Alnus Mill.


Classical Latin name.

Deciduous trees and shrubs with stalked winter buds. Leaves alternate, finely or deeply toothed. Sexes separate but on the same plant. Flowers arranged into catkins. Male catkins longer than the female with flowers in groups of 3, perianth 4-5 parted, stamens 4. Female catkins with flowers in 2s, the calyx absent. Fruit a small, flat nutlet, mostly with a narrow wing contained in a small, persistent cone-like woody structure with 5-lobed scales.

Generally moisture-loving plants growing naturally near permanent water.

Winter bud with a pronounced stalk; fruiting structures cone-like persisting through winter, scales 5-lobed; male flowers with 4 stamens.

18 taxa are grown at the Mt Lofty Botanic Garden, Adelaide.

About 35 species, mostly northern hemisphere but also in the Americas, extending down the Andes to Peru, growing mostly in wetlands.

Hylander (1957), Murai (1964), Furlow (1979), Nee (1981), Ashburner (1986), Ashburner & Walters (1989).

Source: Spencer, R. (1997). Betulaceae. In: Spencer, R.. Horticultural Flora of South-eastern Australia. Volume 2. Flowering plants. Dicotyledons. Part 1. The identification of garden and cultivated plants. University of New South Wales Press.

kingdom Plantae
phylum   Tracheophyta
class    Magnoliopsida
superorder     Rosanae
order      Fagales
family       Betulaceae
Higher taxa
Subordinate taxa
species         Alnus acuminata Humb., Bonpl. & Kunth
species         Alnus cordata Desf.
species         Alnus glutinosa (L.) Gaertn.
species         Alnus incana (L.) Moench
species         Alnus nitida (Spach) Endl.
species         Alnus rubra Bong.