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Platanus racemosa
WESTERN SYCAMORE

Higher Taxonomy
Family: PlatanaceaeView Description 

Common Name: PLANE-TREE or SYCAMORE FAMILY
Habit: Tree, generally monoecious, wind-pollinated; hairs many-branched. Stem: bark peeling in scaly plates, leaving +- smooth areas of various colors, in age dark, thick, fissured; twig hairs dense. Leaf: simple, alternate, deciduous; lobes, veins generally 3,5(7), palmate; stipules generally leaf-like, free or fused around stem, shed by leaf maturity or not; petiole at base dilated, hollow, +- covering bud; blade hairs dense, +- 0 in age. Inflorescence: heads 1--7, +- evenly spaced on axis, spheric, many-flowered, sessile or on pendent peduncles, generally unisexual; staminate breaking apart in age; pistillate persistent; bracts subtending heads, flowers. Flower: unisexual; calyx cup-shaped, sepals (0)3--6(8), free or united basally. Staminate Flower: petals 3--6, minute or vestigial, fleshy or scale-like; stamens 3--6(8), alternate petals, anthers subsessile, axis above anther expanded, disk-like, +- peltate; carpels vestigial or 0. Pistillate Flower: petals 3--6, minute, or generally 0; staminodes often 3--4; carpels (3)5--9, free, ovary of each superior, 1-chambered, generally 1-ovuled, with 1 +- linear style. Fruit: achenes in spheric head, small, each with hairs from base, shorter hairs up the side; style persistent, beak-like, or deciduous.
Genera In Family: 1 genus, +- 8 species: northern temperate; some cultivated for ornamental, shade; wood generally of limited commercial value, although long ago used for buttons, the trees then called buttonwood.
Unabridged Note: Leaves and twigs with many-branched hairs, each comprising a single multicellular central axis with unicellular lateral, generally whorled rays.
eFlora Treatment Author: Robert Lee Allen
Scientific Editor: Thomas J. Rosatti.
Genus: PlatanusView DescriptionDichotomous Key


Etymology: (Greek: probably broad, for leaves) Note: Fruit length excludes style.

Platanus racemosa Nutt.
NATIVE
Stem: 10--35 m, often leaning; base < 1(2+) m wide; outer bark light gray, tan, inner paler. Leaf: stipules 2--3 cm, generally persistent after maturity; petiole 3--8 cm; blade +- 10--25 cm, +- round, glabrous to +- hairy adaxially, tomentose abaxially. Staminate Flower: sepals 0; petals free. Pistillate Flower: sepals free; style red-tipped, stigma maroon, glabrous. Fruit: head 2--3 cm, +- sessile; achene 7--10 mm, top truncate or tapered, basal hairs +- 2/3 fruit, persistent on fruit head; style generally persistent. Chromosomes: 2n=42.
Ecology: Common. Streamsides, canyons, arroyos; Elevation: < 2000 m. Bioregional Distribution: CaRF, c&s SNF, Teh, GV, CW, SW, DMoj (Mojave River, n of Victorville), nw DSon; Distribution Outside California: Baja California. Flowering Time: Feb--Apr Note: Hybridizes with Platanus ×hispanica Muenchh; some plants in eastern PR with leaves similar to Platanus wrightii S. Watson of Arizona, New Mexico, Mexico, but with fruit of Platanus racemosa.
Unabridged Note: Some plants in eastern PR at northwestern edge of DSon (e.g., Snow, Chino, Andreas canyons of SnJt) appear intermediate to Platanus wrightii S. Watson, Arizona sycamore, of Arizona, New Mexico, Mexico [Platanus racemosa var. wrightii (S. Watson) L. Benson]. These plants generally have leaves hairy but not tomentose abaxially but fruit identical to Platanus racemosa (fruit of Platanus wrightii 5--8 mm, top truncate or abruptly tapered, basal hairs generally 2/3 to = fruit length, style generally deciduous). New growth often killed by sycamore anthracnose fungus, causing angular branching; leaves eaten by sycamore lace bug; bark mined by larvae of sycamore borer moth causing it to roughen, crumble. Leaves may be re-attached by pushing hollow petiole bases back over bud.
eFlora Treatment Author: Robert Lee Allen
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Previous taxon: Platanus ×hispanica
Next taxon: Plumbaginaceae

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Citation for this treatment: Robert Lee Allen 2016. Platanus racemosa, in Jepson Flora Project (eds.) Jepson eFlora, http://ucjeps.berkeley.edu/cgi-bin/get_IJM.pl?tid=38655, accessed on May 24, 2016.

Citation for the whole project: Jepson Flora Project (eds.) 2016. Jepson eFlora, http://ucjeps.berkeley.edu/IJM.html, accessed on May 24, 2016.


Platanus racemosa
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© 2009 Keir Morse
Platanus racemosa
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© 2009 Keir Morse
Platanus racemosa
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© 2014 Neal Kramer
Platanus racemosa
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© 2013 Neal Kramer
Platanus racemosa
click for enlargement
© 2009 Keir Morse
Platanus racemosa
click for enlargement
© 2009 Keir Morse

More photos of Platanus racemosa in CalPhotos


Geographic subdivisions for Platanus racemosa:
CaRF, c&s SNF, Teh, GV, CW, SW, DMoj (Mojave River, n of Victorville), nw DSon;
Markers link to CCH specimen records. Yellow markers indicate records that may provide evidence for eFlora range revision or may have georeferencing or identification issues. Purple markers indicate specimens collected from a garden, greenhouse, or other non-wild location.
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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).

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Data provided by the participants of the Consortium of California Herbaria.
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CCH collections by month

Duplicates counted once; synonyms included.
Species do not include records of infraspecific taxa.
Blue line denotes eFlora flowering time.