Lathyrus vestitus var. vestitus
- Eudicots are a major lineage of flowering plants; see family for general characteristics
- Pea / Legume Family (Fabaceae)
- Climbing, herbaceous perennial, with tendrils
- Stems are 3-sided (triangulate in cross-section), often sharply-edged or flanged
- Compound (divided into leaflets) and pinnate (arranged along a common axis, like a feather)
- 8-12 grey-green leaflets end in one or more coiling tendrils, which anchor the plant
- Prominent arrow-shaped stipules (a pair of leaf-like structures at the base of the leaf stalk), with wavy edges
- Inflorescence (flower arrangement) of up to 15 flowers in a raceme (unbranched stem with stalked flowers opening from the bottom up)
- Characteristic Pea / Legume family flower is bilaterally-symmetric with a banner, wings, and keel
- Banner, bent upward at about 90o; is light violet, lavender, or whitish, with purple lines (nectar guides)
- Wings are pale violet to white
- Keel, partly hidden by the wings, is white
- Ovary superior (above the attachment of other flower parts)
- Fruit is a pea pod, a kind of legume (a single-chambered seed pod that opens along 2 seams)
- Height to 28 in.
- Native to California
- Outside California, grows from Oregon south to the Mexican border
- Grows at elevations to 4,900 ft.
Uses (San Mateo County Parks prohibits removal of any natural material)
- Frequented by insects (primarily large bees) and hummingbirds for nectar
- Host plant for the larval stage of silvery blue (Glaucopsyche lygdamus) and northern cloudywing (Thorybes pylades) butterflies
- Native people had several uses for common Pacific pea
- Ate raw seeds and greens
- Made a decoction of roots for use as a general medicinal remedy
- CAUTION – The fruits of many members of this genus contain a potent neurotoxin, which if not properly treated, can cause paralysis (Nature Collective 2020); best to avoid eating any wild peas
- Laythrus (LA-thi-rus) – from the Greek lathyros, “pea”
- vestitus (ves-TIE-tus) – from the Latin for “covered” or “clothed,” referring to hairs
- Like almost all members of its family, common pacific pea fixes nitrogen; see Pea / Legume family for more details
- Each flower part plays a role in insect pollination (Broich 1983)
- Banner petals have red lines, called nectar or floral guides, directing insects to pollen and/or nectar; some floral guides are invisible to the human eye unless viewed with ultraviolet light
- Wing petals are the “landing platforms” for pollinators
- Anthers (pollen-producing part of the stamen/male structure) and stigma (pollen-receiving part of the pistil/female structure) are hidden in the keel
- To get access, pollinators must be heavy enough to depress the wing-keel, pushing the stigma between the keel petals
- Pollen grains in the keel are “brushed” out by the stigma’s hairs as the stigma moves forward to make contact with the insect
- Flowers fade to yellow-brown and remain on the stem
- Genus includes the garden sweet pea (L. odoratus), native to southern Europe
- Edgewood’s common Pacific pea is classified as a variety
- Subspecies rank is used to recognize geographic distinctiveness, whereas variety rank is appropriate for variants seen throughout the geographic range of the species; in practice, these two ranks are not distinct
- May be confused with the several vetch (Vicia) species at Edgewood, including native American vetch (Vicia americana ssp. americana) and non-native spring vetch (Vicia sativa ssp. sativa)
|Common Pacific Pea2||American Vetch||Spring Vetch|
|New Leaves||rolled like a cigar||flat||closed like a book|
| Stipules |
(pair of leaf-like structures at base of leaf stalk)
|large (≤ 0.7 in.) and wavy-edged||small (~0.1 in.), star-like, with 3 teeth on lower half||small and toothed, with a dark-red dot|
|Cluster||up to 15 flowers on a long raceme3||3-5 flowers on a long raceme3||1-2 flowers at junction with stem|
|Color||pastels; pale lavender to purple, fading to yellow-brown||dark purple banner; wings and keel pale purple to white||dark pink-purple|
|Banner Angle||bent up at 90°||bent up at less than 90°||bent up at less than 90°|
(pollen-receiving part of pistil/female structure)
|hairs on one side||hairs all around||hairs all around|
2 You can associate the pea, like its homophone, with bathroom items, i.e. toothbrush (stigma) and toilet paper (rolled leaves)
3 Raceme – an unbranched flower cluster with short, equal stalks
- Found in woodlands
- See iNaturalist for observations of Lathyrus vestitus
- Flowers March – May
Broich, S.L. 1983. A systematic study of Lathyrus Vestitus Nutt. ex T. & G. (Fabaceae) and allied species of the Pacific Coast. Dissertation. Oregon State University, Corvallis, Oregon.
Mason, J. 2004. Common Pacific Pea and American Vetch stigma illustrations, adapted. In T. Corelli, Flowering Plants of Edgewood Natural Preserve, 2nd. ed. Monocot Press, Half Moon Bay, California. (c) CC BY NC 3.0.
Mitchell. M. 2017. Fabaceae: Pea Family — Vicia (Vetch). Monterey County Wildflowers, Trees, & Ferns – A Photographic Guide.
Nature Collective. 2020. Chaparral Sweet Pea.
Prigge, B.A. and Gibson, A.C. 2013. Lathyrus vestitus var. vestitus. A Naturalist’s Flora of the Santa Monica Mountains and Simi Hills, California. Web version, hosted at Wildflowers of the Santa Monica Mountains National Recreation Area. National Park Service. US Department of Interior.
Safford, H.D. and Miller, J.E.D. 2020. An Updated Database of Serpentine Endemism in the California Flora. Madroño, 67(2), pp. 85-104.