''Ceanothus bolensis'', the Cerro Bola ceanothus, is a rare species of ''

Ceanothus ''Ceanothus'' is a genus of about 50–60 species of nitrogen-fixing shrubs and small trees in the buckthorn family (Rhamnaceae). Common names for members of this genus are buckbrush, California lilac, soap bush, or just ceanothus. ''"Ceanothus" ...

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 ...

to extreme northwestern

Baja California Baja California, officially the Free and Sovereign State of Baja California, is a state in Mexico. It is the northwesternmost of the 32 federal entities of Mexico. Before becoming a state in 1952, the area was known as the North Territory of B ...

. It is named after Cerro Bola, a metavolcanic peak where the species is especially common and was first described from.

Description

''Ceanothus bolensis'' is a shrub growing approximately 1-1.5m in height and lacking a basal

burl A burl (American English) or burr (British English) is a tree growth in which the grain has grown in a deformed manner. It is commonly found in the form of a rounded outgrowth on a tree trunk or branch that is filled with small knots from d ...

. It has small, smooth and hairless, yellowish-green leaves and is not

deciduous In the fields of horticulture and botany, the term deciduous () means "falling off at maturity" and "tending to fall off", in reference to trees and shrubs that seasonally shed Leaf, leaves, usually in the autumn; to the shedding of petals, aft ...

. Flowers are pale blue to cream white. It is most similar visually to the nearby '' Ceanothus otayensis'' found further north, with which it does not overlap in range.Boyd, Steve, and Jon E. Keeley. "A new Ceanothus (Rhamnaceae) species from northern Baja California, Mexico." ''Madroño'' (2002): 289-294. https://www.jstor.org/stable/pdf/41425479.pdf

Distribution and habitat

''Ceanothus bolensis'' is extremely range restricted and was originally described as being endemic to the mid-to-high elevations of Cerro Bola peak, but is now known from a handful of other mountains in northwestern Baja California between Ensenada and

Tijuana Tijuana is the most populous city of the Mexican state of Baja California, located on the northwestern Pacific Coast of Mexico. Tijuana is the municipal seat of the Tijuana Municipality, the hub of the Tijuana metropolitan area and the most popu ...

. It occurs at elevations higher than approximately 500m, where it grows in

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 ...

habitat on metavolcanic soils.

References

{{Taxonbar, from=Q15534138 bolensis Endemic flora of Mexico Plants described in 2002 Flora of Baja California