Sibley Volcanic Regional Preserve

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         (426 plants)
Thanks to the East Bay Regional Park District for this list.

    
Alfalfa
Medicago sativa
  • Height 1 - 3 ft.
  • CA Bloom Jun - Aug
  • Like a clover but taller, and with serrated leaves.
  • Purple pea-like flowers cluster in small groups at the end of multiple stems.
  • Used in agriculture, you'll find Alfalfa in disturbed areas near farms.
  • Not CA native



Clusters of small purple pea-like flowers.

Leaves in 3, serrated, with short petioles connecting them to the stem.

Grows erect. The pea pod twists into a coil.
Alkali Bulrush
Bolboschoenus maritimus
  • CA Bloom Aug - Sep
  • Flat, narrow stems to about four feet tall.
  • Found near the edge of salt water.
  • Widespread in California and around the world.
  • CA native



Flowers dark brown with tan bristles.

Flowers group in the joint of flat stems.

Stands erect with noticeable brown flowers
Alum Root
Heuchera micrantha
  • CA Bloom May - June
  • Alum Root sends wispy stems two feet in the air, supporting dozens of tiny white or pink flowers.
  • Leaves at the base of plant are shaped like mittens.
  • Found in wet areas, often near moss.
  • CA native



Tiny flowers on leafless wispy stems about 2 feet tall.

Leaves connect to the base of the plant on long stalks. They're fuzzy and roundish.

Leaves form a thick basal cluster, with tiny flowers appearing to be suspended in air above them.
American Dogwood
Cornus sericea
  • CA Bloom Jun - Aug
  • White 4-petaled flowers in round bunches
  • White berries
  • Medium tall shrub grows to 12 feet
  • Opposite leaves, green above and hairy grey below
  • Found in damp areas
  • CA native



Opposite leaves, strong veins, pointed tips.

Showy clumps of flowers turn into white berries.

4-petaled white flowers grow in clumps at the end of stems.
American Vetch
Vicia americana
  • CA Bloom May - Jun
  • Flowers with pink, violet and white parts.
  • Tendrils, modified leaves, allow the plant to climb on other plants.
  • Alternate compound leaves.
  • A widespread understory plant.
  • CA native



Purple pea-like flowers

Alternate compound leaves.

Vine grows to a foot long. One inch pea pods for fruit.
American Vetch (1)
Vicia americana ssp. americana
  • Height 1 - 2 ft.
  • CA Bloom May - Jun
  • Flowers with pink, violet and white parts.
  • Tendrils, modified leaves, allow the plant to climb on others.
  • The vine stem can grow to 4 feet long, but the plant is generally under 2 feet tall.
  • Alternate compound leaves.
  • Widespread understory plant.
  • CA native



Small but bright flowers

Lots of small compound leaflets.

Long thin leaves and purple flowers make this a vetch.
Annual Beard Grass
Polypogon monspeliensis

Annual Beard Grass is topped by large, fluffy spikes. They're framed by flat, rough, green leaves to 8" long.

Soft, dense spikelets are green until they mature. There are lots of spikelets in the spike, each producing 3 awns.

Long awns let light through around the edge but the center is opaque.
Annual Blue Grass
Poa annua


Bright green or yellow-green leaves are soft, generally flat and come to a blunt point at the tips.

Like all Bluegrasses, the inflorescence is open and spikelets have no awns. Florets are membranous.

Annual Blue Grass grows quickly in disturbed areas. Plants are small but have many leaves.
Annual June Grass, Bristly Koeleria
Koeleria gerardii
  • CA Bloom Apr - Jul
  • Not CA native




  • Arroyo Lupine
    Lupinus succulentus
    • Grows to 3 ft. on erect, sparsely hairy stems.
    • CA Bloom Feb - May
    • This annual flower produces 6" clusters of purple pea flowers.
    • Wide-tipped leaflets grow on long (2-6") stalks.
    • It is abundant in open or disturbed areas, and is often seeded on road banks.
    • CA native



    Look for radial leaflets that are wider near the tip. Their fleshy top feels rubbery.

    Here's a closeup of the flower. The yellow pistil is just sticking out of the right-hand keel. The left part is the banner.

    Stacks of whorled flowers have white banner spots that turn magenta with age.
    Arroyo Willow
    Salix lasiolepis
    • Height 7 - 35 ft.
    • CA Bloom Feb - May
    • This is the most common willow in California.
    • It's deciduous and is found near water.
    • Look for narrow leaves that are wider near the tip than at the base.
    • CA native.



    Leaves are about 5 inches long, smooth-sided and narrow. They're pale/hairy underneath, and wider near the tip than near the base.

    Classic pussies with yellow stamens. The buds are fused together (not overlapping) before they open.

    This willow has many trunks, sometimes growing as a tree, and sometimes as a tangled shrub.
    Australian Fireweed
    Senecio glomeratus
    • CA Bloom Apr - Sep
    • Yellow composite flowers group at the top of a branched 6 foot plant.
    • Leaves are alternate and deeply lobed.
    • Found in disturbed sites below 1,000 feet, generally near the coast.
    • Not CA native
    • Moderately Invasive


    Composite flowers group at the top of the stem. They have no "petals" ( ray flowers).

    Leaves clasp the stem, grow to about 6 inches, and are deeply lobed.

    Grows to 6 feet or so, with lots of flowers near the top of the stem.
    Baneberry
    Actaea rubra
    • Height 8 in. - 3 ft.
    • CA Bloom May - Jul
    • Baneberry is a shrub that grows to about 3 feet tall.
    • Leaves are coarsely toothed.
    • Bright red or white berries are hard to miss, and warn animals that they're poisonous.
    • White showy flower clusters.
    • Found in shady, moist woodland.
    • CA native



    Leaves have deeply toothed margins. Poisonous berries are red or white, with a black dot.

    White showy clusters of flowers stand out on their own stalks. Each flower has many long stamens.

    Leaves are compound and sharply toothed. Leaves and flowers are on separate stalks.
    Beaked Hazelnut
    Corylus cornuta
  • CA Bloom Feb - Mar
  • Tiny petals
  • Alternate leaves
  • Streambanks slopes
  • CA native




  • Bearded Clover
    Trifolium barbigerum
    • Height to 1 ft.
    • CA Bloom Feb - May
    • Brown, pink, violet, white flower
    • Irreg petals
    • Alternate leaves
    • CA native




    Bearded Sprangletop
    Leptochloa fusca ssp. fascicularis
  • CA Bloom Jun - Oct
  • CA native




  • Beardless Wild Rye
    Elymus triticoides


    This rye has 2-ranked spikelets that connect directly to the stem. There is space between each alternating spikelet.

    Hollow stems (like straws) connect at solid joints. Leaves are about 1/4" wide and a foot long.

    Prominent blue-green leaves are 4-12" long and grow away from the stem. Found in moist habitats with heavy soils.
    Bee Plant
    Scrophularia californica
    • Height 2 - 4 ft.
    • CA Bloom Feb - May
    • Bee plant is tall, with prominent triangular leaves and tiny brownish-red flowers.
    • Small flowers are less than 1/2" across and have a nectar disk to reward pollinating bees.
    • Opposite leaves have stalks that connect to the stem.
    • Found in moist places below 8,000 feet.
    • CA native



    This view of the flower from below shows two rounded petals on top, two side petals, and one folded out like a tongue.

    A square stem supports large, opposite, toothed leaves. This might make you think "Mint" but it's not.

    Bee Plant grows several feet high with opposite, narrow leaves sticking straight out. Flowers are on horizontal stalks near the top.
    Bermuda Grass
    Cynodon dactylon

    Spikelets are tiny (<1/10") and purple. Tight colonies of plants are connected by rhizomes and stolons.

    Two rows of spikelets connect to one side of finger-like branches that all join at the top of the stem.

    The ligule is white and hairy. Leaf blades are short, flat and fleshy.
    Big Leaf Mistletoe
    Phoradendron leucarpum ssp. macrophyllum
  • Shrub
  • Green flower
  • Tiny petals
  • Opposite leaves
  • CA native




  • Big Scale Balsam Root
    Balsamorhiza macrolepis
  • CA Bloom Mar - Jun
  • Yellow flower
  • Many petals
  • Basal leaves
  • Slopes
  • CA native
  • Endangered (CNPS 1B)




  • Big Tarweed
    Blepharizonia plumosa
  • CA Bloom Jul - Oct
  • CA native
  • Endangered (CNPS 1B)




  • Bioletti Cudweed
    Pseudognaphalium biolettii
    • CA Bloom Jan - May
    • Flowers are white on the outside and yellow on the inside.
    • Alternate leaves are wide at the base and clasp the stem.
    • Leaves and stem are covered with short fine hair, not sticky but sharply scented.
    • Found in coastal chaparral and in mixed evergreens in the foothills.
    • CA native



    Shiny papery phyllaries surround tiny yellow aster flowers.

    Many tiny brown fruits.

    Grows to 3 feet, sometimes woody at the base.
    Bird's Foot Lotus
    Acmispon brachycarpus
    • Height 6 in. - 1 ft.
    • CA Bloom Mar - Jun
    • Yellow flower
    • Pea petals
    • Alternate leaves
    • CA native




    Bird's Foot Trefoil
    Lotus corniculatus
    • Height to 8 in.
    • CA Bloom May - Jul
    • Tiny fruit clusters look like a bird's foot.
    • Short, thin compound leaves make bundles along the stem.
    • Find it in open grasslands, wetlands, and compacted soil along roads and trails.
    • Other Trefoils
    • Not CA native



    Tiny pea flowers cluster at the end of the stem.

    Each plant is small. See fruit pods on the left, compound leaves in the middle, and a flower cluster on the right.

    Colonies of Bird's Foot Trefoil can be prominent in grasslands. It is sometimes vine-like, with prostrate stems up to 20 inches.
    Bitter Cherry
    Prunus emarginata
    • CA Bloom Apr - May
    • White 5-petaled flowers about 1/2" across smell nice.
    • Leaves yellow-green with tightly-spaced veins.
    • A shrub to medium-sized tree.
    • Canyons, slopes, ridges, open woods in nutrient-rich soil.
    • CA native



    3-10 small flowers per cluster, 5 separate petals, long stamens.

    Leaves to 3 inches long with bumpy edges. Red cherries, each with its own stalk.

    Bitter Cherry forms thickets on sunny hillsides.
    Black Cottonwood
    Populus trichocarpa
    • CA Bloom Feb - Apr
    • A large riparian tree with alternate leaves
    • Leaf stems are round (Fremont Cottonwood's is flattened).
    • Widely distributed in California, except the central valley.
    • CA native



    Leaf tops are glossy dark-green. Undersides are pale. Leaves are long and pointed, with small teeth on the edge.

    Alternating secondary veins connect to a central one.

    Grows near running water. Trunks get very large, and the tree height often exceeds 100 feet.
    Black Mustard
    Brassica nigra
  • CA Bloom Apr - Jul
  • Yellow flower
  • Four petals
  • Alternate leaves
  • Not CA native
  • Moderately Invasive




  • Blue Blossom
    Ceanothus thyrsiflorus var. thyrsiflorus
    • Height to 30 ft.
    • CA Bloom Mar - May
    • Blueblossom is an evergreen shrub with a prodigious display of sweet-smelling flowers.
    • Look for grooves running the length of the stem.
    • Grows well on poor soil. Found in a variety of habitats.
    • CA native



    Blueblossom is full of tiny, fragrant flowers when it blooms in spring.

    Alternate leaves have 3 veins that join at the base. The underside is dull and the top is shiny.

    Leaves are shiny and dark green on top, growing to 2 inches long. They have glandular bumps on the side.
    Blue Dicks
    Dipterostemon capitatus
    • CA Bloom Feb - Apr
    • Look for a tight bunch of 6-petaled flowers on a single stem, about 1 foot tall.
    • Flowers can be purple, pink or white.
    • This common springtime flower is widespread where there is sun.
    • Compare to Ookow
    • CA native



    A tight bunch of 6-petaled flowers appears at the top of a tall, wavy stalk.

    The centers of the flowers feature a forked, white sheath that surrounds yellow-tipped stamens.

    Long, narrow leaves grow from the base of the plant. Below, the roots connect to food-storing corms.
    Blue Elderberry
    Sambucus mexicana
    • CA Bloom Mar - Jul
    • A large shrub with clusters of white flowers, plus compound leaves indicate an Elderberry.
    • Berries are black but appear blue because of a waxy covering.
    • Grey bark with vertical furrows.
    • Common on stream banks and open places in forests.
    • CA native



    White flat-topped clusters of flowers are easy to spot.

    Berries with a waxy covering makes them look powdery.

    Compound leaves with 5 - 9 toothed leaflets.
    Blue Fescue
    Festuca idahoensis


    Found in dry, open or shady places, Blue Fescue may appear bluer than plants around it.

    Spikelets are about 1/2" long. There's enough room between spikelets to see wavy branches.

    Spikelets are flattish, with 2-ranked florets. They're held close to the stem until mature. Awns are thread-like.
    Blue Gum
    Eucalyptus globulus
    • Height to 200 ft.
    • CA Bloom Oct - Mar
    • Flower nestled between stem and leaf.
    • Leaves long, thin and dark green.
    • Common, found in disturbed areas.
    • Not CA native
    • Somewhat Invasive


    Flower has many white stamens surrounding a central knob, and smells of honey.

    Mature leaves are narrow and curved, growing to a foot long. Woody fruits with 5 notches, grow to 1 inch across.

    Heavy trunks with bark that peals in large strips.
    Blue-Eyed Grass
    Sisyrinchium bellum
    • Height 1 - 2 ft.
    • CA Bloom Mar - May
    • This is not a grass but an iris.
    • At the top of each stem are violet flowers with darker purple lines leading to a yellow center.
    • It's common in open, usually moist areas.
    • CA native. Endemic to the California Floristic Province.



    Beautiful 1/2" wide flowers have blue to violet petals and a golden yellow center to guide pollinators in.

    Leaves are grass-like, narrow with parallel veins.

    The ovary is below the flower and, if pollinated, develops into a capsule-like fruit.
    Bog Yellowcress
    Rorippa palustris ssp. palustris
  • CA Bloom Apr - Jun
  • Yellow flower
  • Four petals
  • Alternate leaves
  • CA native




  • Box Elder
    Acer negundo
    • Height 25 - 66 ft.
    • CA Bloom Feb - Mar
    • Opposite leaves
    • Streambanks
    • CA native




    Bracken Fern
    Pteridium aquilinum var. pubescens
    • Bracken Fern's overall shape is a large triangle, which is easy to spot.
    • It's green in the spring and brown in the fall and winter.
    • It grows to four feet tall.
    • Widespread and common, it's found in shaded forest and on open hillsides.
    • CA native



    Bracken Fern frond segments are long at the base and quite short near the top, creating an overall triangle shape.

    Segments have regular rounded lobes. The similar Sword Fern has a "thumb" near its midrib.

    New growth forms in a fiddlehead, and then opens up.
    Branched Indian Clover
    Trifolium dichotomum
  • CA Bloom Mar - May
  • Black, brown, pink, white flower
  • Irreg petals
  • Alternate leaves
  • CA native




  • Branching Phacelia
    Phacelia ramosissima
  • CA Bloom May - Aug
  • Violet, white flower
  • Five petals
  • Alternate leaves
  • Coastal
  • CA native




  • Brewer's Ragwort
    Packera breweri
  • CA Bloom Apr - May
  • Yellow flower
  • Many petals
  • Alternate, basal leaves
  • Slopes
  • CA native




  • Brewer's Rock Cress
    Boechera breweri
  • CA Bloom Feb - May
  • Violet flower
  • Four petals
  • Alternate, basal leaves
  • Slopes
  • CA native




  • Brewer's Rockcress
    Boechera breweri ssp. breweri
  • CA Bloom Feb - May
  • Violet flower
  • Four petals
  • Alternate, basal leaves
  • CA native




  • Brewer's Saltbrush
    Atriplex lentiformis
  • CA Bloom Jun - Jul
  • Yellow flower
  • Tiny petals
  • Alternate leaves
  • Coastal salt-marsh
  • CA native




  • Bristly Linanthus
    Leptosiphon aureus
  • CA Bloom Mar - Jun
  • Pink, white, yellow flower
  • Five petals
  • Opposite leaves
  • CA native
  • Uncommon (CNPS 4)




  • Bristly Ox-Tongue
    Helminthotheca echioides
    • Height to 7 ft.
    • CA Bloom Jun - Dec
    • A tall dandelion-like flower, covered in bristles.
    • Leaves have large bumps on them.
    • Lots of seed in the fall - you'll see it blowing in the air.
    • Not CA native.
    • Somewhat Invasive


    Leaves have stiff bristles and bumps, giving it its name. Dandelion-like flowers top each branch.

    Dandelion-like flowers are surrounded by distinctive, triangular, upward pointing, bristly green bracts.

    Plants are tall, with many branches.
    Brittle Leaf Manzanita
    Arctostaphylos crustacea
    • Height 3 - 10 ft.
    • CA Bloom Jan - Mar
    • Leaves stick out from the hairy stem.
    • Alternate leaves dark green above, and light green below.
    • Big bunches of tiny flowers, hanging down from pedicels.
    • Fruit red, spherical with flat spot. Not sticky.
    • CA native



    Leaves are big - about 2 inches long. Clusters of tiny white flowers.

    Prominent burl at the base of the plant.

    Grows to 8 feet, generally in the fog belt.
    Brittle Leaf Manzanita (1)
    Arctostaphylos crustacea ssp. crustacea
    • Height 3 - 10 ft.
    • CA Bloom Jan - Mar
    • Leaves stick out from the hairy stem.
    • Alternate leaves dark green above, and light green below.
    • Big bunches of tiny flowers, hanging down from stalk-like pedicels.
    • Fruit is red and spherical with flat spot. Not sticky.
    • CA native



    Leaves are relatively big (2" long). Flowers are tiny in large bunches.

    Early flower development shows red bracts. Leaves of ssp. crustacea have almost no hair on the bottom.

    Look for a prominent burl at the base of the plant.
    Broad Leaf Lupine
    Lupinus latifolius var. latifolius
    • This perennial has an erect stem up to 4 feet tall.
    • CA Bloom Apr - May
    • Blue and purple flowers have a white banner spot that ages to magenta.
    • Found in dry rocky areas, this plant needs some shade and seasonal moisture.
    • CA native



    The inflorescence can get really tall - up to 2 feet long. Flowers have an open arrangement.

    Broad Leaf Lupine has broad leaves. They feel rubbery on top and slick underneath.

    Leaves (up to 4" for each finger on stalks up to 8" long) dwarf the individual 1/2" flowers.
    Broadfruit Bur Reed
    Sparganium eurycarpum
  • CA Bloom Jun - Jul
  • Black, brown, green, pink, white, yellow flower
  • Tiny petals
  • Alternate leaves
  • CA native




  • Brome Fescue
    Festuca bromoides


    Brome Fescue is a short grass with small spikelets that turn a straw-like color as they age. Fescue is Latin for "straw".

    Each floret produces an awn about the length of the rest of the spikelet.

    The inflorescence is densely populated with spikelets on short stalks. Spikelets and awns point sideways as they mature, giving a tangled appearance.
    Bulbous Blue Grass
    Poa bulbosa
    • Perennial 6-24"
    • Inflorescence branched 1-4"
    • No awns
    • CA Bloom May - Jun
    • Stems have a bulbous section at their base that can break off to form a new plant.
    • Some plants have bi-sexual florets. Others have aerial bulblets that are self pollinated.
    • Not CA native



    Most California plants have self-pollinated aerial bulblets with shoots already growing out of them.

    The base of the stem also has bulblets that divide to create new plants.

    This weedy bluegrass can dominate roadsides, overgrazed pastures and other disturbed areas.
    Bull Thistle
    Cirsium vulgare
    • CA Bloom June - Sept
    • This thistle has spiny everything.
    • A pear-shaped spiny base supports a 2-inch-tall purple flower.
    • Dead flowers with many spines stay on the plant for a long time.
    • Bull Thistle is common in disturbed areas.
    • Not CA native.
    • Moderately Invasive


    A fairly thin pear-shaped spiny bulge below flower is a good way to distinguish this species.

    Bull Thistle has big spines all the way up the stem, on the leaves, and around the flower.

    Here is a basal rosette of thick, toothed leaves.
    Bur Reed
    Sparganium eurycarpum var. greenei
  • CA Bloom Jun - Jul
  • Black, brown, green, pink, white, yellow flower
  • Tiny petals
  • Alternate leaves
  • CA native




  • California Aster
    Symphyotrichum chilense
  • CA Bloom Jul - Aug
  • Blue, pink, violet, white flower
  • Many petals
  • Alternate leaves
  • CA native




  • California Aster (1)
    Corethrogyne filaginifolia
  • CA Bloom Jun - Oct
  • Pink, violet, white flower
  • Many petals
  • Alternate leaves
  • Dunes coastal
  • CA native




  • California Bay Laurel
    Umbellularia californica
    • CA Bloom Nov - May
    • Height to 60 feet.
    • The foliage of this classic California tree smells like bay leaves.
    • Clusters of small flowers grow at the end of branches where new leaves emerge.
    • Flowers turn into a plump 1 inch fruit resembling avocados, to which the tree is related.
    • CA Native - endemic to the California Floristic Province.



    Leaves are fairly narrow, with a central vein and smooth edges, ending in a point. They have a leathery feel, and a spicy smell when crushed.

    Green fruit turns purple when mature. Leathery skin covers oily flesh that surrounds a pit (similar to avocado).

    Bay Laurels can grow to be substantial trees, thickly covered with their spicy-smelling leaves.
    California Bedstraw
    Galium californicum
  • CA Bloom Mar - Sep
  • Yellow flower
  • Four petals
  • Whorled leaves
  • CA native




  • California Blackberry
    Rubus ursinus
    • Height 3 - 6 ft.
    • CA Bloom Feb - May
    • This shrub forms an impenetrable thicket of branches, full of narrow prickles.
    • You'll notice bright white flowers with many stamens.
    • Found in canyons, coastal stream banks and disturbed areas
    • CA native



    Separate petals, with green leafy sepals in between. This male flower has many stamens.

    Prickles are short, narrow, and plentiful. Himalayan Blackberry has wider, longer, and less densely-packed prickles.

    Red fruit turns black with maturity. Leaves in 3s, coarsely toothed, are hairy and have spines. Veins are indented on the leaves.
    California Brome
    Bromus sitchensis var. carinatus


    Spikelets attach to the stem on branches. Glumes are short, revealing 5-10 florets above them.

    Florets form a flat, woven pattern, each with a 1/2" awn.

    Long leaves and inflorescences give this a classic bunch grass look.
    California Buckeye
    Aesculus californica
    • Height 12 - 40 ft.
    • CA Bloom May - Jul
    • Buckeye trees are conspicuous from afar; pale green leaves in early spring, full of flowers in early summer, and bare-branched well before other trees lose their leaves in the fall.
    • Each aromatic flower has 4 pink or white petals and long stamens.
    • The fruit resembles a buck's eye - brown and about 2 inches across.
    • CA native



    Buckeye trees become covered with columns of sweet-smelling flowers.

    5-part compound leaves are palmate (shaped like a hand). Leaf edges are finely-toothed and bud in early February.

    Trees in the open form a dome shape, often growing 40 feet tall and 40 feet wide. They can live 250 years.