Oaks of the World

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  Quercus dumosa
Author Nuttall 1842 N. Amer. Sylv. 1: 18
Synonyms dumosa var. elegantula (Greene) Jeps. 1923
x macdonaldii var. elegantula Greene 1889
Local names California scrub oak ; coastal scrub oak ; scrub oak ; Nuttal's scrub oak ; el chaparral ; " chaps " ;
Range California ; Mexico (North of Baja California); from Pacific coasts to 300 m ;
Growth habit not exceeding 3 m; crown rounded, as if pruned; branches stiff;
Leaves 1-2.5 x 0.6-1.5 cm; semi-evergreen, stiff, thick; elliptic or oblong; pointed, base rounded to sometimes cuneate; margins wavy, entire or with sometimes 3-9 shallow lobes or teeth (if present, the teeth are sometimes spiny); shiny green, nearly hairless above ; pale and densely pubescent beneath, with stellate trichomes showing large rays visible without lens; petiole 1-4 mm;
Flowers March to April;
Fruits acorn 1.2-2.5 cm; narrowly ovoid, elongated, pointed, enclosed 1/3 or 1/4 by cup; cup subsessile (3 mm long stalk), scaly; matures in 1 year; kernel very bitter but edible;

Bark, twigs and
buds

bark dark brown, scaly; twig reddish grey; bud red brown, globose, glabrous, 1-2 mm;
Hardiness zone, habitat a little tender (but withstands -14°C); prefers dry soils;
Miscellaneous -- Sub-genus Quercus, Section Quercus, Subsection Dumosae;
-- A. Camus n° 176;
-- Threatened (IUCN Red List Category : EN).

-- Hybrids with Q.lobata and Q.engelmannii are put together under the name Q.x kinseliae ;

-- The term "Q.dumosa" has been applied to almost all the scrubby oaks of California; but 5 species have been separated as true species : Q.turbinella, Q.john-tuckeri, Q.cornelius-mulleri, Q.berberidifolia and Q.pacifica; the "true" Q.dumosa is a quite rare species, restricted to low elevations; it differs from other scubby oaks essentially in having large, visible hairs on the leaves undersides.

Subspecies and
varieties

-- For Trelease: numerous formas...

-- -- Q.durata Jepson 1909 Fl. Calif. 1: 356
= Quercus dumosa subsp durata (Jeps.) A.Camus 1935
= Q.dumosa var. bullata Engelm. 1877
= Q.dumosa var. revoluta Sarg. 1895
leather oak ;
to 3 m; densely branched; bark scaly; young shoot yellow grey, tomentose; bud brown, globose, 1-2 mm; leaves 1.5-4 x 0.7-2 cm, evergreen, leathery, oblong to elliptic, stongly convex; margins revolute, wavy and spiny, base cuneate, apex slightly pointed; dark dull green (greyish) above with appressed, persistent hairs; pale pubescent grey beneath with 1-2 mm long tawny hairs; acorn cylindrical 1.5-2.5 cm, enclosed 1/2 or more in warty cup; hardiness zone : 7; California, 150-1500 m;
-- Q.durata has a variety :
Q.durata var. gabrielensis Nixon et C.H.Muller 1994
= San Gabriel Mountains Leather Oak
1-3 m, with densely hairy twigs; leaves leathery weakly convex, with longer hairs beneath (2-4 mm), shiny green above; petiole hairy less than 5 mm long; acorn 2 cm, stalkless, enclosed by warty, glabrous cup; 450-1000 m; California (Los Angeles County); it would be better to consider it as an ecotype of Q.durata.

-- In Sta Catalina Island, a species is now separated from Q.dumosa, and from Q.berberidifolia, and is today considered as a true species : Q.pacifica Nixon et C.H.Muller

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