Jepson eFlora: Taxon page
Vascular Plants of California
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Rhododendron macrophyllum

Higher Taxonomy
Family: EricaceaeView DescriptionDichotomous Key
Habit: Perennial herb, shrub, tree. Stem: bark often peeling distinctively. Leaf: simple or 0, generally cauline, alternate, opposite (whorled), evergreen or deciduous, often leathery, petioled or not; stipules 0. Inflorescence: raceme, panicle, cyme, or flowers 1, terminal or axillary, generally bracted; pedicel often with 2 bractlets. Flower: generally bisexual, generally radial, bell-shaped, cylindric, or urn-shaped; sepals generally (0)4--5, generally free; petals generally (0)4--5, free or fused; stamens (2--5)8--10, free, filaments rarely appendaged, anthers dehiscing by pores or slits, awns 0 or 2(4), seemingly abaxial, reduced or elongate, generally curved; nectary generally present at ovary base, generally disk-like; ovary superior or inferior, chambers generally 1--5, placentas axile or parietal, ovules 1--many per chamber, style 1, stigma head- to funnel-like or lobed. Fruit: capsule, drupe, berry. Seed: generally many, winged or not.
Genera In Family: +- 100 genera, 3000 species: generally worldwide except deserts; some cultivated, especially Arbutus, Arctostaphylos, Rhododendron, Vaccinium. Note: Monophyletic only if Empetraceae included, as treated here. Ledum included in Rhododendron. Non-green plants obtain nutrition from green plants through fungal intermediates.
eFlora Treatment Author: Gary D. Wallace, except as noted
Scientific Editor: Gary D. Wallace, Thomas J. Rosatti, Bruce G. Baldwin.
Genus: RhododendronView DescriptionDichotomous Key

Habit: Shrub to tree, glabrous, hairy, and/or with glandular scale-like hairs. Stem: prostrate to erect, bark thin, sometimes peeling or shredding. Leaf: alternate, evergreen or deciduous, ovate to obovate to elliptic, margin entire, flat to rolled under. Inflorescence: raceme, 1--many-flowered, bracts green to red-brown. Flower: sepals, petals generally 5, corolla radial to bilateral, 1--5 cm, petals free to +- fused, spots or blotch present or 0; anther awns 0; ovary superior. Fruit: capsule, septicidal, dehiscing base to tip or tip to base, placentas axile. Seed: many, fusiform, +- flat to not, wings and/or tails present or 0.
Etymology: (Greek: rose tree)
eFlora Treatment Author: Kathleen A. Kron & Walter S. Judd
Unabridged Reference: Chamberlain 1982. Notes Roy. Bot. Gard. Edinburgh 39:209--486; Cullen 1980 Notes Roy. Bot. Gard. Edinburgh 39:1--207
Rhododendron macrophyllum D. Don ex G. Don
Stem: < 4 m, coarse-branched, twigs stout. Leaf: (6)7--12(17) cm, 3--5(7) cm wide, leathery, evergreen, glabrous, midvein impressed, margin flat. Inflorescence: 1.5--3 cm, 10--20-flowered, bracts deciduous; pedicel +- elongate in fruit. Flower: corolla widely funnel-shaped, white to pink or purple, adaxially brown-yellow-flecked; stamens 10, unequal. Fruit: longer than wide, dehiscing tip to base.
Ecology: Conifer forest margins; Elevation: < 1515 m. Bioregional Distribution: NCo, KR, NCoRO, CCo, SnFrB; Distribution Outside California: to British Columbia. Flowering Time: Apr--Jul
Jepson eFlora Author: Kathleen A. Kron & Walter S. Judd
Index of California Plant Names (ICPN; linked via the Jepson Online Interchange)

Previous taxon: Rhododendron columbianum
Next taxon: Rhododendron occidentale

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Jepson Video for Rhododendron macrophyllum

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Botanical illustration including Rhododendron macrophyllum

botanical illustration including Rhododendron macrophyllum

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Citation for this treatment: Kathleen A. Kron & Walter S. Judd 2012, Rhododendron macrophyllum, in Jepson Flora Project (eds.) Jepson eFlora,, accessed on February 29, 2024.

Citation for the whole project: Jepson Flora Project (eds.) 2024, Jepson eFlora,, accessed on February 29, 2024.

Rhododendron macrophyllum
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©2017 Steve Matson
Rhododendron macrophyllum
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©2017 Steve Matson
Rhododendron macrophyllum
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©2022 California Academy of Sciences
Rhododendron macrophyllum
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©2013 California Academy of Sciences
Rhododendron macrophyllum
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©2022 California Academy of Sciences

More photos of Rhododendron macrophyllum
in CalPhotos

Geographic subdivisions for Rhododendron macrophyllum:
NCo, KR, NCoRO, CCo, SnFrB
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map of distribution 1
(Note: any qualifiers in the taxon distribution description, such as 'northern', 'southern', 'adjacent' etc., are not reflected in the map above, and in some cases indication of a taxon in a subdivision is based on a single collection or author-verified occurence).


Data provided by the participants of the  Consortium of California Herbaria.
View all CCH records
All markers link to CCH specimen records. The original determination is shown in the popup window.
Blue markers indicate specimens that map to one of the expected Jepson geographic subdivisions (see left map). Purple markers indicate specimens collected from a garden, greenhouse, or other non-wild location.
Yellow markers indicate records that may provide evidence for eFlora range revision or may have georeferencing or identification issues.

CCH collections by month

Duplicates counted once; synonyms included.
Species do not include records of infraspecific taxa, if there are more than 1 infraspecific taxon in CA.
Blue line denotes eFlora flowering time (fruiting time in some monocot genera).