Ladybugs Photo

The green growing world outside our windows is an incredibly diverse landscape of different plant species. It’s estimated that over 350,000 different kinds of plants exist worldwide.

Many hundreds of trees, shrubs, wildflowers and grasses populate OSA lands. They grow in recognizable groupings, or plant communities, that help distinguish one area from another. The most common plant communities found on OSA lands are chaparral, oak woodland, grassland, riparian and serpentine grassland.

The types of plants that thrive in a given location offer clues to the elevation, soil types, water availability, sun exposure and other resources available there. Being acquainted with plants can help you read the larger patterns of the natural world.

Now showing on OSA lands

California Black Oak
Mayfair Ranch Trail
Rancho Cañada del Oro Open Space Preserve

black oak photo

The most widely distributed of western oak trees, California black oak covers more area in the state than any other oak species. Black oak is considered a critical species for animal habitat, providing food and cover for 14 species of birds, small mammals such as rodents and large mammals including mule deer and black bears. Most common in the northern part of the state, particularly on the western slopes of the Sierra Nevada, black oak was a staple food for many Native Americans. The large acorns were considered to have a superior taste and texture. Black oaks can produce acorns for several hundred years, hitting full production only after seven or eight decades.

Scientific Name: Quercus kelloggii
How to say it: KWER-kus kel-OG-ee-eye


Apple Mint
Along Llagas Creek
Rancho Cañada del Oro Open Space Preserve

apple mint photo

Native to southern Europe and the western Mediterranean, this fragrant herb has become naturalized in the wild. It spreads easily by underground runners and rhizomes and is sometimes considered invasive. The flowers of apple mint, also called woolly mint, are sterile and also very attractive to bees, butterflies and birds. This plant is cultivated as a kitchen herb and for its medicinal value as a treatment for upset stomach. Apple mint is widely distributed in the Pacific states and other parts of North America.

Scientific Name: Mentha suaveolens
How to say it: MEN-tha soo-ay-vee-OH-lens


Tall Nutsedge
Along Llagas Creek
Rancho Cañada del Oro Open Space Preserve

nutsedge photo

Also called flatsedge or umbrella sedge, this California native is found throughout the state, in other Pacific Coast states and in the southeastern United States. Nutsedge needs the moist soils of riparian or wetland environments and thrives in disturbed areas. Its seeds are a food source for water fowl and the plant also has edible tubers on the roots. Native Americans used the tubers as a food source and the leaves in basketry.

Scientific Name: Cyperus eragrostis
How to say it: SY-per-us er-a-GROS-tis


Manyflower Tobacco
Llagas Loop Trail
Rancho Cañada del Oro Open Space Preserve

tobacco photo

This small shrub has extremely sticky foliage and long, white, horn-shaped flowers. Introduced from South America, where it is native in Argentina and Chile, manyflower tobacco is now found in the Pacific Coast states and Nevada. It is widely distributed throughout California.

Scientific Name: nicotiana acuminata var. multiflora
How to say it: ni-ko-tee-AY-na ak-yoo-min-AY-ta var. mul-tee-FLOR-ah



Coastal Woodfern
Mayfair Ranch Trail
Rancho Cañada del Oro Open Space Preserve

woodfern photo

Coastal woodfern favors north slopes and shady creeks and is common on those portions of the Mayfair Ranch Trail. In the fall it is one of the few green plants in the understory. A California native, coastal woodfern is widespread in the state and also grows in Oregon and Washington. The fern is associated with oak woodlands, as its scientific name indicates. Dryopteris comes from two Greek words: drys for oak and pteris for fern. The plant had medicinal uses among Native Americans and the rhizomes also served as a food source.

Scientific Name: Dryopteris arguta
How to say it: dry-OP-ter-is ar-GOO-ta


Southern Honeysuckle
Mayfair Ranch Trail
Rancho Cañada del Oro Open Space Preserve

honeysuckle berries photo

Southern honeysuckle is a sprawling, vine-like shrub with edible red fruit. The flowers of spring are a nectar source for butterflies and the fall berries attract hummingbirds and other birds. The Bay Area marks the northernmost range of this California native which grows in the wild only within the state. In the Santa Cruz Mountains the plant is limited to an area at or near Rancho Cañada del Oro. The genus name Lonicera honors Adam Lonitzer, an early (1500s) German naturalist.

Scientific Name: Lonicera subspicata var.denudata
How to say it: lon-IS-er-a sub-spi-KAY-ta var. den-yoo-DAY-ta


Mayfair Ranch Trail
Rancho Cañada del Oro Open Space Preserve

snowberry photo

This shrub’s berries are just beginning to turn orange. Their bright red appearance in winter explains why toyon is sometimes called Christmas berry or California holly. Birds flock to these berries. Coyotes eat them too. Straight off the bush they taste bitter and astringent to humans, but Native Americans dried or roasted them for cooking. Toyon is green all year and has clusters of tiny white flowers in late spring or early summer.

Scientific Name: Heteromeles arbutifolia
How to say it: het-er-oh-ME-leez ar-boo-tih-FOE-lee-ah


California Buckeye
Mayfair Ranch Trail
Rancho Cañada del Oro Open Space Preserve

buckeye fruit photo

This small tree is native only to California where it is chiefly found in woodland foothill environments. The tree is summer deciduous, so the ripe pear-shaped fruit are particularly visible in the fall. Buckeye fruits are poisonous and most parts of the plant are toxic to people, livestock and wildlife. Despite this, deer are known to browse on buckeye flowers and shoots. Native Americans used buckeye as an emergency food source, to poison fish and to make bowls and drill sticks. The plant had several medicinal uses.

Scientific Name: Aesculus californica
How to say it: ES-kew-lus ka-li-FOR-ni-ka


California Wild Rose
Along Llagas Creek
Rancho Cañada del Oro Open Space Preserve

rosehips photo

The pink blossoms of spring are long gone. Now the thickets of this California native are adorned with bright red fruit, commonly called rosehips. Native Americans ate the berries and also used the fruit to treat a wide variety of ailments. These native rosehips yield a delightful tea. California rose can be found in a number of plant communities including woodlands, chaparral, and grasslands. Because of its thorns and dense growth pattern, wild rose can form impenetrable masses, a source of shelter for small animals.

Scientific Name: Rosa californica
How to say it: RO-za kal-ih-FOR-nih-ka


Bristly Golden Aster
Bald Peaks Trail
Rancho Cañada del Oro Open Space Preserve

Golden aster photo

A California native, this perennial herb is found in central and southern portions of the state. In our region it favors foothill woodland, chaparral and grassland environments. The plant is sometimes called sessile false goldenaster; like other flowers in the Heterotheca family, it has hairy leaves and stems.

Scientific Name: Heterotheca sessiliflora ssp. echioides
How to say it: het-er-o-THEE-ca seh-si-li-FLOR-a ek-ee-OH-i-dees



Common Snowberry
Along Llagas Creek
Rancho Cañada del Oro Open Space Preserve

snowberry photo

Snowberry is common indeed, found throughout the United States and Canada. Because of its wide distribution a large number of Native American communities used this native plant. Some tribes believed the berries were extremely poisonous; others dried and ate them. Different parts of the plant were used to treat skin rashes and burns, sore eyes, teething pains, stomachache, fever and other ailments. Often found in foothill woodlands, snowberry presents small pink blossoms in summer and the namesake berries in the fall.

Scientific Name: Symphoricarpus albus
How to say it: sim-for-ih-KAR-pos AL-bus


California Black Walnut
Llagas Meadow
Rancho Cañada del Oro Open Space Preserve

black walnut photo

Within the green husk of the northern California walnut is a kernel that is an important food source for wildlife. The tree also provides nesting sites for birds and small mammals. California black walnut has a limited distribution in nature and is listed by the California Native Plant Society as a rare and endangered plant. Native Americans relied on the walnut for food and dye for basketry. The tree is widely used as a root stock for commercial walnut production.

Scientific Name: Juglans californica var. hindsii
How to say it: JUG-lans kal-ih-FOR-nih-ka HIND-see-eye


California Coffeeberry
Longwall Canyon Trail
Rancho Cañada del Oro Open Space Preserve

coffeeberry photo

Coffeeberry is an evergreen shrub, native to the state, that is widely distributed in woodland, chaparral and forest environments. The characteristic berries, which turn from red to black as they ripen, are sweet tasting and edible. The plant serves as browse for wildlife and livestock. Native Americans relied on coffeeberry as a food source and for medicinal uses.

Scientific Name: Rhamnus californica
How to say it: RAM-nus ka-li-FOR-ni-ka



Oak Trees
Rancho Cañada del Oro Open Space Preserve

blue oak acorn photo
valley oak acorn photo
coast live oak acorn photo

California has a number of native oak trees including, from left to right, blue oak, valley oak and coast live oak. Each produces distinctive acorns in the fall that play an important part in the life of a woodland community. Blue oaks are widely distributed in the valleys and lower slopes of the Coast Ranges. These deciduous trees are often found in open savannas and grasslands.

Their acorns are palatable to livestock and wildlife, forming an important food source for black-tailed deer, game birds, song birds and rodents. The valley oak is also deciduous and can grow to be 70 feet tall. As with other oaks, Native Americans found many uses for its acorns, which mature in one year. Besides being ground into meal to make bread, biscuits, soup and mush, the acorns had a variety of medicinal uses.

The coast live oak is evergreen, with prickly leaves that often curl under, especially in response to stressors like drought. The tree provides wintering grounds for dozens of bird species and shelter for cavity-nesting birds. The acorns are a diet staple for black-tailed deer, acorn woodpeckers, yellow-billed magpies and scrub jays. Along with ground squirrels, scrub jays give back for what they take: their nut-caching behavior and a small measure of forgetfulness ensure that the 5 percent of acorns they bury and don't dig up help the species regenerate.

Scientific Name: Quercus douglasii (blue)
How to say it: KWER-kus DUG-las-ee-eye

Scientific Name: Quercus lobata (valley)
How to say it: KWER-kus lo-BAY-ta

Scientific Name: Quercus agrifolia (coast live)
How to say it: KWER-kus ag-ri-FO-lee-a


Poison Oak
Rancho Cañada del Oro Open Space Preserve

poison oak photo

Here’s the bad news: poison oak is the most widespread shrub in California. A native plant, it’s found in forest, woodland, chaparral and riparian environments. Urushiol, a toxin in the plant’s oil (found on every part of the plant) is what causes contact dermatitis in humans. Wildlife and livestock, who browse the plant, are not bothered by the toxin. Native Americans had many uses for poison oak, including basketry, skin decoration, cooking and medication.

Scientific Name: Toxicodendron diversilobum
How to say it: tox-i-ko-DEN-dron di-ver-si-LO-bum


Coyote Brush
Mayfair Ranch Trail
Rancho Cañada del Oro Open Space Preserve

coyote brush photo

A California native, coyote brush, or coyote bush, is most often found in chaparral and woodland environments in coastal and northern parts of the state. Its small white or cream-colored flowers are either male or female and occur on separate bushes. The plant is a nectar source for a number of wasp, butterflies and other insect species. Native Americans used the woody stems for arrows and made an infusion from the plant that was used medicinally.

Scientific Name: Baccharis pilularis
How to say it: BAK-ar-is pil-yoo-LARE-is


Naked-Stemmed Buckwheat
Longwall Canyon Trail
Rancho Cañada del Oro Open Space Preserve

naked-stemmed buckwheat photo

This buckwheat can be 3 feet tall, with small single blossom heads on lanky green stems that grow from a single ground-hugging cluster of leaves. True to its name, the plant doesn’t have leaves on its stems. A California native and food plant for several butterfly species, naked-stemmed buckwheat is found throughout the state and also grows in areas along the Pacific Coast. Some Native Americans ate the fresh stems and also used them as straws and pipes.

Scientific Name: Eriogonum nudum
How to say it: er-ee-OG-un-um NOO-dum


Hayfield Tarweed
Mayfair Ranch Trail
Rancho Cañada del Oro Open Space Preserve

tarweed photo

Like all tarweeds, this plant has sticky, heavily scented leaves. Since it blooms in summer, tarweed relies on stored soil moisture and has evolved a deep taproot to survive the seasonal heat and drought. This annual herb is found in grassland, woodland and scrub plant communities. It's a member of the sunflower family. A California native, hayfield tarweed is also found in other western states.

Scientific Name: Hemizonia congesta
How to say it: hem-ih-ZONE-ee-a kon-JES-ta



Harding Grass
Mayfair Ranch Trail
Rancho Cañada del Oro Open Space Preserve

Harding grass photo

Harding grass was introduced to the United States as a forage plant that could withstand dry conditions and heavy grazing. It has spread into natural habitats where it can outcompete native grass species, forming large, dense bushes. Harding grass is now found in much of California, particularly coastal valleys and foothills, and also in a number of other states. It is native to the Mediterranean region.

Scientific Name: Phalaris aquatica
How to say it: fa-LARE-is a-KWA-ti-ka



Iris-Leaved Rush
Longwall Canyon Trail
Rancho Cañada del Oro Open Space Preserve

iris-leaved rush photo

This rush is a California native also found in other southwestern states. It is a perennial that grows in forest, woodland, chaparral and grassland environments, almost always in wetland conditions. Iris-leaved rush spreads by rhizomes (a structure like a bulb). It attracts birds and serves as a food source for the larvae of butterflies. One way to tell iris-leaved rush from other similar plants is to touch the leaves, which have air bubbles you can feel.

Scientific Name: Juncus xiphioides
How to say it: JUN-kus zif-ee-OH-i-dees


California Fuchsia
Mayfair Ranch Trail
Rancho Cañada del Oro Open Space Preserve

fuchsia photo

The showy blossoms of this shrubby plant produce nectar that is an important food source for hummingbirds. Another name for the fuchsia is hummingbird trumpet. A California native, this plant is also found in other western states. It's an evergreen perennial with distinctive silver-green foliage. Fuchsia blooms in late summer and fall.

Scientific Name: Epilobium canum
How to say it: ep-ih-LOH-bee-um KAN-um




Curly Dock
Llagas Meadow
Rancho Cañada del Oro Open Space Preserve

curly dock photo

Curly dock is an introduced plant, native to Europe, that grows everywhere in North America. Like many other plants brought to this continent by settlers, curly dock has a number of medicinal uses and was also used in dyeing. This dock produces extravagant numbers of seeds and spreads easily. It is listed as a weed by the California Invasive Plant Council, but of minor impact. The leaves of curly dock are considered to be edible, but the oxalic acid they contain, which gives them a sour lemony taste, might be toxic in large quantities.

Scientific Name: Rumex crispus
How to say it: ROO-mex KRIS-pus


California Everlasting
Mayfair Ranch Trail
Rancho Cañada del Oro Open Space Preserve

everlasting photo

This fragrant California native has tightly packed blossoms that are attractive fresh or dried. Everlasting is also found in other western states. The plant favors forest, woodland and chaparral environments and is widely distributed throughout the state. Some Native Americans had medicinal uses for the plant, and it is a food source for the larvae of painted lady butterflies.

Scientific Name: Gnaphalium californicum
How to say it: na-FAY-lee-um ka-li-FOR-ni-kum



Slender Wild Oat
Rancho Cañada del Oro Open Space Preserve

wild oat photo

The tall shafts of the dried wild oat color the grasslands tawny gold this time of year. Wild oat is an invasive species, originally from the Mediterranean area of Europe and southwestern Asia. It was first introduced for livestock forage and, with its greedy appetite for spring soil moisture, was quickly able to out-compete native bunch grasses. It is now widespread in California and can be found in most western states. In an example of human adaptation, some Native Americans developed uses for the seeds, often boiling and mashing them into a soup or mush.

Scientific Name: Avena barbata
How to say it: a-VEE-na bar-BAY-ta


Doveweed or Turkey Mullein
Mayfair Ranch Trail
Rancho Cañada del Oro Open Space Preserve

doveweed photo

The seeds of this plant are a favored food source for both mourning doves and turkeys, which accounts for the two common names it's known by. A California native, doveweed grows on dry, sandy soil, often in disturbed areas. It is unpalatable to lifestock and is considered a weed in Australia, a reversal of the invasive plant migration we encounter. Doveweed was used in fishing by Native Americans and early Spanish settlers; another of its names is yerba del pescado. The plant, which has bristly leaves that give off a light spicy fragrance, also had a number of medicinal uses.

Scientific Name: Eremocarpus setigerus
How to say it: er-em-oh-KAR-pos seh-TI-jer-us


Mayfair Ranch Trail
Rancho Cañada del Oro Open Space Preserve

pipestem photo

Pipestem is a climbing plant that can reach heights up to 20 feet or so, using shrubs and low trees for support. In spring the plant has creamy white flowers that open from round buds on long stems. Then the flowers develop into bursts of soft-looking filaments. Fluffy seed plumes dominate in winter as the leaves fall away.

A California native, pipestem is also found in other western states. Native Americans used the roots, bark or stems for cold remedies and pulverized charcoal derived from the plant to treat burns and other skin injuries.

Scientific name: Clematis lasiantha
How to say it: KLEM-at-is las-ee-AN-tha


Plant Communities

All plants live among other plants. Many factors determine how they group themselves. Elements like soil, water availability, slope, and elevation will draw some plants together and exclude others. Interactions among plant species and among vegetation and wildlife also play a part.

Plant communities often have soft edges where species overlap. And they change through time. Disturbances like fire and flooding can cause sudden, large alterations. A gradual evolution from one set of plants to another, called succession, can take decades or centuries to accomplish the same result.

With all the issues to consider, scientists have worked on defining plant associations for years. There are currently several naming systems that emphasize different concepts within the hierarchy of information about plants and plant relationships.

Our purpose here is descriptive, rather than analytical. We use broad terms to describe plant communities as they might appear to the interested visitor on OSA lands. The vegetation groupings most often encountered along the trail are chaparral, oak woodland, grassland, riparian, and serpentine grassland.


chaparral photo

Composed mostly of woody shrubs and small trees, chaparral is primarily a California landscape. Climate – hot dry summers and mild winters with little rain – is the largest influence on this community. Species that can adapt to drought and occasional fire thrive here.

The plants that make up a chaparral community may change from place to place, but the look is much the same: dense, low-growing evergreen bushes (often called brush or scrub) with little space for understory plants.

Reducing evaporation is key to surviving the intense summer heat of inland hillsides and mountain slopes where most chaparral grows. Plants have adapted by developing leaves that are small, thick and leathery. Some have waxy coatings or recessed water-releasing pores. Others align their leaves vertically to limit sun exposure.

They also have evolved fire-survival strategies. Many chaparral natives have deep root systems and will sprout new growth from the crown soon after fire destroys existing wood. Some species have seeds that lie dormant in the soil for years and germinate only after a fire.

Plants often found in chaparral communities include chamise, many species of manzanita and mountain lilac, buckwheat, scrub oak, coffeeberry and toyon.


Oak Woodland
oak woodland photo Several oak species grow on Authority lands, including live oak, blue oak and valley oak. The trees tend to follow an open pattern of distribution, with crowns touching but rarely overlapping. This spacing is implied in the use of the term woodland rather than forest.

The openness of oak woodland communities encourages several layers of associated species. Companion trees may include California bay, buckeye, madrone and California walnut. Common understory plants are blackberry, poison oak, blue elderberry, and some shrubs also found in chaparral, such as toyon and manzanita. On the ground, look for California poppies, lupine, miner’s lettuce and a variety of grasses.

Oak trees share some important characteristics that influence the plant communities clustered around them. A dual root system with a deep tap root and several layers of feeder roots helps draw moisture to the surface and is a boon to other plants.

Leaf litter accumulates from year to year, building a mulch that conserves moisture. It also provides a rich habitat for microorganisms that convert the inert matter to useful nutrients.

The abundant production of acorns attracts more wildlife to oak woodland communities than any other. Hundreds of bird, mammal, reptile and insect species form an intricate web of life, multiplying the food sources and enriching the plant environment.


grassland photo California grasslands are perhaps the plant community most impacted by European settlement. The introduction of large grazing animals and imported feed set the stage for a transformation from perennial native bunch grasses to annual pasture grasses.

The natives, like purple needlegrass, adapt to high summer temperatures and limited rainfall by spreading across the landscape in clumps with open land among them. They also have extremely deep roots to draw on water reserves in the dry season. Through a conservative relationship to available water they are able to maintain a long-term growth strategy. Some individual native bunch-grass plants live for hundreds of years.

Annual grasses, by contrast, tell their whole story in one season. They put multiple shallow roots into the top few inches of spring-moist soil, grow like crazy (which cows appreciate), convert all their energy into copious seeds and then die, leaving behind a multitude of offspring to repeat the whole greedy cycle the following year.

Today most grasslands are dominated by the annuals: wild oats, ripgut brome, foxtail barley, ryegrass and others. The grasses may grow in open meadows or as the ground cover in woodlands. Creating openings for the re-establishment of native grasses and the small broad-leaved plants that grow with them, called forbs, is a high priority for the Open Space Authority.


riparian photo Plants that grow along creeks and rivers (that’s what riparian means) are different in many respects from those that manage without a permanent source of water. Most noticeable are the tallest and largest trees, which lose their leaves in winter. The leaves themselves – large, soft and often broadly exposed to the sun – attest to the milder riparian conditions.

The leaf drop of these sycamores, cottonwoods and alders increases the winter sun available to a second tier of riparian plants. Younger willows, mulefat, blackberry, poison oak and other shrubs and vines often create a dense wall of foliage along creek and river banks. Sedges, rushes and cattails at the water’s edge add another habitat dimension.

Nonetheless, it’s the water itself that defines the environment. Variations in flow from drought to flood can drastically rearrange the structure of the water course. Despite fluctuations, however, the composition of the riparian plant community remains much the same, with key species returning even after massive floods.

It’s estimated that 50% of California’s birds, 40% of mammals and reptiles and 80% of amphibians in a given area will spend at least some part of their lives in a riparian environment. Many species of insects including dragonflies, beetles, butterflies and, of course, mosquitoes also thrive in this space where aquatic and land-based resources meet.


Serpentine Grassland
serpentine photo The defining factor of the serpentine grassland community is the soil. Serpentinite arises from the earth’s mantle along fault zones. Soils derived from the rock are rich in magnesium, low in calcium and include heavy metals such as chromium, nickel, and iron.

Nitrogen, potassium, and phosphorus (primary plant nutrients) may be scarce or absent. The soil, being shallow and rocky, holds water poorly and discourages deep root development. It also tends to erode easily.

This is not a welcoming environment. The influx of nonnative species that came to California along with European settlement couldn’t get much of a foothold. Areas of serpentine soils became a refuge for native plants that had adapted to the difficult conditions over many centuries.

Today serpentine soils cover less than 1.5% of California’s total area but support an estimated 10% of the state’s native plants. A number of special-status plants, including Tiburon paintbrush, Santa Clara Valley dudleya, Mount Hamilton thistle, most beautiful jewelflower and dwarf plantain, host plant of the endangered bay checkerspot butterfly, are found there.

Serpentine grasslands are known for their spectacular arrays of spring wildflowers. Multitudes of cream cups, goldfields, and California poppies, interlaced with popcorn flower, owl’s clover, morning glories and many others, paint the hillsides in brilliant color.