Rhododendron tomentosum |
Rhododendron periclymenoides |
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Labrador tea, marsh Labrador tea, northern Labrador tea, trappers tea |
election-pink, pink azalea, pinxter-flower, pinxterbloom azalea |
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Habit | Shrubs, to 0.5 m, rhizomatous. | Shrubs, to 3(–5) m, usually not rhizomatous. |
Stems | creeping or prostrate; bark ± smooth; twigs unicellular-hairy and with flattened, glandular scales, scales often obscured by dense, ferruginous, long-crisped, multicellular hairs. |
bark smooth to vertically furrowed, shredding; twigs scattered, multicellular eglandular-hairy (hairs unbranched) or such hairs ± absent, otherwise glabrous or sparsely unicellular-hairy. |
Leaves | persistent, (fragrant when crushed); petiole with unicellular and/or peltate scales and, sometimes, ferruginous, long-crisped hairs; blade ± linear, 2–5 × 1–4 cm (often much longer than wide), coriaceous, margins entire, revolute, glabrous, apex acute, abaxial surface with sparse to dense, glandular-peltate scales without broad rim, scales often obscured by dense (to sparse), ferruginous, long-crisped, multicellular hairs sometimes forming dense, ± uniform mat, adaxial surface rugose with scattered, lepidote scales and sometimes also with white, unicellular hairs along impressed midrib, midrib usually lanate. |
deciduous; petiole multicellular eglandular-hairy and unicellular-hairy; blade ovate to obovate, 3–9(–12.5) × 1.4–3.8(–5) cm, thin, membranous, margins entire, plane, ciliate, eglandular-hairy, often strikingly so, apex acute to obtuse, often mucronate, abaxial surface often glabrous or, sometimes, sparsely unicellular-hairy, sometimes sparsely eglandular-hairy, adaxial surface sometimes scattered eglandular-hairy, otherwise glabrous or, sometimes, sparsely unicellular-hairy. |
Inflorescences | slightly rounded, 10–35-flowered; bracts lepidote abaxially, margins ciliate, long-crisped-hairy, sometimes also unicellular-hairy. |
6–15-flowered; bracts similar to bud scales. |
Pedicels | 5–26 mm, sparsely eglandular-hairy (hairs ferruginous, elongated), with ferruginous, long-crisped, unicellular and/or peltate scales, sometimes also long-stalked, multicellular glandular-hairy. |
4–19 mm, eglandular-hairy, otherwise glabrous or sparsely unicellular-hairy. |
Flowers | radially symmetric, opening after leaves (of flowering shoots), ± erect, not fragrant; calyx lobes ca. 1 mm, outer surface densely to sparsely unicellular-hairy (hairs tan), and multicellular, stipitate-glandular-hairy (hairs red) on margins; corolla white to cream, without blotch, ± rotate, 2–8 mm, inner surface often densely unicellular-hairy, petals appearing distinct or only slightly connate basally, lobes 5–7 mm; stamens 10, exserted, ± equal, 4.4–8.5 mm. |
opening before or with leaves, erect to horizontal, slightly fragrant; calyx lobes 0.5–2.5(–4) mm, surfaces and margins scattered, eglandular- and/or, rarely, stipitate-glandular-hairy, otherwise glabrous or moderately unicellular-hairy; corolla deep pink to white with pink tube, without blotch on upper lobe, funnelform, 23–45 mm, scattered, multicellular eglandular-hairy and/or, less commonly, multicellular stipitate-glandular-hairy (hairs not forming distinct lines), otherwise sparsely to moderately unicellular-hairy on outer surface, petals connate, lobes 9–25 mm, tube usually gradually expanded into lobes, 12–27 mm (equaling or longer than lobes); stamens 5, much exserted, ± unequal, 32–68 mm. |
Capsules | borne on apex of sharply recurved pedicels, 2.5–5 × 1–3 mm (only slightly longer than wide), with sparse to dense, lepidote scales, acropetally dehiscent. |
borne on erect pedicels, 10–30 × 3–6.5 mm, eglandular-hairy, otherwise glabrous or sparsely unicellular-hairy. |
Seeds | somewhat elongated beyond narrow ends; testa closely appressed. |
without distinct tails; testa rather close, but ± loose. |
Floral | bud scales with lepidote scales and unicellular-hairy abaxially, margins unicellular-hairy. |
bud scales usually glabrous abaxially, margins unicellular-ciliate. |
2n | = 26, 52. |
= 26. |
Rhododendron tomentosum |
Rhododendron periclymenoides |
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Phenology | Flowering spring–summer. | Flowering spring. |
Habitat | Bogs, muskeg, tundra, raised beach ridges | Mixed, dry to moist woods, often along streams, thickets, swamps |
Elevation | 0-1800 m (0-5900 ft) | 0-1000 m (0-3300 ft) |
Distribution |
AK; AB; BC; MB; NF; NT; NU; ON; QC; SK; YT; Greenland; Europe; Asia
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AL; CT; DE; GA; KY; MA; MD; NC; NJ; NY; OH; PA; RI; SC; TN; VA; VT; WV
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Discussion | Rhododendron periclymenoides is most similar to R. canescens, from which it can be distinguished by its less hairy leaves and bud scales, more gradually expanded corolla tube, and usually eglandular corolla indumentum; plants with stipitate-glandular hairs on the corolla occur sporadically throughout the range of this species (K. A. Kron 1993). Occasional hybridization with R. atlanticum, R. canescens, and R. prinophyllum probably occurs. The name R. nudiflorum Torrey has been incorrectly applied to this species; that name was superfluous when published and applies to R. luteum. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
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Source | FNA vol. 8, p. 459. | FNA vol. 8, p. 468. |
Parent taxa | Ericaceae > subfam. Ericoideae > Rhododendron | Ericaceae > subfam. Ericoideae > Rhododendron |
Sibling taxa | ||
Synonyms | Ledum palustre, Ledum decumbens, Ledum palustre subsp. decumbens, R. subarcticum, R. tolmachevii, R. tomentosum subsp. decumbens, R. tomentosum var. subarcticum | Azalea periclymenoides |
Name authority | Harmaja: Ann. Bot. Fenn. 27: 204. (1990) | (Michaux) Shinners: Castanea 27: 95. 1962 , |
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