8.
Rhododendron catawbiense
Michaux, Fl. Bor.-Amer. 1: 258. 1803.
Mountain rosebay, purple laurel
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.
2
n
= 26.
Flowering spring. Rocky slopes, ridges, and balds; 50-2000 m; Ala., Ga., Ky., N.C., S.C., Tenn., Va., W.Va.
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.
