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Key to families | Table of families and genera
Indexes to all accepted names and synonyms:
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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.
7 genera, ± 900 species: generally northern hemisphere. [Li et al. 2004 Int J Plant Sci 165:311–324] 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. Scientific Editors: Thomas J. Rosatti, Bruce G. Baldwin.
Unabridged references: [Li, R.-Q., Chen, Z.-D., Lu, A.-M., Soltis, D. E., Soltis, P. S., & Manos, P. S. 2004. Phylogenetic relationships in Fagales based on DNA sequences from three genomes. Int. J. Plant Sci. 165: 311–324.]
Key to Fagaceae
Evergreen or not. Leaf: stipules small, generally early-deciduous. Staminate inflorescence: catkins, 1–several, pendent, slender, proximal on twig. Pistillate inflorescence: in distal leaf axils, short-stalked; flower generally 1. Staminate flower: stamens 4–10. Pistillate flower: calyx minute, generally 6-lobed; ovary enclosed by involucre. Fruit: nut 1, partly enclosed by cup-like involucre (cup) with appressed scales (nut and cup = acorn), remnants of perianth and style persistent as small point at tip; scales tubercled to not; mature in years 1 (on younger stems) or 2 (on older stems).Key to Quercus
± 600 species: northern hemisphere, to northern South America, India. (Latin: ancient name for oak) [Manos et al. 1999 Molec Phylogen Evol 12:333–349] Many named hybrids; those (3) treated here form widespread populations; most others occur as single individuals, and some but not all of these are mentioned here, under the first parent treated (alphabetically). Reproduction of many species declining due to habitat degradation or loss as well as disease. Quercus robur added, as waif.
Unabridged references: [Cottam, W. P., J. M. Tucker, & F. S. Santamour. 1982. Oak hybridization at the University of Utah. State Arboretum of Utah Publication No. 1. Salt Lake City; Hardin, J. W. 1975. Hybridization and introgression in Quercus alba. Journal of the Arnold Arboretum 56: 336–363; Manos, P. S., Doyle, J. J., & Nixon, K. C. 1999. Phylogeny, biogeography, and processes of molecular differentiation of Quercus subgenus Quercus (Fagaceae). Molec Phylogen Evol 12: 333–349.]
Shrub to small tree < 3 m, evergreen to deciduous. Leaf: 1.5–5 cm; petiole 2–5 mm; blade generally oblong to widely elliptic, adaxially dull, blue- to gray-green, abaxially fine-hairy, dull, pale green, tip obtuse to abruptly pointed, margin generally irregularly coarsely toothed. Fruit: cup 10–16 mm wide, 8–10 mm deep, cup- to bowl-shaped, scales ± tubercled, light brown; nut 20–40 mm, generally narrowly ovoid, distally acute, asymmetric or not, shell glabrous inside; mature in year 1.
Dry slopes, hills; 180–1300 m. Tehachapi Mountain Area, South Coast Ranges, Western Transverse Ranges. Hybrids involving Quercus douglasii, Quercus john-tuckeri, considered sp. by Eastwood. Jan–Mar [Online Interchange]
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Citation for the whole project: Jepson Flora Project (eds.) 2013. Jepson eFlora, http://ucjeps.berkeley.edu/IJM.html, accessed on May 24 2015
Citation for this treatment: [Author of taxon treatment] 2013. Quercus, in Jepson Flora Project (eds.) Jepson eFlora, http://ucjeps.berkeley.edu/cgi-bin/get_IJM.pl?tid=40533, accessed on May 24 2015
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|Geographic subdivisions indicated for the distribution of Quercus X alvordiana|| Markers link to CCH specimen records. If the markers are obscured, reload the page [or change window size and reload]. Yellow markers indicate records that may provide evidence for eFlora range revision or may have georeferencing or identification issues.
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(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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