[Update: We had originally identified this as Boston Ivy, but a kind correspondent pointed out the error.]
An Asian vine now considered an invasive species in our area, especially in the city. The National Park Service gives us this description:
Plant: deciduous, woody, perennial vine that resembles grape and climbs by non-adhesive tendrils at the base of each leaf; grows to 15-20 ft.; young twigs are usually pubescent; stem pith is white (grape is tan or brown) and is continuous across the nodes (except for V. rotundifolia, grape is interrupted by a diaphragm across the node); bark is dotted with lenticels and does not peel (grape bark lacks lenticels and peels or shreds).
Leaves: alternate, simple, 3-5 lobed to highly dissected with heart-shaped base and coarsely toothed margins, shiny underneath with hairs on veins.
Flowers, fruits and seeds: tiny, greenish-white flowers with petals separate at their tips occur in flat-topped clusters opposite the leaves; appear in summer (June through August); fruit is a speckled berry in colors ranging from aqua to pink to purple; each berry carries 2-4 seeds.
Spreads: by seed that is eaten by birds and other small animals and dispersed in their droppings.
Look-alikes: native species of grape (Vitis) and peppervine (Ampelopsis) including heartleaf peppervine (Ampelopsis cordata) which is native to the Southeast and has unlobed leaves and smooth (hairless) stems; other native Ampelopsis have compound leaves.
These vines sprawled over a chain-link fence in the back streets of Oakland, where they were blooming and fruiting in the middle of October.