''Ravenella exigua'', the chaparral bellflower, rock harebell, or Rattan campanula, is an annual

flowering plant Flowering plants are plants that bear flowers and fruits, and form the clade Angiospermae (). The term angiosperm is derived from the Ancient Greek, Greek words (; 'container, vessel') and (; 'seed'), meaning that the seeds are enclosed with ...

in the bellflower family

Campanulaceae The family Campanulaceae (also bellflower family), of the order Asterales, contains nearly 2400 species in 84 genera of herbaceous plants, shrubs, and rarely small trees, often with milky sap. Among them are several familiar garden plants bel ...

Distribution

The plant is

endemic Endemism is the state of a species being found only in a single defined geographic location, such as an island, state, nation, country or other defined zone; organisms that are indigenous to a place are not endemic to it if they are also foun ...

Mount Diablo Mount Diablo is a mountain of the Diablo Range, in Contra Costa County, California, Contra Costa County of the eastern San Francisco Bay Area in Northern California. It is south of Clayton, California, Clayton and northeast of Danville, Califo ...

, in the northern

Diablo Range The Diablo Range is a mountain range in the California Coast Ranges subdivision of the Pacific Coast Ranges in northern California, United States. It stretches from the eastern San Francisco Bay Area at its northern end to the Salinas Valley a ...

within

Contra Costa County Contra Costa County (; ''Contra Costa'', Spanish language, Spanish for 'Opposite Coast') is a U.S. county, county located in the U.S. state of California, in the East Bay of the San Francisco Bay Area. As of the 2020 United States census, the ...

, in the East Bay region of northern

California California () is a U.S. state, state in the Western United States that lies on the West Coast of the United States, Pacific Coast. It borders Oregon to the north, Nevada and Arizona to the east, and shares Mexico–United States border, an ...

. As its common name suggests, chaparral bellflower is a member of the

chaparral Chaparral ( ) is a shrubland plant plant community, community found primarily in California, southern Oregon, and northern Baja California. It is shaped by a Mediterranean climate (mild wet winters and hot dry summers) and infrequent, high-intens ...

ecosystem, growing primarily in

serpentine soil Serpentine soil is an uncommon soil type produced by weathered ultramafic rock such as peridotite and its metamorphic derivatives such as serpentinite. More precisely, serpentine soil contains minerals of the serpentine subgroup, especially an ...

s at elevations of . It grows amongst other Mount Diablo and regional endemic plants, all dependent on natural

fire ecology Fire ecology is a scientific discipline concerned with the effects of fire on natural ecosystems. Many ecosystems, particularly prairie, savanna, chaparral and coniferous forests, have evolved with fire as an essential contributor to habitat vit ...

conditions.

Description

''Ravenella exigua'' sends up several long stems filled with milky sap and bearing sparse, tiny leaves. At the end of each stem grows a bell-shaped bright blue-violet flower. The bloom period is May and June.

References

External links

Calflora Database: ''Campanula exigua'' (Chaparral harebell)Jepson Manual eFlora (TJM2) treatment of ''Campanula exigua'' U.C. Photos gallery of ''Campanula exigua''
Campanuloideae Endemic flora of California Mount Diablo Natural history of the California chaparral and woodlands Natural history of the California Coast Ranges Natural history of Contra Costa County, California Endemic flora of the San Francisco Bay Area Plants described in 1886 {{Campanulaceae-stub