Rhododendron viscosum

(Linnaeus) Torrey

Fl. N. Middle United States, 424. 1824 ,.

Common names: Swamp or clammy azalea
IllustratedEndemic
Basionyms: Azalea viscosa Linnaeus Sp. Pl. 1: 151. 1753
Synonyms: Azalea oblongifolia Small Azalea serrulata Small Rhododendron coryi Shinners Rhododendron oblongifolium (Small) Millais Rhododendron serrulatum (Small) Millais Rhododendron viscosum var. serrulatum (Small) H. E. Ahles
Treatment appears in FNA Volume 8. Treatment on page 471. Mentioned on page 458, 468.

Shrubs or trees, to 7 m, rhizomatous or not. Stems: bark smooth to vertically furrowed, shredding; twigs sparsely to conspicuously multicellular eglandular-hairy (hairs unbranched), otherwise glabrous or densely 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. 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. Inflorescences 3–14-flowered; bracts similar to bud-scales. Pedicels 5–27 mm, stipitate-glandular or, sometimes, eglandular-hairy, otherwise sparsely to densely 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. Capsules borne on erect pedicels, 7–20 × 3–7 mm, usually densely stipitate-glandular and/or eglandular-hairy, otherwise densely unicellular-hairy to ± glabrous. Seeds without distinct tails, flattened portion of testa well developed at each end; testa expanded, dorsiventrally flattened, ± loose. 2n = 26.


Phenology: Flowering spring–summer.
Habitat: Acid swamps, bogs, seepage slopes, pocosins, streamheads and baygalls, wet pine flatwoods, moist pine or pine/oak forests, hummocks, shrub balds
Elevation: 0-1500 m

Distribution

V8 922-distribution-map.gif

Ala., Ark., Conn., Del., Fla., Ga., La., Maine, Md., Mass., Miss., N.H., N.J., N.Y., N.C., Okla., Pa., R.I., S.C., Tenn., Tex., Vt., Va.

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.

Selected References

None.

Lower Taxa

None.

... more about "Rhododendron viscosum"
unicellular-hairy +  and glabrous +
unicellular-hairy +, eglandular-hairy +, scattered +  and glabrous +
Mucronate (?) +, Acute (?) +  and Obtuse (?) +
Walter S. Judd +  and Kathleen A. Kron +
(Linnaeus) Torrey +
smooth +  and vertically furrowed +
not flaky +
Azalea viscosa +
7 cm70 mm <br />0.07 m <br /> (9 cm90 mm <br />0.09 m <br />) +
3 cm30 mm <br />0.03 m <br /> (3.8 cm38 mm <br />0.038 m <br />) +
2 cm20 mm <br />0.02 m <br /> (7 cm70 mm <br />0.07 m <br />) +
ovate;obovate +
membranous;chartaceous +
thin;1cm;3cm +
scale-like +
0.05 cm0.5 mm <br />5.0e-4 m <br /> (0.5 cm5 mm <br />0.005 m <br />) +
0.7 cm7 mm <br />0.007 m <br /> (2 cm20 mm <br />0.02 m <br />) +
otherwise densely unicellular-hairy +  and more or less glabrous +
0.3 cm3 mm <br />0.003 m <br /> (0.7 cm7 mm <br />0.007 m <br />) +
Swamp or clammy azalea +
pink +, pink-tinged +  and white +
unicellular-hairy +  and stipitate-glandular-hairy +
rotate to crateriform campanulate cylindric globose or urceolate +
2 cm20 mm <br />0.02 m <br /> (5.8 cm58 mm <br />0.058 m <br />) +
Ala. +, Ark. +, Conn. +, Del. +, Fla. +, Ga. +, La. +, Maine +, Md. +, Mass. +, Miss. +, N.H. +, N.J. +, N.Y. +, N.C. +, Okla. +, Pa. +, R.I. +, S.C. +, Tenn. +, Tex. +, Vt. +  and Va. +
0-1500 m +
undifferentiated +
fusiform +
unicellular-hairy +  and glabrous +
fragrant +
erect +  and horizontal +
usually ovoid;cylindric +
Acid swamps, bogs, seepage slopes, pocosins, streamheads and baygalls, wet pine flatwoods, moist pine or pine/oak forests, hummocks, shrub balds +
multicellular +
terminal +  and axillary +
deciduous +
7mm +  and 21mm +
, +, unicellular-ciliate +  and ciliate +
glandular-serrulate +, serrulate +, , +  and entire +
unicellular-hairy +, eglandular-hairy +  and stipitate-glandular-hairy +
parietal +, axile +  and placentation +
tenuinucellate +  and unitegmic +
unicellular-hairy +, eglandular-hairy +, , +  and stipitate-glandular +
0.5 cm5 mm <br />0.005 m <br /> (2.7 cm27 mm <br />0.027 m <br />) +
scale-like +
reduced +
not sticky +
multicellular +
unicellular-hairy +  and eglandular-hairy +
Flowering spring–summer. +
4-5-carpellate +
Fl. N. Middle United States, +
distinct +
tailed +, flattened-ellipsoidal +  and fusiform +
Illustrated +  and Endemic +
unequal +
procumbent +  and prostrate +
creeping +  and sprawling +
peltate +  and capitate +
straight +
unicellular-hairy +, eglandular-hairy +, , +  and stipitate-glandular-hairy +
Azalea oblongifolia +, Azalea serrulata +, Rhododendron coryi +, Rhododendron oblongifolium +, Rhododendron serrulatum +  and Rhododendron viscosum var. serrulatum +
distinct +
Rhododendron viscosum +
Rhododendron +
species +
flattened +
expanded +
expanded +
1.3 cm13 mm <br />0.013 m <br /> (3.7 cm37 mm <br />0.037 m <br />) +
multicellular +
unicellular-hairy +, glabrous +  and eglandular-hairy +
rhizomatous +  and not +
evergreen +, deciduous +  and perennial +
tree +  and shrub +
heterotrophic +, autotrophic +  and mycotrophic +