''Clarkia franciscana'' is a rare species of flowering plant in the evening primrose family known by the common name Presidio clarkia. 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 ...

to the

San Francisco Bay Area The San Francisco Bay Area, commonly known as the Bay Area, is a List of regions of California, region of California surrounding and including San Francisco Bay, and anchored by the cities of Oakland, San Francisco, and San Jose, California, S ...

of California, where it is known only from two populations at the

Presidio of San Francisco The Presidio of San Francisco (originally, El Presidio Real de San Francisco or The Royal Fortress of Saint Francis) is a park and former U.S. Army post on the northern tip of the San Francisco Peninsula in San Francisco, California, and is part ...

and three occurrences in

Oakland Oakland is a city in the East Bay region of the San Francisco Bay Area in the U.S. state of California. It is the county seat and most populous city in Alameda County, with a population of 440,646 in 2020. A major West Coast port, Oakland is ...

.Center for Plant Conservation
The plant is known only from

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 ...

Distribution

''Clarkia franciscana'' is a federally listed

endangered species An endangered species is a species that is very likely to become extinct in the near future, either worldwide or in a particular political jurisdiction. Endangered species may be at risk due to factors such as habitat loss, poaching, inv ...

. The two San Francisco populations are on land which is protected from development but is affected by many other factors including invasive plant species, trampling, and

landscaping Landscaping refers to any activity that modifies the visible features of an area of land, including the following: # Living elements, such as flora or fauna; or what is commonly called gardening, the art and craft of growing plants with a goal ...

of vegetation. The three Oakland populations are probably the remnants of one population that was fragmented by development in the heavily altered urban habitat. The largest of the three occurrences is partially protected at

Redwood Regional Park Dr. Aurelia Reinhardt Redwood Regional Park (formerly known as Redwood Regional Park) is a part of the East Bay Regional Parks District (EBRPD) in the San Francisco Bay Area. It is located in the hills east of Oakland, California. The park conta ...

, but the other two are on privately owned property which is proposed to undergo some development. Construction of housing is proposed on the site, with less than an acre being left undeveloped as a compromise between developers and environmental advocates.Zamora, J. H
Dispute over flower: habitat vs. housing
''

San Francisco Chronicle The ''San Francisco Chronicle'' is a newspaper serving primarily the San Francisco Bay Area of Northern California. It was founded in 1865 as ''The Daily Dramatic Chronicle'' by teenage brothers Charles de Young and M. H. de Young, Michael H. ...

'' June 5, 2007

Description

The Presidio clarkia, ''Clarkia franciscana'', is an erect annual herb growing up to about 40 centimeters in maximum height. The leaves are narrowly lance-shaped and up to about 3.5 centimeters long. The top of the stem is occupied by 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 ...

, which bears opening flowers and closed, erect flower buds. The

sepal A sepal () is a part of the flower of angiosperms (flowering plants). Usually green, sepals typically function as protection for the flower in bud, and often as support for the petals when in bloom., p. 106 Etymology The term ''sepalum'' ...

s stay fused together as the petals bloom from one side. The small corolla is bowl-shaped, with petals up to 1.3 centimeters long and wedge-shaped with mostly flat tips. The petals are lavender-pink in color, darkest at the tips and lightening to nearly white at the base, where there is a deep red spot. The plant is

self-pollinating Self-pollination is a form of pollination in which pollen arrives at the Stigma (botany), stigma of a flower (in flowering plants) or at the ovule (in gymnosperms) of the same plant. The term cross-pollination is used for the opposite case, where ...

. The population sizes are variable from year to year; sometimes there are no plants seen at all, the seed banks remaining dormant until conditions improve.

References

External links

*
Jepson Manual Treatment of ''Clarkia franciscana''
* ttp://calphotos.berkeley.edu/cgi/img_query?query_src=photos_index&where-taxon=Clarkia+franciscana ''Clarkia franciscana'' — U.C. Photo gallery {{Taxonbar, from=Q5127548 franciscana Endemic flora of California Natural history of the California chaparral and woodlands Natural history of San Francisco Natural history of the San Francisco Bay Area Plants described in 1958