Rosaceae (Rose Family)

The large and diverse Rosaceae is diffcult to define precisely - particularly variable are the pistil and fruiting arrangement - so this will limit itself to the characteristics of the wild varieties found in the area. The features of the common local genera can be easily identified: Rubus (blackberries and raspberries), Fragaria (strawberries), Rosa (roses), and Potentilla (cinquefoils). With a few additions, most of the wild members of Rosaceae fall into one of these families.

The leaves on these plant are alternate, although the leaflets are usually opposite. The leaves often have stipules (paired appendages at the base, sometimes as large as regular leaves). The calyx has 5 lobes, and there are either 5 petals or none, at least 15 stamens, and one-to-many pistils. The one-seeded fruit may be dry or fleshy, separate or bunched (as in blackberries).

Rosaceae is a strong component of the mountains native habitats, and one will often find areas populated by almost nothing but members of this family - groupings of cream bush, toyon, cinquefoil, horkelia, blackberry, thimbleberry and strawberries are quite common.

The many members of Rosaceae on Montara Mountain include:

Cotoneaster sp.
Cotoneaster

Fragaria chiloensis
Beach Strawberry

Fragaria vesca
Wood Strawberry

Heteromeles arbutifolia
Toyon Bush

Holodiscus discolor
Cream Bush

Horkelia californica
California Horkelia

Oemleria cerasiformis
Oso Berry

Potentilla anserina
ssp. pacifica
Pacific Cinquefoil

Potentilla glandulosa
Sticky Cinquefoil

Potentilla hickmanii
Hickman's Cinquefoil

Rosa gymnocarpa
Wild Rose

Rubus parviflorus
Thimbleberry

Rubus spectabilis
Salmonberry

Rubus ursinus
California Blackberry

 


 

Oemleria cerasiformis:
Oso Berry

Rosaceae (Rose Family)

Flowers: White, 5 distinct petals, in hanging clusters along new branches. Male and female on separate trees.

Blooms: March - April

Leaves: Elliptical, 2 to 4 inches long, wooly on the underside, smooth-margined; deciduous.

Fruit/Seeds: Green/orange fruit, sometimes turning blue-black before falling, in small clusters among branches.

Location: In shaded areas of creek canyons.

Status: Native - Uncommon

Oemleria cerasiformis
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Further description & Comment: Tall shrub/small tree, 5 - 15 feet tall.

Osoberry may be more common than I realize, but because it tends to grow discreetly in riparian thickets, it's hard to find. The one pictured here grows along Martini creek, and produces fruit each year (lower left), so there must be another nearby.


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Potentilla anserina
ssp. pacifica:
Pacific Cinquefoil

Rosaceae (Rose Family)

Flowers: Yellow, 5 distinct petals with alternate bract-like sepals, on single stems from base of plant.

Blooms: April - August.

Leaves: Pinnate, long and feather like;15 to 31 leaflets; bright green on top and whitish-hairy below.

Fruit/Seeds: ??

Location: Wet areas everywhere on the mountain.

Status: Native - Common

Potentilla anserina
ssp. pacifica
600x450 JPEG - 28K

Further description & Comment: 6 to 18 inches tall; growing in large masses in wet areas and edges of salt marshes. Spreads by bright red strawberry-like runners. Image at lower left shows a detail of the leaves.

In the late spring, low wet areas around the mountain are just packed with P. anserina. as seen in the image below right.


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Potentilla glandulosa:
Sticky Cinquefoil

Rosaceae (Rose Family)

Flowers: White (may be tinged light yellow), 5 oval petals, small; many stamens in bright yellow center; in loose clusters at top of stem.

Blooms: May - August.

Leaves: Pinnate, with 5 - 9 strongly toothed leaflets.

Fruit/Seeds: ??

Location: All areas of the mountain - very common.

Status: Native - Common


Potentilla glandulosa
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600x450 JPEG - 48K

Further description & Comment: 1 to 3 feet tall, erect plants. The stems of P. glandulosa are very sticky with glandular hairs, hence the name. This makes it easy to differentiate from Pacific Cinquefoil (P. anserina ssp. pacifica), which usually grows only in very wet habitats.

Sticky Cinque does resemble California Horkelia enough to confuse and frustrate, especially when the plants are not flowering. The stickiness of the plant stems is the most reliable way to tell them apart. In general, Sticky has fewer lobes on the leaflets, rounder petals, and blooms earlier in the spring.

 


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