A Web Guide to the Eucalypts
Subgenus Eucalyptus L'Herit.
Type: Eucalyptus obliqua L'Herit., Sert. Angl., 18 (1788), t. 20.
Trees or mallees; bark smooth and excorticating in flakes or ribbons, or persistent and long-fibrous or short-fibrous or flaky. Juvenile leaves opposite for few or many nodes, glabrous, or with raised papillose glands, or with acute thick-walled unicellular trichomes radiating from prominent glands. Adult leaves glabrous, disjunct or rarely opposite, sometimes dorsiventral. Venation variable, closely-or widely-spaced, oblique, acute or sub-parallet. Renantherin often present. Inflorescences of lateral umbellasters of 1 to many flowers. Calyx calyptriform. Corolla absent, suppressed from earliest stages of development. Anthers elliptical, versatile, dorsified, dehiscing by separate parallel slits, or reniform, adnate, dehiscing by broad confluent slits. Stigma rounded or tapered, smooth, with short or long papillae, entire or hollow (with emerging stylar canal). Ovules anatropous, arranged in 2 vertical rows in each loculus (each primary row secondarily 2-rowed in E. coccifera). Cotyledons orbicular, emarginate, not folded in embryo. Seeds usually cuboid or pyramidal, dorsally rounded; hilum ventral. Fruit woody; capsule usually not deeply sunken; valves enclosed or exserted.
Diagnosis: Plant glabrous, or papillose or with radiating trichomes on juvenile growth. Umbellasters lateral, axillary. Calyx calyptriform. Petals suppressed. Ovules in 2 vertical rows in each loculus (secondarily 4-rowed in one species).