''Ceanothus masonii'' is a species of

shrub A shrub or bush is a small to medium-sized perennial woody plant. Unlike herbaceous plants, shrubs have persistent woody stems above the ground. Shrubs can be either deciduous or evergreen. They are distinguished from trees by their multiple ...

in the buckthorn family,

Rhamnaceae The Rhamnaceae are a large Family (biology), family of flowering plants, mostly trees, shrubs, and some vines, commonly called the buckthorn family. Rhamnaceae is included in the order Rosales. The family contains about 55 genera and 950 specie ...

, known by the common name Mason's ceanothus. It 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 ...

Marin County, California Marin County ( ) is a County (United States), county located in the northwestern part of the San Francisco Bay Area of the U.S. state of California. As of the 2020 United States census, 2020 census, the population was 262,231. Its county seat a ...

, where it is known only from an area near Bolinas on the

Point Reyes National Seashore Point Reyes National Seashore is a park preserve located on the Point Reyes, Point Reyes Peninsula in Marin County, California. As a national seashore, it is maintained by the US United States National Park Service, National Park Service as an ...

. It grows in the coastal

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 ...

on the windblown bluffs..

Description

This rare shrub grows to heights approaching 2 meters. The evergreen leaves are oppositely arranged and less than 2 centimeters long. They are round to oval in shape and have tiny, sharp teeth along the edges, sometimes spine-tipped. The

inflorescence In botany, an inflorescence is a group or cluster of flowers arranged on a plant's Plant stem, stem that is composed of a main branch or a system of branches. An inflorescence is categorized on the basis of the arrangement of flowers on a mai ...

is a small cluster of deep blue to purple flowers. The fruit is a capsule just a few millimeters wide, topped with minute horns. This ceanothus is closely related to '' Ceanothus gloriosus'', and may in fact be a variety of that species.California Native Plants Society Rare Plants Inventory
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References

External links

Jepson Manual Treatment of ''Ceanothus masonii''

USDA Plants Profile for ''Ceanothus masonii''

''Ceanothus masonii'' — U.C. Photo gallery
masonii Endemic flora of California Natural history of the California chaparral and woodlands Natural history of Marin County, California West Marin Plants described in 1942 Endemic flora of the San Francisco Bay Area {{Rhamnaceae-stub