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Quercus pacifica

Higher Taxonomy
Family: FagaceaeView DescriptionDichotomous Key

Common Name: OAK FAMILY
Habit: Shrub, tree, evergreen or not; monoecious. Leaf: simple, alternate, petioled; margin entire to lobed; stipules small, generally deciduous. Staminate Inflorescence: catkin or stiff spike, many-flowered. Pistillate Inflorescence: 1--few-flowered, generally above staminate inflorescence; involucre bracts many, generally overlapping, flat or cylindric. Staminate Flower: calyx generally 4--6-lobed, minute; petals 0; stamens 4--12+. Pistillate Flower: calyx generally 6-lobed, minute; petals 0; ovary inferior, style branches generally 3. Fruit: 1 nut subtended, partly enclosed by scaly, cup-like involucre or 1--3 nuts subtended, enclosed by spiny, bur-like involucre; mature years 1--2. Seed: generally 1.
Genera In Family: 7 genera, +- 900 species: generally northern hemisphere. Note: Wood of Quercus critical for pre-20th century ship-building, charcoal for metallurgy; some now supply wood (Fagus, Quercus), cork (Quercus suber), food (Castanea, chestnut). Lithocarpus densiflorus moved to Notholithocarpus.
eFlora Treatment Author: John M. Tucker, except as noted
Scientific Editor: Thomas J. Rosatti, Bruce G. Baldwin.
Genus: QuercusView DescriptionDichotomous Key

Habit: Tree 5--15 m, deciduous; trunk bark scaly, +- gray; twigs tomentose. Leaf: 4--7 cm; petiole 3--10 mm; blade oblong to obovate, adaxially glabrous to sparsely hairy, green, +- shiny, abaxially densely appressed-stellate-hairy, +- pale green, tip obtuse to rounded, margin lobes 2--6(8) per leaf, shallow, generally pointed. Fruit: cup 10--20 mm wide, 6--10 mm deep, hemispheric, scales tubercled, canescent; nut 20--35 mm, conic-oblong to ovoid, distally acute to +- obtuse, shell glabrous inside; mature in year 1.
Note: Considered a species by Greene but derived from hybrids involving Quercus pacifica, Quercus lobata, perhaps others; needs study.

Quercus pacifica Nixon & C.H. Mull.
Habit: Shrub to 2 m (small tree to 5 m), generally evergreen; twigs finely hairy, +- red or +- brown, glabrous in age, gray. Leaf: 1.5--4 cm; petiole 2--5 mm; blade obovate or oblong, adaxially green, abaxially light green with minute appressed stellate hairs, in age glabrous, base gradually tapered, wedge-shaped, or rounded, tip generally rounded, margin entire, wavy, or +- toothed, teeth generally mucronate. Fruit: cup 8--20 mm wide, 5--15 mm deep, hemispheric to top-shaped, scales moderately to strongly tubercled; nut 20--30 mm, ovoid to cylindric, distally acute to +- obtuse, shell glabrous inside; mature in year 1.
Ecology: Slopes, ridges, canyons, chaparral, coastal scrub, oak woodland, pine forest; Elevation: < 610 m. Bioregional Distribution: ChI (Santa Cruz, Santa Rosa, Santa Catalina islands). Flowering Time: Mar--Apr Note: Hybridizes with Quercus lobata.
eFlora Treatment Author: John M. Tucker
Jepson Online Interchange
Listed on CNPS Rare Plant Inventory

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botanical illustration including Quercus pacifica


Citation for this treatment: John M. Tucker Quercus pacifica, in Jepson Flora Project (eds.) Jepson eFlora,, accessed on November 20, 2017.

Citation for the whole project: Jepson Flora Project (eds.) 2017, Jepson eFlora,, accessed on November 20, 2017.

Quercus pacifica
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© 2001 Tony Morosco
Quercus pacifica
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© 2015 Keir Morse
Quercus pacifica
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© 2015 Keir Morse
Quercus pacifica
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© 2014 Steve Matson
Quercus pacifica
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© 2015 Keir Morse
Quercus pacifica
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© 2015 Keir Morse

More photos of Quercus pacifica in CalPhotos

Geographic subdivisions for Quercus pacifica:
ChI (Santa Cruz, Santa Rosa, Santa Catalina islands).
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.
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).

View elevation by latitude chart
Data provided by the participants of the Consortium of California Herbaria.
View all CCH records

CCH collections by month

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