Chaparral Pea

Chaparral Pea © KKorbholz

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.
Flower © DSchiel
Pea Flower

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)

  • 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
  • No human uses found for this species

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
    • 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
Comparison of Leaves © DSchiel

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.

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. U.S. Department of Agriculture, Forest Service, Rocky Mountain Research Station, Fire Sciences Laboratory.

Prigge, B.A. and A.C. Gibson. 2016. Chaparral Pea – Pickeringia montana var. montana. Santa Monica Mountains National Recreation Area.

Stebbins, G.L. and J. Major. 1965. Endemism and speciation in the California flora. Ecological Monographs 35.2: 2–35.

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.