Flora of New Zealand Series

white poplar

Tree to c. 25 m high, usually spreading, suckering profusely. Bark grey, rather smooth to shallowly fissured. Shoots white-tomentose, terete. Buds white, with appressed tomentum, not viscid. Young lvs not aromatic. Petiole 1.5-5 cm long, white-tomentose, slightly compressed. Lamina on vegetative shoots 3-10 × 2-9.5 cm, ± deltoid, with 3-5 lobulate or toothed primary lobes; lamina on adult shoots smaller, ovate, ovate-oblong or suborbicular, lobed or strongly toothed, always white, loosely tomentose below and at first above, later glabrous or nearly so on upper surface, green and shining; margin lacking translucent band; base truncate, rounded or subcordate, glandless; apex obtuse or rounded. Catkins ♀, ± pendent, 2-8 cm long at anthesis. Rachis villous. Bracts 3-3.5 mm long, membranous, shining, brown in upper part, incised to shallowly toothed, prominently long-ciliate. Cup-shaped disc 0.5-0.8 mm deep, glabrous or somewhat villous; margin slightly sinuate. Ovary glabrous; stigmas slender, whitish. Capsule containing dense, white, cottony hairs, especially towards base.

N.; S.: especially E. areas.

S.C. Europe, W. Asia, N. Africa 1904

Modified vegetation - along roadsides, around farms, waste places, coastal dunes.

FL Sep.

White poplar has been planted in many localities but is generally regarded as undesirable because of its strongly suckering habit which has resulted in large stands in coastal eastern South Id areas. All specimens from fully naturalised plants are ♀ and represent a single clone. In October the dehiscing capsules shed so much white hair that they give the appearance of a snowstorm. Some wild material can be referred to cv. 'Nivea' (sometimes treated as var. nivea Aiton), silver poplar, which is a persistent juvenile form notorious for its prolific suckering habit resulting in dense thickets of shoots. It has chalky white petioles and lf surfaces and a lamina which is always deeply 3-5-lobed.

The cultivated ♂ clone cv. 'Pyramidalis' is either a tall completely columnar tree, or has only the secondary branches erect; the lvs on adult shoots become glabrous or nearly so below. This cv. also suckers freely and can become a nuisance, although as yet it has not been confirmed as establishing beyond the immediate vicinity of planted trees. As yet there have not been reports of seedlings where these 2 cvs of P. alba grow in close proximity.