucous), adaxial surface glabrous or sparsely scattered eglandular-hairy. |
Inflorescences | 6–7-flowered; bracts similar to bud scales. |
3–7-flowered; bracts similar to bud scales. |
Pedicels | 4–12 mm, eglandular- and/or stipitate-glandular-hairy, otherwise glabrous or moderately unicellular-hairy. |
4–9 mm, eglandular-hairy, rarely stipitate-glandular-hairy (then sepals eglandular), otherwise sparsely to densely unicellular-hairy. |
Flowers | opening before or with leaves, erect to horizontal, very fragrant; calyx lobes 0.1–3 mm, scattered eglandular-hairy and/or stipitate-glandular-hairy, otherwise sparsely to moderately unicellular-hairy, margins eglandular-hairy; corolla white, sometimes pink-tinged, with contrasting yellow blotch on upper lobe, funnelform, 25–42 mm, scattered stipitate-glandular-hairy (hairs often continuing in lines up lobes), otherwise sparsely to moderately unicellular-hairy on outer surface, petals connate, lobes 9–21 mm, tube usually ± gradually expanded into lobes, 15–31 mm (longer than lobes); stamens 5, much exserted, ± unequal, 37–69 mm. |
opening after leaves have expanded, erect to horizontal, acrid-scented; calyx lobes 1–3 mm, scattered, long-stipitate, usually eglandular-hairy, and unicellular-hairy, margins extremely long stipitate-eglandular-hairy (rarely long stipitate-glandular-hairy, then pedicels eglandular); corolla red, with indistinct blotch or darker-colored region on upper lobe, funnelform, 27–45 mm, scattered stipitate-glandular-hairy, otherwise ± densely unicellular-hairy on outer surface, petals connate, lobes 14–30 mm, tube abruptly expanding into lobes, 14–24 mm (equaling or much longer than lobes); stamens 5, much exserted, ± unequal, 42–62 mm. |
Capsules | borne on erect pedicels, 14–22 × 3–4 mm, sparsely to moderately multicellular eglandular-hairy, otherwise moderately to densely unicellular-hairy. |
borne on erect pedicels, 12–28 × 5–8 mm, sparsely to densely long stipitate-eglandular-hairy and sparsely to moderately unicellular-hairy. |
Seeds | without distinct tails; testa expanded, dorsiventrally flattened, ± loose. |
without distinct tails, flattened portion of testa may be well developed at each end; testa expanded, dorsiventrally flattened, ± loose. |
Floral | bud scales glabrous or glabrate abaxially, margins unicellular-ciliate. |
bud scales glabrous abaxially, margins usually ciliate distally, glandular proximally. |
2n | = 26. |
= 26. |
Rhododendron alabamense |
Rhododendron cumberlandense |
|
Phenology | Flowering spring. | Flowering summer. |
Habitat | Open, dry woodlands, rocky slopes | Ridge tops, mixed deciduous forests |
Elevation | 0-500 m (0-1600 ft) | 300-1800 m (1000-5900 ft) |
Distribution |
AL; FL; GA; MS; TN
|
AL; GA; KY; NC; SC; TN; VA |
Discussion | Rhododendron alabamense may be most closely related to a clade containing orange-red-flowered species (K. A. Kron 1993). This species has sometimes been confused with R. eastmanii; R. alabamense flowers before or as the leaves expand whereas R. eastmanii flowers after the leaves have expanded. Hybrids with R. canescens are known. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Rhododendron cumberlandense has a geographic distribution that is concentrated in the Cumberland Plateau and Mountains region with some populations in the southern Blue Ridge. It is most closely related to R. calendulaceum and can be distinguished from the latter by its flowering well after the leaves have expanded, eglandular pedicel and sepal margins, and usually abaxially conspicuously glaucous leaves. Hybrids are known with R. arborescens and R. viscosum. Rhododendron bakeri (Lemmon) Skinner very likely represents a hybrid between R. flammeum and R. canescens, although it has often been synonymized with R. cumberlandense (see K. A. Kron 1993). (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Source | FNA vol. 8, p. 467. | FNA vol. 8, p. 471. |
Parent taxa | ||
Sibling taxa | ||
Synonyms | Azalea alabamensis | Azalea cumberlandensis |
Name authority | Rehder: in E. H. Wilson and A. J. Rehder, Monogr. Azaleas, 141. 1921 , | E. L. Braun: Rhodora 43: 33. 1941 , |
Web links |