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Key to families | Table of families and genera
This text currently parallels The Jepson Manual: Vascular Plants of California, Second Edition that is now available at the University of California Press.
Text appearing in blue on this page will not appear in the printed book; it will be displayed only on the Web. Specimen numbers are hyperlinked to records in the Consortium of California Herbaria data view where possible. Taxa are hyperlinked to entries in the Jepson Interchange via the "[Online Interchange]" link.
Evergreen or not.
Leaf: stipules small, generally early- deciduous.
Staminate inflorescence: catkins, 1–several, pendent, slender, proximal on twig.
Pistillate inflorescence: in upper 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); scales tubercled to not; mature yrs 1 (on younger stems) or 2 (on older stems).
± 600 species: n hemisphere, to n 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.
Unabridged references: [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.]
1. Acorn cup scales thin, not tubercled, shell hairy to woolly inside, at least at tip; bark dark gray or gray-brown to black
2. Lf moderately to deeply lobed, lobes 1–4-toothed, teeth generally bristle-tipped; plant deciduous ..... Q. kelloggii
2' Lf entire to toothed, teeth abruptly pointed to spine-tipped, not bristle-tipped; plant evergreen
3. Lf adaxially convex, margin inrolled or not, obscuring marginal teeth, blade generally widely elliptic to round; fruit mature yr 1 ..... Q. agrifolia
4. Lf abaxially glabrous to sparsely hairy except vein axils hair-tufted ..... var. agrifolia
4' Lf abaxially densely tomentose ..... var. oxyadenia
3' Lf adaxially ± flat, margin not inrolled, blade generally lanceolate to oblong; fruit mature yrs 1–2
5. Lf abaxially ± yellow or ± white woolly; fruit mature yr 1 ..... Q. ilex
5' Lf abaxially glabrous; fruit mature yr 2
6. Lf 2–5 cm, abaxially generally ± shiny, yellow-green; nut gradually tapered from below middle to tip ..... Q. wislizeni
7. Shrub 2–4(6) m ..... var. frutescens
7' Tree generally 10–22 m ..... var. wislizeni
6' Lf 3–9(14) cm, abaxially generally ± dull ..... Q. parvula
8. Tree < 17 m — s NCo, NCoRI, CW (except SCoRI), WTR ..... var. shrevei
8' Shrub 1–6 m
9. Lf margin generally entire; SCoRO (Santa Barbara Co.), n ChI (Santa Cruz Island), e WTR ..... var. parvula
9' Lf margin long-tapered dentate; SnFrB (Mount Tamalpais) ..... var. tamalpaisensis
1' Acorn cup scales generally thick, generally tubercled to ± not, shell glabrous to woolly inside; bark light gray to ± white
10. Acorn nut shell ± woolly inside; fruit mature yr 2; plants evergreen
11. Lf generally 3–8 cm; acorn cup > 1.5 cm wide; generally tree, > 7 m
12. Lf adaxially with lateral veins ± not impressed, abaxially golden-puberulent, glabrous in age ..... Q. chrysolepis
12' Lf adaxially with lateral veins impressed, abaxially densely tomentose, sparsely tomentose in age — ChI ..... Q. tomentella
11' Lf generally 1–3.5 cm; acorn cup < 1.5 cm wide (if > 1.5 cm wide, leaves <= 3 cm); generally shrub, < 7 m
13. Twigs rigid; leaf margin wavy, strongly spine-toothed; blade elliptic to round-ovate; plants 2–6 m, erect ..... Q. palmeri
13' Twigs flexible; leaf margin entire to irregularly serrate, teeth mucronate or spine-tipped; blade oblong or lanceolate to ovate; plants to 5 m, prostrate to erect
14. Lf margin entire or with few irregular spine-tipped teeth; dry chaparral, 100–1800 m, sw PR ..... Q. cedrosensis
14' Lf margin entire to mucro-toothed; montane conifer zone, 900–2800 m, KR, NCoRH, NCoRI, CaRH, SNH, MP ..... Q. vacciniifolia
10' Acorn nut shell glabrous inside; fruit mature yr 1; plants evergreen or not
15. Lf lobed, margins generally without spines; plants deciduous
16. Lf shallowly lobed (sinuses generally < 1/2 distance lobe tip to midrib), adaxially generally dull, green to blue-green
17. Lf adaxially green; acorn cup scales tubercled; ChI ..... Q. ×macdonaldii
17' Lf adaxially blue- or gray-green; acorn cup scales ± tubercled; mainland
18. Shrub, tree < 3 m, evergreen to deciduous; leaves 1.5–5 cm, generally irregularly coarsely toothed, adaxially blue- or gray-green ..... Q. ×alvordiana (2)
18' Tree, deciduous; leaves 3–6(8) cm, ± entire, wavy, or ± lobed, adaxially blue-green ..... Q. douglasii
16' Lf moderately to deeply lobed (sinuses generally > 1/2 distance lobe tip to midrib), adaxially ± shiny, dark green
19. Tree; acorn cup 10–30 mm deep, all scales tubercled; nut 30–50 mm, generally long-conic, tip pointed ..... Q. lobata
19' Shrub, tree; acorn cup 4–9 mm deep, lower scales ± tubercled, upper ± not; nut 20–30 mm, ovoid to ± spheric, tip rounded ..... Q. garryana
20. Tree, 8–20 m, generally with 1 trunk; terminal buds 5–12 mm, fusiform, hairs dense, ± yellow or ± white ..... var. garryana
20' Shrub, small tree, often < 5 m, generally with > 1 trunk; terminal buds 2–5 mm, hairs sparse, brown or ± red
21. Rays of stellate hairs on leaf abaxially generally 4–6, 0.25–0.5 mm; KR, NCoRH, CCo ..... var. breweri
21' Rays of stellate hairs on leaf abaxially generally 6–8, < 0.3 mm; KR, NCoRI, CaRH, SN (except c SNH), SnFrB, SCoRO, ne WTR, MP ..... var. semota
15' Lf generally entire to toothed, not lobed, teeth with spines or not; plants generally evergreen
22. Lvs 7–11(18) cm, serrate, lateral veins of larger leaves generally 20–28, generally straight and prominent; stipules persistent, > 10 mm, silky-hairy ..... Q. sadleriana
22' Lvs 1–6 cm, entire to dentate, lateral veins of larger leaves generally < 20, generally not straight and prominent; stipules early-deciduous, < 10 mm, not silky-hairy
23. Tree generally > 5 m; leaves 2–6 cm, oblong to obovate, entire or ± toothed, adaxially green to blue-green
24. Shrub to small tree, 5–6(10) m; leaf blade (10)20–35(60) mm, adaxially shiny green to dull blue-green, margin entire, dentate, or wavy-dentate ..... Q. ×acutidens (2)
24' Tree, 5–18 m; leaf blade (20)30–60(80) mm, adaxially blue-green, dull, margin wavy-dentate to generally entire ..... Q. engelmannii
23' Shrub generally < 5 m; leaves 1–5 cm, elliptic to ovate or ± round, variously toothed, adaxially generally green
25. Lf 2-colored, adaxially yellow- to gray-green, abaxially ± white, densely fine-tomentose, hairs obscuring lateral veins ..... Q. cornelius-mulleri
25' Lf 1–2-colored, adaxially green to gray- or blue-green, abaxially generally green, not densely tomentose, hairs not obscuring lateral veins
26. Lf generally oblong to obovate, margin wavy to obtuse-toothed; PR ..... Q. ×acutidens (2)
26' Lf elliptic to ovate or ± round, margin toothed, teeth abruptly pointed to spine-tipped
27. Acorn cup thin, scales ± tubercled to not; leaf adaxially gray- or blue-green, dull
28. Acorn stalk 10–15 mm, nut cylindric-ovoid to elliptic, abruptly tapered to tip, 12–23 mm, generally yellow-brown; leaves oblong to elliptic, generally regularly spine-toothed ..... Q. turbinella
28' Acorn stalk 0, nut conic-ovoid, gradually tapered to tip, 20–40 mm, generally dark brown; leaves oblong to elliptic or obovate, irregularly toothed, teeth blunt to weakly spiny
29. Shrub, tree < 3 m; leaves 1.5–5 cm, toothed but not spine-toothed, adaxially blue- to gray-green ..... Q. ×alvordiana (2)
29' Shrub; leaves 1.3–2.8 cm, spine-toothed, adaxially gray-green ..... Q. john-tuckeri
27' Acorn cup thick, scales tubercled; leaf adaxially generally green, ± shiny (dull or not in Quercus durata)
30. Lf adaxially dull, convex, margin often inrolled, obscuring teeth ..... Q. durata
31. Lf adaxially strongly convex, abaxially short-hairy when young; generally on serpentine, NCoR, n SN, n CCo, SnFrB, SCoR ..... var. durata
31' Lf adaxially ± convex, abaxially densely short-hairy when young; not on serpentine, se WTR, SnGb (s slope) ..... var. gabrielensis
30' Lf adaxially ± shiny, flat to ± wavy, not convex, margin generally not inrolled
32. Lf abaxially with spreading, 2–6-rayed hairs — SCo, PR, chaparral or coastal-sage scrub, < 200 m ..... Q. dumosa
32' Lf abaxially with appressed, 4–10-rayed hairs
33. Lf base wedge-shaped or generally truncate or rounded; margin mucro- or spine-toothed; widespread on mainland ..... Q. berberidifolia
33' Lf base gradually tapered, wedge-shaped, or rounded; margin entire, wavy, or ± toothed, teeth generally mucronate; ChI ..... Q. pacifica
Citation for the whole project: Jepson Flora Project (eds.) [year] Jepson eFlora, http://ucjeps.berkeley.edu/IJM.html [accessed on month, day, year]
Citation for an individual treatment: [Author of taxon treatment] [year]. [Taxon name] in Jepson Flora Project (eds.) Jepson eFlora, [URL for treatment]. Accessed on [month, day, year].
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