Flora of New Zealand Series

oak

Large, widespreading, deciduous tree (to c. 30 m tall in cultivation), with very rough, dark grey, fissured bark. Shoots glabrous, brown or brownish green, lenticellate. Buds usually ciliate, without surrounding stipules. Petiole usually < 2 mm but sometimes to 10 mm long, glabrous. Stipules subulate, soon caducous. Lamina on adult shoots (2)-4.5-18 × (1.5)-3-9 cm, narrowly to broadly obovate, glabrous at maturity or slightly hairy on midrib below, dull above, membranous, ± lyrate-pinnatifid with 3-7 pairs of obtuse teeth or lobes; lower teeth often shallowly crenate; largest lobes at widest part and usually extending ?-1/2 distance to midrib; base cordate or auriculate and almost or entirely concealing petiole. ♂ catkins 3-9 cm long; rachis hairy or nearly glabrous; lower fls distant; perianth 1-1.7 mm long, pilose, often reddish; stamens 3-9. Fruiting peduncles 3-13 cm long, with 1-3 fertile frs; frs reaching maturity in first year. Cup usually 1.5-2 cm diam.; scales ovate, puberulent, appressed or nearly so. Acorn 2-4 cm long, oblong-ellipsoid or oblong-ovoid, 1/4-⅓ enclosed by cup.

N.; S.

Europe, W. Asia 1880

Sporadic escape from cultivation around parks, plantations, and old estates, in scrub and waste places.

FL Sep-Oct.

Oak or English oak is widely planted, particularly in colder areas. Mature trees usually fruit prolifically and spontaneous plants frequently occur in their vicinity. The sp. has been previously known in N.Z. as Q. pedunculata.

Q. robur is very variable in lf size and degree of lobing, as well as length of peduncle and size and shape of acorns. Probably most of the original introductions were from the British Isles where great variation exists. In Britain there has been introgression with the other indigenous sp., Q. petraea (Mattuschka) Liebl., durmast or sessile oak. Some variation in Q. robur in N.Z. also suggests hybridism and both spp. are in cultivation here. Typical Q. petraea has a longer petiole with the lamina base cuneate to subcordate and therefore not obscuring the petiole; also the fruiting peduncle is very short and often obscured by the small cluster of acorn cups. The name Q. × rosacea Bechst. is available for hybrids between these 2 spp.