Go to: Keys to Identifying Selected Plant Groups in the SGM
Sumac Family Primer for the San Gabriel Mountains
Common and widespread, plants in the sumac family typify our image of southern California hillsides, particularly in the San Gabriel Mountains on the coastal side of the Front Range. Sometimes, in winter, they are the only green plants you see. The sumac family includes large, rounded shrubs, with simple, aromatic, evergreen leaves and smaller, thicket-like shrubs with deciduous and three-parted leaves. A non-native species, the familiar pepper tree, has naturalized around old homesteads.
The sap of the plants in the sumac family is resinous, sometimes milky. All contain skin irritating compounds to a greater or lesser degree. The infamous and irritating poison oak belongs to this family.
The flowers are very small and come in parts of five. They are borne in clusters at the ends of branches or sometimes between branches. The fruit also comes in clusters like small bunches of grapes and is berry-like with a single, hard seed in the middle surrounded by flesh that may be tart. The leaves are alternate.
The number of records is an rough indicator of frequency. You are almost sure to see those with the largest number of observation records.
1. Are the shrubs, large and rounded, and the leaves, simple (not divided into smaller leaflets) and evergreen (not dropping off in winter)?
3. Are the plants treelike with evergreen, drooping, compound leaves having about 15 leaflets?
- Yes. Is the leaf flat and the tip rounded with no point?
- Yes. It is Lemonade berry Rhus integrifolia
- No. The leaf has a taco-like fold and a pointed tip. Go to 2.
2. Is the leaf shiny dark-green and does the leaf taper gently to a point?
- No. The plants are trees, vines, or thicket-like shrubs with compound leaves. Go to 3.
4. Are there three leaflets and a stalk on the middle terminal leaflet?
- Yes. It is the Peruvian Pepper Tree Schinus molle.
- No. The plants are vines or thicket-like shrubs with deciduous leaves having 3 to 5 leaflets. Go to 4.
- Yes. It is Poison Oak Toxicodendron diversilobum
- No. There are 3 to 5 leaflets and no stalk on the middle terminal leaflet. It is Squawbush Rhus trilobota.
Malosma laurina, Rhus laurina
- Common name: laurel sumac
- Leaf: shape=folded along midrib like a taco, more when dry; longer, narrower and thinner than sugar bush and lemonade berry; tip=rounded with abrupt point; color=green with yellow veins and a long, red stalk; aroma=apples or bitter almonds (to me, it's the characteristic "trail" smell)
- Flower: color=white; dried flower stalk remains on plant, visible at ends of branches
- Fruit: color=white; texture=without hairs
- Profile: large, rounded shrub
- Elevation range: between 0' and 3000'
- Locations: Dalton Canyon, Little Tujunga Canyon, Mt. Wilson Trail, Rubio Canyon, Sturdevant Trail, Van Tassel Canyon, unspecified Angeles National Forest
- Comments: frost sensitive, outside leaves turn crimsom red
- Number of records: 23
- Common name: lemonade berry, lemonade sumac
- Leaf: shape=flat, leathery, oblong; tip=rounded, no point, but edges can be toothed; color=dark glossy green; aroma=spicy
- Flower: color=pinkish white
- Fruit: color=red; texture=covered with sticky bumps and short hairs
- Profile: large, rounded shrub
- Elevation range: between 0' and 2953'
- Locations: Arroyo Seco, Little Dalton Canyon Wash, Monrovia Canyon, Pacoima Wash, San Gabriel Canyon, unspecified Angeles National Forest
- Number of records: 9
- Common name: sugar bush, sugarbush, sugar sumac
- Leaf: shape=oval, folded along the midrib; tip=tapers gently to a sharp point; color=glossy green; aroma=?
- Flower: color=red sepals, white petals, looking like tight clusters of little pink balls
- Fruit: color=red; texture=sticky, bumpy
- Profile: large, rounded shrub
- Elevation range: between 0' and 4265'
- Locations: Glendora Mtn. Road, Millard Canyon, Red Mountain, San Gabriel Canyon, Warm Spring, unspecified Angeles National Forest
- Number of records: 69
- Common name: squawbush, squaw bush, skunkbush, skunkbush sumac
- Leaf: shape=3 leaflets, sometimes the top one looks like 3 making it appear to have 5; tip=middle leaflet does not have a stalk; color=green; aroma=skunk-like
- Flower: color=yellow
- Fruit: color=red; texture=sticky, hairy
- Profile: low, thicket-like shrub
- Elevation range: 0 and 5500 feet
- Locations: Big Tujunga Creek, Devil's Punchbowl, Granite Mountain, Mill Creek Summit, Monrovia Canyon, Red Rock Mountain, Soledad Canyon, Tanbark Flats, unspecified Angeles National Forest
- Comments: ozone sensitive, leaves get splotchy
- Number of records: 14
- Common name: Peruvian pepper tree
- Leaf: shape=compound, about 15 linear leaflets; tip=pointed; color=light green; aroma=spicy
- Flower: color=yellowish
- Fruit: color=red; texture=without hairs
- Profile: weeping, willowy branches
- Elevation range: unknown
- Locations: San Dimas Canyon, characteristic tree of California missions
- Comments: not native to California, naturalized in the wild around old homesteads
- Number of records: 1
Toxicodendron diversilobum, Rhus diversilobum
- Common name: Poison oak
- Leaf: shape=3 leaflets, sometimes 5; tip=the middle terminal leaflet has a stalk; color=bright green, turning various shades of red in fall, deciduous in winter; aroma=?
- Flower: color=greenish white
- Fruit: color=white, turning beige; texture=shiny like a pearl
- Profile: twiggy upright stems or a clinging vine
- Elevation range: between 0 and 5000 feet
- Locations: moist, shaded areas along most trails; unspecified Angeles National Forest
- Comments: the most widespread California shrub; please read the links below about the hazards of poison oak
- Number of records: 76
Sources and Other Web Information
CalFlora Occurrence Database Observation records for the San Gabriel Mountains.
Current Bug, Snake and Varmint Reports in the San Gabriel Mountains: Other Pests
Family Secret Cashew (sumac) family members have an unpleasant chemical in common. From the Orange County Register
Let's Talk about "Poison Oak" From Palo Alto Troop 5...Pacific Skyline Council...Boy Scouts of America
Online Key to Local Species has more information on the differences between poison oak and squawbush
A California Flora by Philip A. Munz. University of California Press, 1968.
Flowering Plants, the Santa Monica Mountains, Coastal and Chaparral Regions of Southern California by Nancy Dale. Capra Press, 1986.
The Jepson Manual Higher Plants of California edited by James C. Hickman. University of California Press, 1993.
Native Shrubs of Southern California by Peter H. Raven. University of California Press, 1966.
A Natural History of California by Allan A. Schoenherr. University of California Press, 1995.
Roadside Plants of Southern California by Thomas J. Belzer. Mountain Press Publishing Company, 1984.
Sierra Nevada Natural History by Tracy I. Storer and Robert L. Usinger. University of California Press, 1963.
Copyright © 2000 by Jane Strong and Tom Chester.
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Updated May 6, 2000.