Rhododendron occidentale

(Torrey & A. Gray) A. Gray in W. H. Brewer et al.

in W. H. Brewer et al., Bot. California 1: 458. 1876 ,.

Common names: Western azalea
Endemic
Basionyms: Azalea occidentalis Torrey & A. Gray in War Department [U.S.], Pacif. Railr. Rep. 4(5): 116. 1857
Synonyms: Azalea californica Torrey & A. Gray ex Durand Rhododendron occidentale var. paludosum Jepson Rhododendron sonomense
Treatment appears in FNA Volume 8. Treatment on page 467. Mentioned on page 458, 468.

Shrubs or trees, to 8 (–10) m, usually not rhizomatous. Stems: bark smooth to vertically furrowed, shredding; twigs sparsely to densely multicellular stipitate-glandular-hairy or unicellular-hairy, or glabrous, sometimes only unicellular-hairy. Leaves deciduous; petiole multicellular eglandular or stipitate-glandular-hairy and unicellular-hairy; blade ovate or obovate to elliptic, (2.5–) 3.5–8.2 (–10.8) × 1.2–2.9 (–3.6) cm, thin, membranous, margins entire, plane, ciliate, eglandular-hairy, sometimes also stipitate-glandular-hairy, apex acute to obtuse, often mucronate, abaxial surface glabrous or sparsely unicellular-hairy, often also stipitate-glandular-hairy (or, rarely, stipitate-glandular and eglandular-hairy), adaxial surface sparsely scattered, multicellular eglandular and/or stipitate-glandular-hairy and unicellular-hairy, or glabrous. Floral bud-scales sparsely to densely unicellular-hairy abaxially, rarely also sparsely eglandular or stipitate-glandular-hairy, margins unicellular-ciliate, or with glands and cilia mixed, or glandular. Inflorescences 3–15-flowered; bracts similar to bud-scales. Pedicels 9–26 mm, stipitate-glandular and, sometimes, also eglandular-hairy. Flowers opening with leaves or after they have expanded, erect to horizontal, fragrant or mephitic-scented; calyx lobes 1–4 (–9) mm, often stipitate-glandular and/or eglandular-hairy, sometimes also unicellular-hairy, margins usually stipitate-glandular-hairy; corolla white with contrasting yellow blotch on upper lobe, white and pink or salmon, or pink with orange blotch on upper lobe, rarely white with yellow lines at throat, or with tube white to red, funnelform, 30–58 mm, stipitate-glandular-hairy and, rarely, also eglandular-hairy, otherwise sparsely to moderately unicellular-hairy or these hairs absent on outer surface, petals connate, lobes 13–29 mm, tube gradually expanding into lobes, 15–29 mm (equaling or longer than lobes); stamens 5, much exserted, ± unequal, 40–75 mm. Capsules borne on erect pedicels, 12–22 × 4–14 mm, multicellular stipitate-glandular-hairy, sometimes also eglandular-hairy, otherwise sparsely unicellular-hairy (unicellular hairs rarely absent). Seeds without distinct tails, flattened portion of testa well developed at each end; testa expanded, dorsiventrally flattened, ± loose. 2n = 26.


Phenology: Flowering spring–summer.
Habitat: Moist, wooded slopes and canyon bottoms, along streams, thickets, bogs, serpentine ridges, ocean bluffs
Elevation: 0-2700 m

Discussion

The flowers of Rhododendron occidentale show an exceptional range of variation in color.

Selected References

None.

Lower Taxa

None.

... more about "Rhododendron occidentale"
stipitate-glandular-hairy +, unicellular-hairy +  and glabrous +
eglandular +  and multicellular +
glabrous +, unicellular-hairy +  and stipitate-glandular-hairy +
Mucronate (?) +, Acute (?) +  and Obtuse (?) +
Walter S. Judd +  and Kathleen A. Kron +
(Torrey & A. Gray) A. Gray in W. H. Brewer et al. +
smooth +  and vertically furrowed +
not flaky +
Azalea occidentalis +
8.2 cm82 mm <br />0.082 m <br /> (10.8 cm108 mm <br />0.108 m <br />) +
2.9 cm29 mm <br />0.029 m <br /> (3.6 cm36 mm <br />0.036 m <br />) +
3.5 cm35 mm <br />0.035 m <br /> (8.2 cm82 mm <br />0.082 m <br />) +
obovate;elliptic +
membranous +
thin;1.2cm;2.9cm +
orange +  and yellow +
scale-like +
0.4 cm4 mm <br />0.004 m <br /> (0.9 cm9 mm <br />0.009 m <br />) +
unicellular-hairy +, eglandular-hairy +  and stipitate-glandular +
0.1 cm1 mm <br />0.001 m <br /> (0.4 cm4 mm <br />0.004 m <br />) +
multicellular +
1.2 cm12 mm <br />0.012 m <br /> (2.2 cm22 mm <br />0.022 m <br />) +
unicellular-hairy +, eglandular-hairy +  and stipitate-glandular-hairy +
0.4 cm4 mm <br />0.004 m <br /> (1.4 cm14 mm <br />0.014 m <br />) +
Western azalea +
white +, with orange blotch +, pink +, punct +, white and pink or salmon +, list +  and coloration +
unicellular-hairy +, eglandular-hairy +  and stipitate-glandular-hairy +
rotate to crateriform campanulate cylindric globose or urceolate +
3 cm30 mm <br />0.03 m <br /> (5.8 cm58 mm <br />0.058 m <br />) +
Calif. +  and Oreg. +
0-2700 m +
undifferentiated +
fusiform +
stipitate-glandular-hairy +  and unicellular-hairy +
mephitic-scented +  and fragrant +
erect +  and horizontal +
usually ovoid;cylindric +
Moist, wooded slopes and canyon bottoms, along streams, thickets, bogs, serpentine ridges, ocean bluffs +
multicellular +
terminal +  and axillary +
deciduous +
13mm +  and 29mm +
unicellular-ciliate +  and ciliate +
stipitate-glandular-hairy +  and eglandular-hairy +
parietal +, axile +  and placentation +
tenuinucellate +  and unitegmic +
eglandular-hairy +  and stipitate-glandular +
0.9 cm9 mm <br />0.009 m <br /> (2.6 cm26 mm <br />0.026 m <br />) +
scale-like +
reduced +
not sticky +
eglandular +  and multicellular +
unicellular-hairy +  and stipitate-glandular-hairy +
Flowering spring–summer. +
4-5-carpellate +
in W. H. Brewer et al., Bot. California +
distinct +
tailed +, flattened-ellipsoidal +  and fusiform +
unequal +
procumbent +  and prostrate +
creeping +  and sprawling +
peltate +  and capitate +
straight +
Azalea californica +, Rhododendron occidentale var. paludosum +  and Rhododendron sonomense +
distinct +
Rhododendron occidentale +
Rhododendron +
species +
flattened +
expanded +
white +  and red +
expanding +
1.5 cm15 mm <br />0.015 m <br /> (2.9 cm29 mm <br />0.029 m <br />) +
unicellular-hairy +, glabrous +, stipitate-glandular-hairy +  and multicellular +
evergreen +, deciduous +  and perennial +
tree +  and shrub +
heterotrophic +, autotrophic +  and mycotrophic +