Ulmus ×hollandica Mill.
elm
Tree up to 40 m high, suckering prolifically and with epicormic shoots. Bark grey, strongly fissured. Twigs hairy at first, becoming smooth and grey or brown in second year. Adult lvs broadly ovate to ovate-lanceolate, acute or acuminate, serrate, scabrid and often glandular above and below, also often villous near midvein below, 5-12 cm long; lateral veins in 9-14-(18) pairs; basal auricle usually not overlapping petiole. Lvs of basal shoots mostly somewhat shorter. Petioles much < blade. Stipules when remaining, oblong, entire, c. 7-12 mm long. Fr. broadly obovate, light brown, 2-3 cm long.
N.; S.: locally established throughout.
Europe 1940
Waste places, riverbeds; often spreading from established cultivated trees within urban areas.
FL Aug-Sep FT Sep-Oct.
U. × hollandica is widely cultivated in temperate areas, but its origin is not known with certainty. It may be a triple hybrid, U. carpinifolia Gled. × U. glabra Hudson × U. plottii Druce. This hybrid is distinguished by: suckers and epicormic shoots numerous, with corky flanges up to 2 cm wide; lvs ovate, acute; serrations coarse, broad-based, rather blunt; veins in 9-14 pairs; seed close to the terminal notch of the samara. The Huntingdon elm, a hybrid between U. glabra and U. carpinifolia also grows wild in N.Z. This
cv. is sometimes named U. × vegeta 'Vegeta', or sometimes treated as a form of U. × hollandica, viz. U. × hollandica 'Vegeta'. It is distinguished by the suckers being less numerous and not corky; lvs ovate to ovate-lanceolate, acuminate; serrations rather sharp; veins in up to 18 pairs; seed not reaching the terminal notch of the samara. However, it is often difficult to place specimens within either of these forms satisfactorily.
U. glabra, wych elm, is also commonly cultivated in N.Z. and is often grafted on to rootstocks of U. × hollandica; U. × hollandica may become established by suckering from such grafted trees. U. glabra is distinguished from U. × hollandica by the short petiole which is obscured by the prominent overlapping auricle of the lamina. Reports of naturalised plants of U. campestris and U. carpinifolia are probably based on specimens of U. × hollandica.
