blue elderberry
Sambucus mexicana
Family: Caprifoliaceae.
Type: Deciduous shrub.
Branching: Opposite. (Note this refers to the arrangement of leaves, not leaflets.)
Leaves: Pinnately compound leaves (one axillary bud per compound leaf, remember). The leaflets are variable in number.
Twig: Twigs are very sloppy, drooping, and knotted; this sloppiness in its growth pattern is distinctive. Smaller twigs are reddish and have small warts (mnemonic: Sam has warts).
Flower & Fruit: Fruit is a black or blue berry that hangs down in clusters. They can have a white coating called glaucous bloom, however; this is the same type of white bloom found on blueberries and huckleberries.
Miscellaneous: This plant is in the same family as honeysuckle. The elderberry prefers moist sites near creek beds, associated with oak woodlands in drainage areas.
Oppositely arranged plants can be remembered with the mnemonic Mad Cap Buck. "Mad" is maple, ash, dogwood. "Cap" is Caprifoliaceae: honeysuckle, elderberry, snowberry, and so forth. "Buck" is for the California buckeye.