Jepson (2012) (APG System)

Order

Sapindales

Family

Sapindaceae

Jepson (1993) (Cronquist System)

Order

Sapindales

Family

Aceraceae

Plant Relationships

California Species:

Acer circinatum
Acer macrophyllum
Acer negundo var. californicum

(Vine maple)
(Bigleaf maple)
(Box elder)

Other Species:

Acer palmatum
Acer platanoides
Acer saccharinum
Acer saccharum

(Japanese maple)
(Norway maple)
(Silver maple)
(Sugar maple)

Description

Growth Forms:

All members of Acer in California are trees. Acer circinatum could be described as a large shrub.

Branching:

Opposite branching

Leaves:

Acer circinatum and Acer macrophyllum are palmate. Acer negundo is pinnately compound.
In the eastern US, maple leaves are known for their red, orange and gold colors in the fall. Bigleaf maple leaves usually turn a modest yellow, although they can be bright yellow in certain locations. Box elder leaves turn a pale yellow before drying up and falling off.

Flowers:

Maple flowers are often showy, in panicles or racemes. In spite of their appearance, they are wind pollinated.

Fruit:

The seeds are in pairs, and each seed has a wing. The wings appear during flowering, but the seed is not viable until fall. When the seeds dry and fall off, they flutter to earth and are carried a short distance by the wind.

Growing Conditions

Natural Habitat:

Maples are known for growing in riparian zones but they also grow in openings in a forest canopy or on open hillsides if the soil conditons are favorable. Maples are a late successional genus.

Shade Tolerance:

Maples are shade tolerant. They often seed in the shade of other trees and emerge through openings in the canopy. They grow better, however, in the full sun.

Soil and Moisture:

Maples prefer mesic soil that is well structured, mature and somewhat fertile.

Horticulture and Restoration

Horticultural Comments:

Maples can be used as specimen trees and have good structure with strong limbs if grown in the full sun. Bigleaf maples are particularly useful as landscape subjects. Vine maple is often used as a large shrub or small tree.
Maples grown in dense shade have many thin branches that are prone to breakage. Acer macrophyllum and A. negundo grown in the shade make poor landscape subjects.

Wildlife Habitat:

The main value is for nesting habitat for birds, although the seeds are useful to wildlife as well.

Restoration Projects:

Bigleaf maple (Acer macrophyllum) and Box elder (Acer negundo var. californicum) are generally used for riparian restoration projects.