Malus Mill.
Family: Rosaceae
Malus image

Key to Wisconsin Malus

    • 1a.Leaves unlobed, closely singly or doubly serrate, convolute in bud; anthers yellow. 2

    • 1b.Leaves with shallow acute lobes and coarse or irregular teeth, conduplicate in bud; anthers pink. 3

    • 2a.Lower leaf surfaces and floral tubes glabrous or sparsely pubescent when young; calyx deciduous. M. baccata

    • 2b.Lower leaf surfaces and floral tubes densely pubescent when young; calyx persistent. M. pumila

    • 3a.Lower surfaces of mature leaves tomentose. M. ioensis

    • 3b.Lower surfaces of mature leaves glabrous throughout or puberulous on the veins. 4

    • 4a.Flowers with 3 styles; calyx lobes deciduous. M. toringo

    • 4b.Flowers with 5 styles; calyx lobes persistent in fruit. M. coronaria

Apples are an economically important but taxonomically difficult group of plants. Introduced crabapples are increasingly escaping in the state but are underrepresented in herbaria; this is no doubt due to the difficulty involved in identifying them. They are commonly found in thickets, fields, pine plantations, along forest edges, and on open hillsides. There are hundreds of hybrids and cultivars of the ornamental Asian species so determining which taxa are escaping may be impossible. The key below will probably not work with every wild apple one encounters in the state, but it does include all those species that we know are established or native.