Eucalyptus, gum tree (Eng), eucalipto (Spa), eucaliptus (Cat), eukalitu (Baq), eucalipto (Glg), eucalipto, calipes (Por).
The genus Eucalyptus comprises about 700 species of very aromatic trees and shrubs. All the species that exist in the Iberian Peninsula are introduced. Sometimes they have two types of leaves, all persistent, simple, hairless and with an entire margin. The leaves of young specimens are opposite, wide and often lack stalks, while those of adults are more elongated, alternate and always have an obvious stalk. The French novelist Julies Verne referred to this tree in his book In search of the castaways: “The trees lose their bark every year, instead of their leaves; […] the leaves present their sides to the sun and not their face, and consequently give no shade...” The yellow flowers are very melliferous, and are often borne in groups in the axil of the twigs. The fruit is a capsule (like a small pot with a lid), greenish, brownish or greyish in colour depending on how ripe it is, which contains abundant small seeds.
Flora Iberica states that in the Iberian Peninsula many species are cultivated, some of which have become established in the wild; others are planted in parks and gardens as ornamentals. Only 7 species naturalised species are included here, which have come to make up part of the landscape, and those species that only occasionally escape are not mentioned.
1. Eucalyptus camaldulensis Dehnh. Eucalyptus, River Red gum. Tree up to 50 m tall. Shedding, smooth whitish-grey to brown-red bark. Young leaves are 6-12 cm long and 2-4 cm wide, whitish-blue, lanceolate, and acuminate; adult leaves are 8-25(30) cm long, 0.7-2.5(4) cm wide, narrowly lanceolate, somewhat curved with long tip, and light green in colour. Included in the Atlas of invasive alien plants of Spain.
2. Eucalyptus globulus Labill. Eucalyptus, Tasmanian blue gum, southern blue gum, blue gum. This tree can be up to 70 m in height. One of the tallest trees in the Iberian Peninsula is the Abuelo de Chavín (Chavín's grandfather), near Viveiro (Lugo), which is 67 m tall. Shedding smooth bark. The young leaves are 4-16 cm long 1.5-9 cm wide, oval or oval-lanceolate, with no stalk; adult leaves are 8-35(40) cm long, 1.5-4 cm wide, lanceolate-falcate and somewhat curved with an elongated tip. Flora Iberica differentiates the supspecies globulus and maidenii (F. Muell.) J.B. Kirkp. This species is included in the Atlas of invasive alien plants of Spain.
3. Eucalyptus gomphocephala DC. Eucalyptus, tuart. Tree up to 40 m tall. Persistent, fissured, slightly fibrous, greyish coloured bark. The young leaves are 4-12 cm long, 2-6.5 cm wide, oval-lanceolate, sometimes heart-shaped and with a short stalk; adult leaves are 9-16(18) cm long,1.5-2.5 (4.5) cm wide, lanceolate and slightly curved towards the tip.
4. Eucalyptus gunnii Hook. f. Eucalyptus, cider gum, gunnii. This tree can be up to 30 m tall. Shedding, smooth, white, grey or greyish-green bark. Young leaves are 3-4 cm long, 2-4 cm wide, oval, elliptical or rounded, with no stalk; adult leaves are 4-8 cm long, 1.5-3 cm wide, oval, elliptical, and sometimes a little curved with an elongated tip.
5. Eucalyptus nitens Maiden. Shining gum. A tree measuring up to 60 m tall, but which can reach heights of 90 m in its native area. The bark is grey or brown-grey, fibrous-flaky and persistent in the lower part of the trunk, although in the upper parts it peels off in long strips. Young leaves are ovateor elliptical and blue-green in colour; the adult leaves are lanceolate, 15-25 cm long, 1.5-2.5 cm wide, green and shiny. It does not appear as a naturalised species in Flora iberica, and is not even included in the Atlas of invasive alien plants in Spain. However, according to a 2012 report by the Scientific Committee for Wild Flora and Fauna of the Spanish Ministry of Agriculture, Food and the Environment, it is naturalised and expanding its range in Spain. It is considered to be very dangerous because of its invasive nature, as it is more resistant to cold than other species.
6. Eucalyptus robusta Sm. Eucalyptus, swamp mahogany, swamp messmate. Tree that exceeds 30 m in height. Reddish-brown, rough, spongy and persistent bark that does not strip off. Young leaves are 4-10 cm long, 1-5 cm wide, elliptical-lanceolate or oval, more or less elongated with a narrow tip and with short stalk; adult leaves are 10-15(20) cm long, (2)2.5-7.5 cm wide, elliptical-lanceolate or somewhat curved with an elongated tip.
7. Eucalyptus sideroxylon A. Cunn. ex Woolls. Eucalyptus, mugga, red ironbark, mugga ironbark. This tree can be up to 35 m tall. Persistent, hard, deeply furrowed, dark red bark. The young leaves are 5.5-12 cm long, 0.3-1.5 cm wide, oblong-lanceolate or linear, with very short stalks; adult leaves are (4.5)7-15 cm long, 1-2 (3.5) cm wide, lanceolate or narrowly lanceolate with an elongated tip.