I’ve heard that in Australia and New Zealand, the term “bitzer” is used for something made of a little bit of this and a little bit of that. I think of that term when I think of Acer negundo, a maple species known as boxelder and ashleaf maple, and sometimes referred to as poison ivy tree. These common names come from the tree’s features: whitish colored wood, which is similar to that of boxwood, the leaf’s shape, which resembles some species of elder, and the positioning of its compound leaves, which resembles that of ash. Leaf clusters have a resemblance to poison ivy. Maple features are sap that can be tapped for syrup, and seeds which are winged and known as samaras. Acer negundo is a true bitzer.
It has been said that boxelder is probably the 
most common maple species in North America, and the maple species with the greatest range. However, I have found them only in very scattered areas of the Atlanta area. These pictures are from trees I found in a low-lying area of Pope Road near Douglasville, GA. Boxelder is native to low, wet areas of North America, but it is adaptable to dry sites and occasional drought. It prefers bright sunlight, but tolerates partial shade. It tolerates extremely cold weather and floods. Though short-lived and easily broken, boxelder is hardy, fast-growing, and a prolific seeder. It spreads easily in urban areas, and has been planted in prairies and drier areas of the Western United States where few other trees can grow.
There are six varieties of boxelder in North 
America, with several specific to geographic locations. Those found in Georgia may reach 60 to 70 feet in height, and are mostly found in the Piedmont region. California boxelder may reach 40 feet in height and Rocky Mountain boxelder may reach 80 feet in height. Boxelder trunks are often multiple, and extreme sucker growth can create thickets. The tree’s bole or trunk is short and rarely over 3 feet in diameter. Bark of young trees is light brown and smooth, while that of more mature trees is darker brown with narrow, rounded ridges separated by very shallow fissures. The wood, which is light, close-grained, and soft, is worthless for lumber but suitable for turning. When wet, it has a foul smell. Short-lived, all varieties usually live less than 100 years.
The boxelder has rounded to irregular form. Widely spreading branches are smooth, green, and have no bark. Many grow low and are crooked, seeking spots of sun. Leaflet petioles are green, and covered by a whitish to pink or purple waxy coating when young. Leaves are compound with 3 to 5 (and sometimes 7) irregularly and coarsely toothed leaflets. Leaflets appear pinnately, or in pairs, and where petioles attach to the stem there are no leaf buds. This absence of leaf buds is a characteristic of compound leaves, and no other maple in North America has compound leaves. Each leaflet is elliptic to ovate, pointed at the tip, and rounded at the base. Leaflets may be 3 to 4 or more inches long, and are light green and smooth above and slightly paler below. Leaflets emerge in mid-April to late May. Autumn leaf color in Georgia is dull yellow, but western varieties may have more interesting colors.
Unlike other maples, boxelder has male and female flowers borne on separate trees. Both sexes appear as leaflets emerge in mid-April to late May, and are yellow-green. They are wind-pollinated, and the pollen is an allergen. Female flowers produce clusters of V-shaped winged nutlets or samaras that some call “helicopters”. These clusters have been compared to dirty socks. They mature in August-September, and are shed through autumn and winter. These pictures were made in mid-August.
Uses of the boxelder are varied. Western areas value the tree as a native that can grow where most trees can’t. The tree can be a good shade 
tree, but is usually avoided due to limb breakage, pollen, easy germination of seeds, and boxelder bugs. Trees grown by houses invite problems with boxelder bugs coming into the house in autumn, and severe allergic reactions to pollen. Boxelder seeds from trees grown around horses contain a toxin that can trigger seasonal pasture myopathy, which can be fatal. Boxelder wood is useful for paper pulp, charcoal, crates, and turned objects. Sap can be tapped for making maple syrup or sugar, but this is rarely done because a gallon of syrup requires 60 gallons of sap and the syrup has a strong taste.
Boxelder is a maple with unusual features, a true bitzer. Discovering a maple with compound 
leaves can leave one with a “Ah hah, I found you out” feeling, and glad you learned how to see this.