California Native Plant Society
San Gabriel Mountains Chapter

West Fork of the San Gabriel River

The West Fork of the San Gabriel River rises near Red Box Gap, where the Mt. Wilson Road leaves the Angeles Crest Highway, and flows almost directly eastward through a deep valley that is one of the most picturesque locations in the entire San Gabriel Mountains. It's eastern extremely is followed closely by a road extending from a turn-off on Highway 39 all the way to the Cogswell Dam, approximately 8 miles, much of that distance being within the riverine environment of leafy trees and shade. The road is primarily for access to the dam, has never been open to the general public although it is freely accessible by bicycle or on foot. It's well worth visiting at different times of the year to see the variation in colors. This is Hike 71 in John Robinson's book Trails of the Angeles.

There are two panels of images: A. In the Fall, B. In the Winter
Click on the thumbnails to see higher-resolution images, 720 x 480 pixels.

A. IN THE FALL - a place to see fall colors

San Gabriel River Douglas Fir Sycamore Bigleaf maple River in alder forest

West Fork of the
San Gabriel River

Big cone Douglas fir (Pseudotsuga macrocarpa) on a slope above the river valley

Fall color
California sycamore
(Platanus racemosa)

More fall color:
Bigleaf maple
(Acer macrophyllum)

San Gabriel River in a tunnel of alder forest

Ash seeds
Ash grove
Golden back fern
Alder trees
Alder leaves

Velvet ash (Fraxinus velutina)
A mass of seeds (L), a grove of trees (R)

Goldenback fern (Pentagramma triangularis ssp. triangularis)

Alder (Alnus rhombifolia)
a grove of trees (L), and leaves together with both previous year's and current year's fruit.
The alder grows in damp ground along the stream.

Nilkweed caterpillar Milkweed bug Painted lady West coast lady

Monarch caterpillar (L) and milkweed bug (R) on narrowleaf milkweed (Asclepius fascicularis)

Painted lady (L) and West Coast Lady (R)

Propertius duskywing

Hollyleaf redberry
River in alder forest

Reflections in the
San Gabriel River

A buckwheat (Eriogonum elongatum)

Hollyleaf redberry (Rhamnus ilicifolia)

San Gabriel River

  Maple trees The river    

Fall color: Alder trees (Alnus rhombifolia)

San Gabriel River in a tunnel of alder trees


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B. IN THE WINTER - mostly ferns

West Fork of the San Gabriel River

Alder trees (Alnus rhombifolia) by the river

Road along the river

Goldenback fern
(Pentagramma triangularis ssp. triangularis)

Coffee fern
(Pellaea andromedifolia)

California polypody
(Polypodium californicum)

Bigelow's spikemoss (Selaginella bigelovii)

Probably young incense cedar

Two liverworts, Targionia hypophylla (L) and Astrella californica (R)

Coastal wood fern (Dryopteris arguta), showing its association with the oak tree


Southern maidenhair fern
(Adiantum capillus-veneris)

“Weeping wall” of maidenhair fern

Birdsfoot fern (Pellaea mucronata var. mucronata)

Milkmaids (Cardamine california var. californica)


Round-leafed boykinia (Boykinia rotundifolia)

Bigberry manzanita (Arctostaphylos glauca)

A comparison: The river in November 2008 (L) and in February 2009 (R) following winter wind storms

Reflections in the San Gabriel River

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Images copyright © 2008-2009 Mary and Graham Bothwell.
Thanks to Jane Strong for assistance in identification of plants and flowers.