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

early azalea, election-pink, hoary azalea, roseshell azalea

coastal azalea, dwarf azalea

Habit Shrubs, to 3(–5) m, usually not rhizomatous. Shrubs, to 0.5–1 m, very strongly rhizomatous.
Stems

bark smooth to vertically furrowed, shredding;

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

bark ± smooth, not shredding;

twigs scattered, multicellular eglandular-hairy (hairs unbranched) and/or stipitate-glandular-hairy, otherwise glabrous or, sometimes, sparsely unicellular-hairy.

Leaves

deciduous;

petiole usually multicellular eglandular-hairy and unicellular-hairy;

blade ovate to obovate, 3–9 × 1.2–3.7 cm, thin, membranous, margins entire, plane, conspicuously ciliate, eglandular-hairy (hairs ascending away from margins), apex acute to obtuse, often mucronate, abaxial surface sparsely to densely unicellular-hairy, sometimes also eglandular-hairy, adaxial surface usually sparsely unicellular-hairy, sometimes glabrous, often also scattered eglandular-hairy.

deciduous;

petiole multicellular eglandular- and/or stipitate-glandular-hairy, sometimes also unicellular-hairy;

blade ovate to obovate, 2–5.5(–6.5) × 0.8–2(–3) cm, thin, membranous to chartaceous, margins entire, plane, ciliate, eglandular-hairy, apex acute to obtuse, often mucronate, abaxial surface glabrous or, rarely, sparsely scattered eglandular-hairy, sometimes sparsely (rarely densely) unicellular-hairy, adaxial surface (lustrous to dull), glabrous or sparsely scattered stipitate-glandular-hairy, sometimes also sparsely unicellular-hairy.

Inflorescences

4–13-flowered;

bracts similar to bud scales.

4–13-flowered;

bracts similar to bud scales.

Pedicels

5–26 mm, usually stipitate-glandular-hairy, or, sometimes, also eglandular-hairy, otherwise sparsely to moderately unicellular-hairy.

4–15(–20) mm, eglandular- and/or stipitate-glandular-hairy, otherwise glabrous or sparsely (rarely moderately) unicellular-hairy.

Flowers

opening before or with leaves, erect to horizontal, fragrant (spicy-scented);

calyx lobes 0.5–4 mm, surfaces and margins scattered stipitate-glandular- and/or eglandular-hairy, otherwise sparsely to densely unicellular-hairy;

corolla usually bright pink, without blotch on upper lobe, funnelform, 25–45 mm, scattered, multicellular stipitate-glandular-hairy (hairs not forming distinct lines), otherwise sparsely to moderately unicellular-hairy on outer surface, petals connate, lobes 10–23 mm, tube gradually expanded into lobes, 11–27 mm (equaling or longer than lobes);

stamens 5, much exserted, ± unequal, 32–53 mm.

opening before or with leaves, erect to horizontal, usually very fragrant and/or nearly mephitic-scented;

calyx lobes 0.7–5.5(–10) mm, marginal and scattered stipitate-glandular- or, less commonly, eglandular-hairy, sometimes also unicellular-hairy;

corolla white, usually flushed pink or rose (especially on tube), without blotch on upper lobe, funnelform, 23–58 mm, scattered, usually conspicuous, multicellular stipitate-glandular-hairy (hairs forming prominent band along middle of each lobe), otherwise glabrous or, sometimes, sparsely unicellular-hairy on outer surface, petals connate, lobes 8–24 mm, tube rather gradually expanded into lobes, 16–35 mm (equaling or longer than lobes);

stamens 5, much exserted, ± unequal, 32–63 mm.

Capsules

borne on erect pedicel, 10–28 × 3–7 mm, stipitate-glandular-hairy, otherwise sparsely unicellular-hairy.

borne on erect pedicels, 10–24 × 4–8 mm, usually densely stipitate-glandular-hairy, otherwise glabrous or densely unicellular-hairy.

Seeds

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

testa expanded, dorsiventrally flattened, ± loose.

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

testa expanded, dorsiventrally flattened, ± loose.

Floral

bud scales very sparsely to densely unicellular-hairy abaxially, especially near midvein, margins unicellular-ciliate.

bud scales glabrous or densely unicellular-hairy abaxially, margins usually unicellular-ciliate.

2n

= 26.

= 26.

Rhododendron prinophyllum

Rhododendron atlanticum

Phenology Flowering spring. Flowering spring.
Habitat Acidic thickets or bogs, swampy to dry, rocky woods, bluffs, ravines, or along streams Moist pine flatwoods and savannas, sometimes in drier pine and/or oak forests, primarily in fire-maintained communities of the Atlantic coastal plain
Elevation 100-1500 m (300-4900 ft) 0-200 m (0-700 ft)
Distribution
from FNA
AL; AR; CT; IL; KY; MA; MD; MO; NC; NH; NJ; NY; OH; OK; PA; RI; TN; TX; VA; VT; WV
[WildflowerSearch map]
[BONAP county map]
from FNA
DE; GA; MD; NC; PA; SC; VA
[WildflowerSearch map]
[BONAP county map]
Discussion

Rhododendron prinophyllum is unusual in its strongly disjunct distribution. Plants in the western portion of the range often have longer corolla tubes and are most similar to R. canescens and R. periclymenoides, and can be distinguished from both by their broader, more gradually expanded corolla tubes and usually consistently glandular sepal margins, pedicels, and ovaries. Hybrids are known with R. calendulaceum and R. periclymenoides. The name R. roseum (Loiseleur) Rehder, which has been used for this species, is illegitimate because it was superfluous when published (K. A. Kron 1989).

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

Varieties and forms have been described within Rhododendron atlanticum (see E. H. Wilson and A. J. Rehder 1921; K. A. Kron 1993). Hybrids between it and R. canescens and R. periclymenoides are known. Rhododendron atlanticum is easily confused with the sympatric R. viscosum, which generally is taller, less rhizomatous, hairier, larger-leaved, and later-flowering (i.e., flowers appear after the leaves have expanded).

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

Source FNA vol. 8, p. 469. FNA vol. 8, p. 468.
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. prunifolium, R. tomentosum, R. vaseyi, R. viscosum
R. alabamense, R. albiflorum, R. arborescens, 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 prinophylla Azalea atlantica
Name authority (Small) Millais: Rhododendrons, 229. 1917 , (Ashe) Rehder: in E. H. Wilson and A. J. Rehder, Monogr. Azaleas, 147. 1921 ,
Web links