Aceraceae (Maple Family)

Box Elder
Acer negundo
NATIVE 

The box elder’s leaves are coarsely serrated along margins in a somewhat lobed variable shape.  They are green above and paler green below and are arranged opposite to each other.  The yellowish green flowers appear after the leaves come out in spring. Flowers are small, yellow, born in long racemes. The double winged fruits, resembling helicopter blades, are called samaras. 

Caprifoliaceae (Honeysuckle Family)

Blue Elderberry
Sambucus mexicana
NATIVE 

Blue elderberry prefers canyon bottoms where water is available in summer, but also grows on dry hillsides. Elderberries often start as multi-trunked shrubs that mature into small trees.  The deciduous leaves are compound.  The blue berries are eaten by wildlife and were dried for later use by the Ohlones.  Early Californians made jam and wine from the berries.  The creamy flat-topped flower clusters can be dipped in pancake batter and fried.  Elderberry stems have a soft white central pith that can be removed, leaving a hollow tube that serves as a flute, clapper, or gambling stick.

Fabaceae (Pea Family)

Mimosa
Albizia lophantha
NON NATVE 

A semi-evergreen 6 meter tree with leaves that are deep green.  The leaves are twice pinnately divided.   Native to Asia.

Western Redbud
Cercis occidentalis
NATIVE  

Flower is very showy, light to dark pink in color, 1.3 cm long, appearing in clusters in March to May before the leaves. Bark is dark in color, smooth, later scaly with faint ridges. Fruits are flattened, dry, brown, pea-like pods, 5 to 10 cm long.  The flat, elliptical, brown seeds are 0.64 cm long. Maturing in July to August.

Fagaceae  (Oak or Beech Family)

Coast Live Oak 
Quercus agrifolia
NATIVE 

Coast live oak is a tall tree with smooth gray bark.  The 2.5 to 7.6 cm long oval, evergreen leaves are stiff and leathery and often do not lie flat. They are shiny dark green on the top surface and dull pale-green below, with rusty fuzz in the angles formed by the midrib and the side veins and scattered sharp spines along the edges. The acorn matures in the first year.  The slender, pointed nut is 2.5 to 3.8 cm long.

Mission area has many old oaks that are over 100 years old.  Early pictures of the area show many oaks lined the Mission Creek.

Hippocastanaceae (Chestnut Family)

California Buckeye
Aesculus california
NATIVE

Compound leaf with 5 leaflets.  Flowers bloom in a long, terminal cluster, which produces a leathery capsule with 1-3 large brown shiny seeds each with a pale scar (a buck’s eye).  Seeds are poisonous to humans.

Juglandaceae (Walnut Family)

Northern California Black Walnut
Juglans californica
NATIVE

Northern California black walnut is a small tree, often branching from near the ground.  The bark is dark brown with deep ridges.  The pith is dark brown.  The deciduous compound leaves are 23 to 38 cm long with 11 to 19 slender leaflets. There are soft hairs on the main veins on the underside of the leaf.  The smooth nut has shallow grooves, is flattened at the ends, and is much smaller and thicker than the English walnut.  It is often found around old Indian encampments in Central California.  It is used as a stock upon which commercially grown English walnut is grafted because its roots are better adapted to local soil conditions and may hybridize with this species.

English (Persian) Walnut  
Juglans regia
NON NATIVE  

English walnut is native to southeastern Europe, the Himalayas, and China.  It is a large tree with smooth gray bark.  The deciduous leaves are 20 to 41 cm long and have 7 to 9 broad leaflets.  The end leaflet is larger than the others.  The thin-shelled nut is divided into two halves.  English walnut is often grafted onto California black walnut rootstock so that it will grow better in local soils.

Lauraceae (Laurel Family)

California Bay Laurel
Umbellularia californica
NATIVE 

This evergreen bay tree has simple leathery lance-shaped leaves.  When crushed, the pungent leaves smell like bay rum.   Bay leaves are used to season stews and sauces, and are placed on pantry shelves to discourage insect pests.  Clusters of small fragrant yellow flowers appear in December.  The fruit resembles a small avocado and turns purplish when mature.  The heavy, fine-grained laurel wood and burls are used to make plates, bowls, novelties and furniture and are often sold as pepperwood or myrtle.

Moraceae (Mulberry Family)

Edible fig
Ficus carica
NON NATIVE

Forms a shrub or low spreading deciduous tree. Lives in mild winters with hot dry summers.  Originally from Asia.  It has large (5-15 cm), simple leaves with 5 but sometimes 3 or 4 lobes.  Bark is smooth, silvery gray.

Myrtaceae  (Myrtle Family)

Blue Gum Eucalyptus
Eucalyptus globulus
NON NATIVE 

Blue gum is a very tall tree that has been planted throughout California.  It was introduced from Australia and Tasmania in the late 1800s as a fast-growing lumber crop; however, the wood twists as it dries, making it unsuitable for working.  Its roots are very efficient at finding water at the expense of more desirable native species. Eucalyptus oil is used in cough and cold medications.  The peeling outer bark ignites readily and firebrands can be carried a great distance by updrafts produced by fires.

Oleaceae (Olive Family)

Oregon ash
Fraxinus latifolia
NATIVE

Found in riparian habitats.  Tree is dioecious with small greenish flowers that appear with leaves.  Fruits are elliptical samaras that ripen in late summer.  Leaf is compound with 5-9 ovate leaflets.  Bark is thin, smooth and gray green when young.  Drought resistant but can tolerate flooding.

Pinaceae (Pine Family)

Monterey pine
Pinus radiata
NATIVE (central coastal California) 

Trees are rapid growers and can grow to 15-30 meters.  Bark is gray to red-brown with deep “V” furrows.  Needles are long in bunches and deep yellow-green.

Platanaceae  (Sycamore Family)

Western Sycamore
Platanus racemosa
NATIVE

 Western sycamore grows along creek beds.  It is a large deciduous tree with heavy twisted branches.  Its “jigsaw puzzle” bark is smooth and ashy-white with greenish-gray and tan patches.  The broad leaves are light green above and paler and rusty-hairy below.  The fruits are contained in bristly “button-balls” borne in clusters on the flower stalk. 

Salicaceae (Willow and Poplar Family)

Fremont Cottonwood
Populus fremontii
NATIVE

Cottonwoods are common trees found in local creeks within Alameda County.  The deciduous leaves are spade-shaped and become golden in fall.  Wind blowing through the trees sounds like running water.  Male and female flowers are borne on separate trees.  The female tree has cottony seeds that are dispersed by the wind that bloom between March and April. This tree is well known for its ability to grow quickly with heights up to 35 meters.  

Red Willow 
Salix laevigata
NATIVE

Red willow is a medium-sized deciduous tree that always grows near water.  The bark of mature trees is dark and rough; young twigs may be red to yellow-brown.  The narrow leaves are green and shiny above, whitish below, and usually widest below the middle.  Male and female flowers are borne on separate plants and appear soon after the leaves in early spring. The tiny seed produced by the female catkin has a cottony “fluff” and may be carried a great distance by the wind.  Because all willows root easily and grow quickly, they have potential for holding soil on steep slopes.  The flexible willow shoots were used by the Ohlone Indians to make baskets and huts. Willow bark contains salicin, which our bodies convert to salicylic acid, the active pain-relieving ingredient in aspirin.

Arroyo Willow  
Salix lasiolepis
NATIVE

Arroyo willow is a small tree or branching shrub.  It grows along perennial or summer-dry creeks, or in arroyos.  The bark of the mature tree is deep gray.  Twigs are yellowish to brownish.  The narrow leaves are dark green and smooth above and hairy to smooth beneath, with margins that are sometimes toothed and slightly rolled under.  The leaves are usually wider above the middle.  Pliable willow twigs were used by the Ohlones for making baskets and constructing temporary huts.  Willow bark is a source of salicylic acid, the active ingredient in aspirin, and was used to relieve pain.

Taxodiaceae  (Bald Cypress Family)

Coast Redwood
Sequoia sempevirens
NATIVE (Coastal California)

This majestic tree ranges from 60-110 meters tall.  Trunks are usually enlarged with swelling or burls at the base.  Cones are small, about 12-35 mm long and reddish brown.