Rhododendron catawbiense

Michaux

Fl. Bor.-Amer. 1: 258. 1803,.

Common names: Mountain rosebay purple laurel
Endemic
Treatment appears in FNA Volume 8. Treatment on page 463. Mentioned on page 456, 462.

Shrubs or trees, to 3.5 (–6) m, sometimes rhizomatous. Stems: bark smooth to vertically furrowed, shredding; twigs multicellular eglandular-hairy (hairs branched basally, crisp/matted), glabrate in age. Leaves persistent; petiole multicellular-hairy (hairs ± branched), often glabrescent; blade elliptic to obovate or slightly ovate, (5–) 6–12 (–17) × (2.5–) 3.5–6 (–7.7) cm (length/width ratio 1.3–3.5), thick, coriaceous, margins entire, revolute to plane, glabrous or sparsely hairy along margins (hairs branched, ephemeral), apex rounded/mucronate to obtuse or acute, surfaces sparsely eglandular-hairy (hairs basally branched, crisped, quickly deciduous), abaxial surface minutely, obscurely papillose. Floral bud-scales multicellular stipitate-glandular-hairy, eglandular-hairy (hairs basally branched, crisped), and unicellular-hairy (hairs short-to-elongate), margins eglandular-hairy (hairs branched). Inflorescences 12–20-flowered; bracts similar to bud-scales. Pedicels 10–50 mm, sparsely to moderately multicellular eglandular-hairy (hairs ferruginous, branched, crisped), glabrate in age. Flowers opening after development of leaves (of flowering shoots), erect to horizontal, fragrant; calyx lobes 0.5–1.7 mm, glabrous or eglandular-hairy; corolla deep pink to purple, rarely white, usually with yellowish-green spots on upper lobe, campanulate, 27–50 mm, glabrous on outer surface, petals connate, lobes 15–30 mm, tube gradually expanding into lobes, 12–28 mm; stamens 10, included, ± unequal, 19–39 mm; (ovary multicellular eglandular-hairy). Capsules borne on erect pedicels, 10–23 × 3.5–7 mm, eglandular-hairy (hairs ferruginous, branched). Seeds without distinct tails, flattened portion of testa well developed at each end; testa expanded, dorsiventrally flattened, loose. 2n = 26.


Phenology: Flowering spring.
Habitat: Rocky slopes, ridges, and balds
Elevation: 50-2000 m

Distribution

V8 906-distribution-map.gif

Ala., Ga., Ky., N.C., S.C., Tenn., Va., W.Va.

Discussion

Large-flowered, large-leaved plants of Rhododendron catawbiense from eastern North Carolina have been named forma insularis Coker. Rare hybrids with R. maximum have been reported by A. E. Radford et al. (1968) (R. ×wellesleyanum Waterer ex Rehder); we have seen no specimens.

Selected References

None.

Lower Taxa

None.

... more about "Rhododendron catawbiense"
Walter S. Judd +  and Kathleen A. Kron +
Michaux +
smooth +  and vertically furrowed +
not flaky +
12 cm120 mm <br />0.12 m <br /> (17 cm170 mm <br />0.17 m <br />) +
6 cm60 mm <br />0.06 m <br /> (7.7 cm77 mm <br />0.077 m <br />) +
6 cm60 mm <br />0.06 m <br /> (12 cm120 mm <br />0.12 m <br />) +
elliptic;obovate or slightly ovate +
coriaceous +
thick;3.5cm;6cm +
scale-like +
eglandular-hairy +  and glabrous +
0.05 cm0.5 mm <br />5.0e-4 m <br /> (0.17 cm1.7 mm <br />0.0017 m <br />) +
1 cm10 mm <br />0.01 m <br /> (2.3 cm23 mm <br />0.023 m <br />) +
eglandular-hairy +
0.35 cm3.5 mm <br />0.0035 m <br /> (0.7 cm7 mm <br />0.007 m <br />) +
Mountain rosebay +  and purple laurel +
yellowish-green spots +, white +, pink +  and purple +
rotate to crateriform campanulate cylindric globose or urceolate +
2.7 cm27 mm <br />0.027 m <br /> (5 cm50 mm <br />0.05 m <br />) +
Ala. +, Ga. +, Ky. +, N.C. +, S.C. +, Tenn. +, Va. +  and W.Va. +
50-2000 m +
undifferentiated +
fusiform +
unicellular-hairy +, eglandular-hairy +  and stipitate-glandular-hairy +
erect;horizontal +
fragrant +
pendulous +  and erect +
usually ovoid;cylindric +
Rocky slopes, ridges, and balds +
multicellular +
terminal +  and axillary +
persistent +
15mm +  and 30mm +
eglandular-hairy +, hairy +  and glabrous +
revolute;plane +
parietal +, axile +  and placentation +
tenuinucellate +  and unitegmic +
multicellular +
glabrate +  and eglandular-hairy +
1 cm10 mm <br />0.01 m <br /> (5 cm50 mm <br />0.05 m <br />) +
scale-like +
reduced +
not sticky +
glabrescent +  and multicellular-hairy +
Flowering spring. +
4-5-carpellate +
Fl. Bor.-Amer. +
distinct +
tailed +, flattened-ellipsoidal +  and fusiform +
unequal +
procumbent +  and prostrate +
creeping +  and sprawling +
peltate +  and capitate +
straight +
eglandular-hairy +
Undefined tribe Empetraceae +
distinct +
Rhododendron catawbiense +
Rhododendron +
species +
flattened +
expanded +
expanding +
1.2 cm12 mm <br />0.012 m <br /> (2.8 cm28 mm <br />0.028 m <br />) +
multicellular +
glabrate +  and eglandular-hairy +
evergreen +, deciduous +  and perennial +
tree +  and shrub +
heterotrophic +, autotrophic +  and mycotrophic +