Rhododendron tomentosum

Harmaja

Ann. Bot. Fenn. 27: 204. 1990,.

Common names: Labrador or trappers tea
Basionyms: Ledum palustre Linnaeus Sp. Pl. 1: 391. 1753,
Synonyms: Ledum decumbens (Aiton) Loddiges ex Steudel Ledum palustre subsp. decumbens (Aiton) Hultén Rhododendron subarcticum Harmaja Rhododendron tolmachevii Rhododendron tomentosum subsp. decumbens (Aiton) Elven & D. F. Murray Rhododendron tomentosum var. subarcticum (Harmaja) G. D. Wallace
Treatment appears in FNA Volume 8. Treatment on page 459. Mentioned on page 455, 457, 460, 462.

Shrubs, to 0.5 m, 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. 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. Floral bud-scales with lepidote scales and unicellular-hairy abaxially, margins unicellular-hairy. Inflorescences slightly rounded, 10–35-flowered; bracts lepidote abaxially, margins ciliate, long-crisped-hairy, sometimes also unicellular-hairy. 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. 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. 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. Seeds somewhat elongated beyond narrow ends; testa closely appressed. 2n = 26, 52.


Phenology: Flowering spring–summer.
Habitat: Bogs, muskeg, tundra, raised beach ridges
Elevation: 0-1800 m

Distribution

V8 898-distribution-map.gif

Greenland, Alta., B.C., Man., Nfld. and Labr. (Nfld.), N.W.T., Nunavut, Ont., Que., Sask., Yukon, Alaska, Europe, Asia

Discussion

Selected References

None.

Lower Taxa

None.

"broad" is not a number."elongated" is not a number.

... more about "Rhododendron tomentosum"
Walter S. Judd +  and Kathleen A. Kron +
Harmaja +
furrowed +  and smooth +
not flaky +
Ledum palustre +
2 cm20 mm <br />0.02 m <br /> (5 cm50 mm <br />0.05 m <br />) +
acicular;plane +
coriaceous +
1cm;4cm +
scale-like +
1 cm10 mm <br />0.01 m <br /> (?) +
0.25 cm2.5 mm <br />0.0025 m <br /> (0.5 cm5 mm <br />0.005 m <br />) +
0.1 cm1 mm <br />0.001 m <br /> (0.3 cm3 mm <br />0.003 m <br />) +
Labrador or trappers tea +
white +  and cream +
rotate to crateriform campanulate cylindric globose or urceolate +
0.2 cm2 mm <br />0.002 m <br /> (0.8 cm8 mm <br />0.008 m <br />) +
Greenland +, Alta. +, B.C. +, Man. +, Nfld. and Labr. (Nfld.) +, N.W.T. +, Nunavut +, Ont. +, Que. +, Sask. +, Yukon +, Alaska +, Europe +  and Asia +
0-1800 m +
undifferentiated +
fusiform +
not fragrant +
usually ovoid;cylindric +
Bogs, muskeg, tundra, raised beach ridges +
unicellular +  and multicellular +
white +  and ferruginous +
long-crisped +
terminal +  and axillary +
unicellular-hairy +
persistent +
connate +  and distinct +
unicellular-hairy +, long-crisped-hairy +  and glabrous +
revolute;plane;toothed;entire;revolute;plane;toothed;entire +
stipitate-glandular-hairy +  and unicellular-hairy +
parietal +, axile +  and placentation +
tenuinucellate +  and unitegmic +
multicellular +  and long-stalked +
glandular-hairy +  and eglandular-hairy +
0.5 cm5 mm <br />0.005 m <br /> (2.6 cm26 mm <br />0.026 m <br />) +
scale-like +
reduced +
0.5 cm5 mm <br />0.005 m <br /> (0.7 cm7 mm <br />0.007 m <br />) +
not sticky +
Flowering spring–summer. +
4-5-carpellate +
Ann. Bot. Fenn. +
peltate +, unicellular +  and glandular-peltate +
ferruginous +
long-crisped +
distinct +
tailed +, flattened-ellipsoidal +  and fusiform +
procumbent +  and prostrate +
prostrate +  and creeping +
peltate +  and capitate +
straight +
Ledum decumbens +, Ledum palustre subsp. decumbens +, Rhododendron subarcticum +, Rhododendron tolmachevii +, Rhododendron tomentosum subsp. decumbens +  and Rhododendron tomentosum var. subarcticum +
Rhododendron tomentosum +
Rhododendron +
species +
unicellular-hairy +
evergreen +, deciduous +  and perennial +
heterotrophic +, autotrophic +  and mycotrophic +