Oxalidaceae (Wood Sorrel Family)

Wood Sorrels are a familiar family, altho most of the species found thoughout the Bay Area are alien invasives. Members of Oxalidaceae are characterized by 3-lobed clover-like leaf blades, and by fleshy underground rhizomes. The flowers have a 5 lobed calyx, and 5 separate petals that overlap in a twisted form in the bud. The petals may also form a tube when the plant closes, which many do at night.

There are only two native species of Oxalidaceae in the Bay Area, and only one of these, Oxalis albicans pilosa (Hairy Wood Sorrel) occurs on Montara Mountain. The other family member found on the mountain is the too-familar alien Oxalis pes-capre (Bermuda Sorrel or Sour Grass), that is responsible for the vast fields of flourescent yellow-green flowers seen from mid winter to early spring throughout the coast.



Oxalis pes-capre:
Bermuda Sorrel (Sour Grass)

Oxalidaceae (Wood Sorrel Family)

Flowers: Yellow to Yellow-Green, funnel shaped flowers on tall leafless stems - flowers close in evening, or if it gets dark and cold.

Blooms: November - July.

Leaves: Clover like, three double-lobed, creased, dark=spotted leafs on top of stem.

Fruit/Seeds: Small bulblike structures both above and below ground.

Location: Everywhere, lower elevations in disturbed areas, farm fields, lawns, along roadsides, etc.

Oxalis pes-capre

600 x 450 JPEG - 64K

Status: Alien - Invasive: Nearing out-of-control status.

Further description & Comment: Sprawling mats, growing in creeping colonies, often covering huge open areas with bright flourenscent yellow-green blooms in winter. As any gardener will attest, the only way to get this stuff out of an area is to remove it along with the top 4 inches of soil, so you collect the numerous, tiny bulb-like structures the plants produce that they propagate from.

This pile of dirt and trash was dumped in McNee Ranch State Park years ago, and blooms each winter and spring with a variety of aliens and garden escapees, including our friend Oxalis pre-capre.


Return to Orchidaceae (Orchid Family)

Continue to Papaveraceae (Poppy Family)

  Plant Listings by: Family & Latin Name Common Name Color
Top of Page     Home