Malus sieversii in harsh climates unsuitable for "M. pumila", mainly for increased cold tolerance. "Malus sieversii" has recently been cultivated by the United States Agricultural Research Service, in hopes of finding genetic information of value in the breeding of the modern apple plant. Some, but not all, of the resulting trees show unusual disease resistance. The variation in their response to disease on an individual basis is, itself, a sign of how much more genetically diverse they are than their domesticated descendants. Malus sieversii Malus sieversii is a wild apple native to the mountains of Central Asia in southern Kazakhstan. It has
Malus fusca tough, resilient wood, used for making implements, and for its bark, used for a wide range of medicinal purposes. Malus fusca Malus fusca, with the common names Oregon crabapple and Pacific crabapple, is a North American species of crabapple. It is native to western North America from Alaska, through British Columbia, to northwestern California. It grows in temperate coniferous forest, primarily in the Cascade Range and the Pacific Coast Ranges. "Malus fusca" is a deciduous tree up to tall. Leaves are up to 10 cm (4 inches) long. Flowers are white or pale pink, blooming in Spring. The fruits are