The green links below add additional plants to the comparison table. Blue links lead to other Web sites.
enable glossary links

clammy azalea, swamp azalea

Alabama azalea

Habit Shrubs or trees, to 7 m, rhizomatous or not. Shrubs, to 3(–5) m, usually not rhizomatous.
Stems

bark smooth to vertically furrowed, shredding;

twigs sparsely to conspicuously multicellular eglandular-hairy (hairs unbranched), otherwise glabrous or densely unicellular-hairy.

bark smooth to vertically furrowed, shredding;

twigs scattered, multicellular eglandular-hairy (hairs unbranched), otherwise glabrous or moderately unicellular-hairy.

Leaves

deciduous;

petiole usually multicellular eglandular-hairy and unicellular-hairy;

blade ovate to obovate, 2–7(–9) × 1–3(–3.8) cm, ± thin, membranous to chartaceous, margins entire or, sometimes, minutely serrulate, plane, ciliate, eglandular-hairy, apex acute to obtuse, often mucronate, abaxial surface glabrous or densely unicellular-hairy, adaxial surface (lustrous or dull), glabrous or sparsely scattered eglandular-hairy, sometimes also sparsely unicellular-hairy.

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.

Inflorescences

3–14-flowered;

bracts similar to bud scales.

6–7-flowered;

bracts similar to bud scales.

Pedicels

5–27 mm, stipitate-glandular- or, sometimes, eglandular-hairy, otherwise sparsely to densely unicellular-hairy.

4–12 mm, eglandular- and/or stipitate-glandular-hairy, otherwise glabrous or moderately unicellular-hairy.

Flowers

opening after leaves, erect to horizontal, slightly to strongly fragrant (most noticeable at night);

calyx lobes 0.5–5 mm, surfaces and margins scattered stipitate-glandular-hairy or, sometimes, eglandular-hairy, often also unicellular-hairy;

corolla white, sometimes pink-tinged or pink (not strongly contrasting with white or greenish to pinkish style or filaments), without blotch on upper lobe, funnelform, 20–58 mm, usually scattered, often conspicuously stipitate-glandular-hairy (hairs continuing in lines up lobes), otherwise sparsely to moderately unicellular-hairy on outer surface, petals connate, lobes 7–21 mm, tube usually ± gradually expanded into lobes, 13–37 mm (equaling or much longer than lobes);

stamens 5, much exserted, ± unequal, 21–65 mm.

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.

Capsules

borne on erect pedicels, 7–20 × 3–7 mm, usually densely stipitate-glandular- and/or eglandular-hairy, otherwise densely unicellular-hairy to ± glabrous.

borne on erect pedicels, 14–22 × 3–4 mm, sparsely to moderately multicellular eglandular-hairy, otherwise moderately to densely unicellular-hairy.

Seeds

without distinct tails, flattened portion of testa well developed at each end;

testa expanded, dorsiventrally flattened, ± loose.

without distinct tails;

testa expanded, dorsiventrally flattened, ± loose.

Floral

bud scales glabrous or densely unicellular-hairy abaxially (sometimes with sharply marked, dark brown band along distal margins), margins unicellular-ciliate or, sometimes, glandular-serrulate.

bud scales glabrous or glabrate abaxially, margins unicellular-ciliate.

2n

= 26.

= 26.

Rhododendron viscosum

Rhododendron alabamense

Phenology Flowering spring–summer. Flowering spring.
Habitat Acid swamps, bogs, seepage slopes, pocosins, streamheads and baygalls, wet pine flatwoods, moist pine or pine/oak forests, hummocks, shrub balds Open, dry woodlands, rocky slopes
Elevation 0-1500 m (0-4900 ft) 0-500 m (0-1600 ft)
Distribution
from FNA
AL; AR; CT; DE; FL; GA; LA; MA; MD; ME; MS; NC; NH; NJ; NY; OK; PA; RI; SC; TN; TX; VA; VT
[WildflowerSearch map]
[BONAP county map]
from FNA
AL; FL; GA; MS; TN
[WildflowerSearch map]
[BONAP county map]
Discussion

Rhododendron viscosum is the most widespread and variable species of sect. Pentanthera and has been divided into as many as four species: R. coryi, R. oblongifolium, R. serrulatum, and R. viscosum in the narrow sense. In addition, minor varieties and forms have been described. Because correlated or geographically coherent sets of character states cannot be discerned within this species, infraspecific taxa are not recognized here (K. A. Kron 1993). Rhododendron viscosum is most closely related to R. arborescens, and possibly also R. atlanticum. Hybrids with R. cumberlandense and R. arborescens are known. Plants with white corollas and a yellow blotch may be the result of hybridization.

(Discussion copyrighted by Flora of North America; reprinted with permission.)

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.)

Source FNA vol. 8, p. 471. FNA vol. 8, p. 467.
Parent taxa Ericaceae > subfam. Ericoideae > Rhododendron Ericaceae > subfam. Ericoideae > Rhododendron
Sibling taxa
R. alabamense, R. albiflorum, R. arborescens, R. atlanticum, R. austrinum, R. calendulaceum, R. canadense, R. canescens, R. catawbiense, R. columbianum, R. cumberlandense, R. eastmanii, R. flammeum, R. groenlandicum, R. lapponicum, R. macrophyllum, R. maximum, R. minus, R. occidentale, R. periclymenoides, R. prinophyllum, R. prunifolium, R. tomentosum, R. vaseyi
R. albiflorum, R. arborescens, R. atlanticum, R. austrinum, R. calendulaceum, R. canadense, R. canescens, R. catawbiense, R. columbianum, R. cumberlandense, R. eastmanii, R. flammeum, R. groenlandicum, R. lapponicum, R. macrophyllum, R. maximum, R. minus, R. occidentale, R. periclymenoides, R. prinophyllum, R. prunifolium, R. tomentosum, R. vaseyi, R. viscosum
Synonyms Azalea viscosa, Azalea oblongifolia, Azalea serrulata, R. coryi, R. oblongifolium, R. serrulatum, R. viscosum var. serrulatum Azalea alabamensis
Name authority (Linnaeus) Torrey: Fl. N. Middle United States, 424. 1824 , Rehder: in E. H. Wilson and A. J. Rehder, Monogr. Azaleas, 141. 1921 ,
Web links