Chaparral Pea :

Pickeringia montana var. montana
NATIVE – CA ENDEMIC

Description (Jepson, PlantID.net)

Eudicotyledon
- Eudicots are a major lineage of flowering plants; see family for general characteristics
Pea Family (Fabaceae)
- Only species in its genus (monotypic)
Evergreen shrub
- Forms dense thickets
- Grows predominately from rhizomes
Branches tipped by a thorn (sharp-pointed modified stem)
Leaves
- Alternate (1 leaf at each junction with stem) and compound (divided into leaflets)
  - Usually clustered in groups of 2-3 leaflets
- Sclerophyllous (“hard leaf”; see Adaptations below)
  - Small, waxy, densely organized, elliptic to ovate
Flowers
- Inflorescence (flower arrangement) is a raceme (unbranched stem with stalked flowers opening from the bottom up) of magenta pea flowers
- Characteristic Pea family flower is bilaterally-symmetric, with a banner, wings, and keel
  - Banner is prominent and spreading, with gold-brown markings at base
  - 2 small wings with irregular edges project forward
  - 2 petals of keel are small and unfused
- Ovary superior (attached above other flower parts)
Fruit is a legume (a single-chambered seed pod that opens along 2 seams), seldom produced
Height to 10 ft.

Distribution

Native and endemic (limited) to California
- Grows in chaparral and open woodlands
- See Calflora for statewide observations of this plant
Grows at elevations to 2,165 ft.

Uses (San Mateo County Parks prohibits removal of any natural material)

Wildlife
- Deer browse leaves and flowers (Howard 1992)
- Hummingbirds frequent flowers for nectar, as do several species of butterfly, e.g., marine blue (Leptotes marina), gray hairstreak (Strymon melinus), and rural skipper (Ochlodes agricola) (EOL)
- Dense thickets provide habitat for birds and mammals

Name Derivation

Pickeringia (pik-er-IN-jee-a) – named in honor of Charles Pickering (1805-1878), physician and botanist of the Philadelphia Academy of Sciences, who explored California as a member of the Wilkes Expedition (1838-1842) and whose collections were some of the founding collections of the Smithsonian Institution
montana (mon-TAY-na) – from the Latin for “of the mountains”

Adaptations

Component of California chaparral
- Chaparral refers to evergreen shrub and small tree communities that grow on shallow, rocky, nutrient-poor soils in Mediterranean climates, with mild, wet winters and hot, dry summers
- Chaparral shrubs, like chaparral pea, are examples of sclerophyllous (“hard-leaf”) vegetation, with leaves that conserve water by being
  - Thick and leathery, with extra lignin (structural component that stiffens plant tissue) to prevent wilting
  - Waxy, with a thick cuticle that reduces transpiration
  - Densely organized, occurring at short distance along the stem, thus increasing local humidity
  - Usually small and oriented parallel or oblique to direct sunlight, reducing surface exposure
A symbiotic relationship with nitrogen-fixing bacteria allows chaparral pea to grow in nitrogen-poor soils; see Pea family for details
Regenerates following fire or disturbance by sprouting from the root crown
- Although seed pods may form, plant rarely reproduces by seed
- Mixed chaparral communities would have burned frequently in the past (Howard 1992)
Chaparral pea has thorns, rather than spines or prickles, which help deter herbivory
- True thorns are sharp-pointed modified stems, as on citrus trees
- Spines are sharp-pointed modified leaves, as on cacti and at Edgewood on gooseberries, or leaf parts, as on leather oaks
- Prickles grow from the outer layers (epidermis) of plant stems, as on blackberries

Notes

One of very few native legumes (Pea-family members) in the chaparral habitat
An example of a California paleoendemic (Wojciechowski 2013)
- A paleoendemic is a relatively old, relict species, e.g. coast redwoods and Monterey pines, now restricted from an originally larger geographic distribution (Stebbins 1965)
- California’s complex geological, topographic, and climatic history favored the creation of refugias, protected pockets for some ancient lineages (Baldwin 2014)
  - California has more paleoendemics than any other state or province in North America
- Western Leatherwood (Dirca occidentalis) and California Bay (Umbellularia californica) are two examples of paleoendemics in Edgewood
Edgewood’s chaparral pea is classified as a variety
- Variety indicates a population with small morphological variations, e.g. color, seen throughout the geographic range of the species; interbreeding is possible
- Subspecies indicates a geographically-separated population with distinct morphological characteristics; when not isolated, interbreeding is possible
- In practice, botanists have not consistently applied these ranks

ID Tips

May be confused with buckbrush (Ceanothus cuneatus) in the Buckthorn family when not blooming
- Chaparral pea
  - Leaves are alternate (1 leaf at each junction with stem) and compound (divided into leaflets), usually with 3 leaflets
  - Leaves shiny green on top
  - Branches have a terminal thorn
- Buckbrush
  - Leaves are opposite (2 leaves at each junction with stem) and simple (not divided into leaflets)
  - Leaves dull green on top
  - Branches lack a terminal thorn

At Edgewood

Found in chamise chaparral
- Most frequently seen off upper Clarkia trail, between trail posts 21 – 22
- See iNaturalist for observations of this plant
Flowers May – July

See General References

Specific References

Baldwin, B.G. 2014. Origins of plant diversity in the California Floristic Province. Annual Review of Ecology, Evolution, and Systematics 45: 347-69.

Elpel, T.J. 2013. Pea family – Fabaceae [Illustration of pea subfamily, adapted]. Botany in a Day: The Patterns Method of Plant Identification. HOPS Press, Pony, Montana.

EOL (Encyclopedia of Life). Chaparral pea. National Museum of Natural History, Smithsonian. Accessed 9 March 2022.

Howard, J.L. 1992. Pickeringia montana. Fire Effects Information System. United States Department of Agriculture, Forest Service, Rocky Mountain Research Station, Fire Sciences Laboratory.

Prigge, B.A. and A.C. Gibson. 2016. Pickeringia montana var. montana. 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. United States Department of Interior, National Park Service.

Stebbins, G.L. and J. Major. 1965. Endemism and speciation in the California flora. Ecological Monographs 35: 2–35. JSTOR.

Wojciechowski, M.F. 2013. The origin and phylogenetic relationships of the Californian chaparral ‘Paleoendemic’ Pickeringia (Leguminosae). Systematic Botany 38(1): 132-142. American Society of Plant Taxonomists. JSTOR.