OregonFlora: Quercus vacciniifolia vs. Quercus acerifolia

	Quercus vacciniifolia	Quercus acerifolia
	huckleberry oak
Habit	Shrubs evergreen, to 1.5 m, solitary; bark usually smooth, pale to medium gray; twigs glabrous or puberulent.
Buds	ovoid, red-brown; tips rounded, glabrous or puberulent; terminal buds 2–2.5 mm.
Leaves	oblong to oblong-ovate or elliptic, 1.9–3.6 × 0.7–1.9 cm, bases rounded to truncate; margins entire or rarely spinetoothed, unlobed; secondary veins 6–8 on each side; tips acute or obtuse, sometimes rounded or apiculate; surfaces abaxially glaucous, glabrous, rarely with scattered, appressed, yellow hairs, adaxially glabrous or with appressed, yellow hairs; petioles 2–5 mm.
Fruits	ripening 2nd year; nuts ovoid to ellipsoidal, 11–22 × 9–14 mm; tips acute to rounded; cups shallowly bowl-shaped; thin, 5–10 × 10–19 mm, covering only base of nuts; scales plane, appressed, attachment scars 2–4 mm wide.

	Quercus vacciniifolia	Quercus acerifolia
Distribution	[WildflowerSearch map] [BONAP county map]	[BONAP county map]
Discussion	Rocky places in chaparral or open woodlands. Flowering May–Jul. 300–1600 m. Casc, CR, Sisk. CA, NV. Native. Huckleberry oak is closely related to Q. chrysolepis, and shrubby forms of the latter species can sometimes cause confusion. The habit of the shrub is different; Q. vacciniifolia tends to form low shrubs around rock outcrops in the mountains, usually with a dense crown having many crowded, parallel, slender, pliable stems. Quercus chrysolepis has a more open crown, and the branches are stiffer, more divergent, and not so much branched. These characters show some variation, and the two species may be difficult to distinguish from isolated twigs in the herbarium. Hybrids are sometimes found where they grow together, usually around 1000 m elevation. The name was originally spelled “Quercus vaccinifolia,” but a recent change in the International Code of Botanical Nomenclature (Art. 60.8, Vienna code) requires the addition of a second “i.”
Source	Flora of Oregon, volume 2, page 751 Alan Whittemore
Sibling taxa	Q. chrysolepis, Q. garryana, Q. kelloggii, Q. palustris, Q. robur, Q. rubra, Q. sadleriana	Q. chrysolepis, Q. garryana, Q. kelloggii, Q. palustris, Q. robur, Q. rubra, Q. sadleriana, Q. vacciniifolia
Web links	Local floras: CA, OR Local Web sites: CalFlora, CalPhotos, Flora NW, PNW Herbaria WildflowerSearch iNaturalist (observations) USDA Plants Database LBJ Wildflower Center SEINet Plants of the World Online Encyclopedia of Life Wikipedia Google Image Search	Local Web sites: Flora NW, PNW Herbaria WildflowerSearch iNaturalist (observations) USDA Plants Database LBJ Wildflower Center SEINet Plants of the World Online Encyclopedia of Life Wikipedia Google Image Search

Quercus acerifolia

huckleberry oak

Habit

Shrubs evergreen, to 1.5 m, solitary; bark usually smooth, pale to medium gray; twigs glabrous or puberulent.

Buds

ovoid, red-brown;

tips rounded, glabrous or puberulent; terminal buds 2–2.5 mm.

Leaves

oblong to oblong-ovate or elliptic, 1.9–3.6 × 0.7–1.9 cm, bases rounded to truncate;

margins entire or rarely spinetoothed, unlobed;

secondary veins 6–8 on each side;

tips acute or obtuse, sometimes rounded or apiculate;

surfaces abaxially glaucous, glabrous, rarely with scattered, appressed, yellow hairs, adaxially glabrous or with appressed, yellow hairs;

petioles 2–5 mm.

Fruits

ripening 2nd year; nuts ovoid to ellipsoidal, 11–22 × 9–14 mm;

tips acute to rounded; cups shallowly bowl-shaped; thin, 5–10 × 10–19 mm, covering only base of nuts;

scales plane, appressed, attachment scars 2–4 mm wide.

Quercus acerifolia

Distribution

[WildflowerSearch map]

[BONAP county map]

Discussion

Rocky places in chaparral or open woodlands. Flowering May–Jul. 300–1600 m. Casc, CR, Sisk. CA, NV. Native.

Huckleberry oak is closely related to Q. chrysolepis, and shrubby forms of the latter species can sometimes cause confusion. The habit of the shrub is different; Q. vacciniifolia tends to form low shrubs around rock outcrops in the mountains, usually with a dense crown having many crowded, parallel, slender, pliable stems. Quercus chrysolepis has a more open crown, and the branches are stiffer, more divergent, and not so much branched. These characters show some variation, and the two species may be difficult to distinguish from isolated twigs in the herbarium. Hybrids are sometimes found where they grow together, usually around 1000 m elevation. The name was originally spelled “Quercus vaccinifolia,” but a recent change in the International Code of Botanical Nomenclature (Art. 60.8, Vienna code) requires the addition of a second “i.”

Source

Flora of Oregon, volume 2, page 751
Alan Whittemore

Sibling taxa