Rhododendron austrinum

(Small) Rehder in L. H. Bailey

in L. H. Bailey, Stand. Cycl. Hort. 6: 3571. 1917 ,.

Common names: Florida azalea
Endemic
Basionyms: Azalea austrina Small Fl. S.E. U.S. ed. 2, 1356. 1913
Treatment appears in FNA Volume 8. Treatment on page 466. Mentioned on page 458, 467, 469.

Shrubs or trees, to 3 (–5) m, usually not rhizomatous. Stems: bark smooth to vertically furrowed, shredding; twigs conspicuously multicellular stipitate-glandular-hairy, otherwise ± moderately to densely unicellular-hairy. Leaves deciduous; petiole multicellular stipitate-glandular-hairy and unicellular-hairy; blade ovate to obovate, 3–11 × 1.5–4.5 cm, thin, membranous, margins entire, plane, ciliate, eglandular and stipitate-glandular-hairy, apex acute to obtuse, often mucronate, abaxial surface ± moderately unicellular-hairy, adaxial surface sparsely scattered stipitate-glandular-hairy, otherwise ± moderately unicellular-hairy, rarely glabrescent. Floral bud-scales densely to moderately unicellular-hairy abaxially, margins unicellular-ciliate, also partly glandular-serrate. Inflorescences 9–24-flowered; bracts similar to bud-scales. Pedicels 5–17 mm, stipitate-glandular-hairy, otherwise ± densely unicellular-hairy. Flowers opening before or with leaves, erect to horizontal, slightly or not fragrant; calyx lobes 0.5–2.5 mm, scattered stipitate-glandular-hairy, otherwise unicellular-hairy, margins long stipitate-glandular-hairy; corolla yellow to orange, with usually red or orange-red tube, with indistinct, darker yellow, orange, or red blotch on upper lobe, funnelform, 25–45 mm, scattered stipitate-glandular-hairy, otherwise ± moderately unicellular-hairy on outer surface, petals connate, lobes 9–20 mm, tube ± gradually expanded into lobes, 15–25 mm (longer than lobes); stamens 5, much exserted, ± unequal, 52–77 mm. Capsules borne on erect pedicels, 14–26 × 3–5.5 mm, sparsely to densely stipitate-glandular-hairy, otherwise moderately to densely unicellular-hairy. Seeds without distinct tails, flattened portion of testa well developed at each end; testa expanded, dorsiventrally flattened, ± loose. 2n = 26.


Phenology: Flowering spring.
Habitat: Wooded slopes, bluffs or lowlands along streams
Elevation: 0-100 m

Discussion

Rhododendron austrinum is most closely related to R. luteum Sweet of eastern Europe, Turkey, and the Caucasus region and to R. occidentale (K. A. Kron 1993).

Selected References

None.

Lower Taxa

None.

... more about "Rhododendron austrinum"
unicellular-hairy +
glabrescent +, unicellular-hairy +  and stipitate-glandular-hairy +
Mucronate (?) +, Acute (?) +  and Obtuse (?) +
Walter S. Judd +  and Kathleen A. Kron +
(Small) Rehder in L. H. Bailey +
smooth +  and vertically furrowed +
not flaky +
Azalea austrina +
3 cm30 mm <br />0.03 m <br /> (11 cm110 mm <br />0.11 m <br />) +
ovate;obovate +
membranous +
thin;1.5cm;4.5cm +
red +, orange +  and darker yellow +
scale-like +
unicellular-hairy +  and stipitate-glandular-hairy +
0.05 cm0.5 mm <br />5.0e-4 m <br /> (0.25 cm2.5 mm <br />0.0025 m <br />) +
1.4 cm14 mm <br />0.014 m <br /> (2.6 cm26 mm <br />0.026 m <br />) +
unicellular-hairy +  and stipitate-glandular-hairy +
0.3 cm3 mm <br />0.003 m <br /> (0.55 cm5.5 mm <br />0.0055 m <br />) +
Florida azalea +
yellow +  and orange +
unicellular-hairy +  and stipitate-glandular-hairy +
rotate to crateriform campanulate cylindric globose or urceolate +
2.5 cm25 mm <br />0.025 m <br /> (4.5 cm45 mm <br />0.045 m <br />) +
Ala. +, Fla. +, Ga. +  and Miss. +
0-100 m +
undifferentiated +
fusiform +
pendulous +  and erect +
usually ovoid;cylindric +
Wooded slopes, bluffs or lowlands along streams +
multicellular +
terminal +  and axillary +
deciduous +
not fragrant +
9mm +  and 20mm +
unicellular-ciliate +  and ciliate +
glandular-serrate +  and entire +
stipitate-glandular-hairy +
parietal +, axile +  and placentation +
tenuinucellate +  and unitegmic +
unicellular-hairy +  and stipitate-glandular-hairy +
0.5 cm5 mm <br />0.005 m <br /> (1.7 cm17 mm <br />0.017 m <br />) +
scale-like +
reduced +
not sticky +
multicellular +
unicellular-hairy +  and stipitate-glandular-hairy +
Flowering spring. +
4-5-carpellate +
in L. H. Bailey, Stand. Cycl. Hort. +
distinct +
tailed +, flattened-ellipsoidal +  and fusiform +
unequal +
procumbent +  and prostrate +
creeping +  and sprawling +
peltate +  and capitate +
straight +
Undefined tribe Empetraceae +
distinct +
Rhododendron austrinum +
Rhododendron +
species +
flattened +
expanded +
orange-red +  and red +
expanded +
1.5 cm15 mm <br />0.015 m <br /> (2.5 cm25 mm <br />0.025 m <br />) +
multicellular +
unicellular-hairy +  and stipitate-glandular-hairy +
evergreen +, deciduous +  and perennial +
tree +  and shrub +
heterotrophic +, autotrophic +  and mycotrophic +