Identifying Alternate Pinnate Leaves

A partially pinnate leaf (i.e. with not all leaflets free) is indicative of Bastard Service.

Odd-shaped leaflets suggest either Golden Rain Tree, with extensively-lobed leaflets, or Tree of Heaven with blunt teeth at the leaf base.

Serrated leaves could belong to a number of species: Black Walnut usually has leaves with the terminal leaflet missing; Caucasian Wingnut and the other wingnut species are often large trees and have large leaves and characteristic nuts in hanging strings; Stag's-horn Sumach is immediately identifiable by its hairy shoot; Common Rowan and the other rowans have smaller leaves and are richly berried by autumn.

Unserrated leaves could also belong to a number of species: if they are not those of Common Walnut, with a distinctive large terminal leaflet, they are most likely to belong to a member of the Leguminosae:

•	Common Laburnum and Voss's Laburnum have leaves with just three leaflets
•	False Acacia is common, with neatly-rounded leaflets tipped by a tiny bristle and with paired spines; the yellow ‘Frisia’ is also very common
•	Honey Locust is quite frequent and has rather narrower leaflets with wavy margins, and, in thorned forms, clustered thorns; once again there is a frequent yellow form
•	Pagoda Tree is rather less common and has elegant, neatly-pointed leaflets and no thorns
•	Mimosa has tiny leaflets
•	Kowhai has small, cotoneaster-like leaflets
•	Pink Siris is a rare species with small leaflets and delicate pink flowers

 
 

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Copyright © 2007 Philip Brassett