''Potentilla longibracteata'', also known as Castle Crags ivesia and longbract mousetail, is a rare species of flowering plant in the

rose family Rosaceae (), the rose family, is a family of flowering plants that includes 4,828 known species in 91 genera. The name is derived from the type genus ''Rosa''. The family includes herbs, shrubs, and trees. Most species are deciduous, but some ...

. 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 ...

Shasta County, California Shasta County (), officially the County of Shasta, is a County (United States), county located in the Northern California, northern portion of the U.S. state of California. Its population is 182,155 as of the 2020 census, up from 177,223 from t ...

, where it is known only from

Castle Crags Castle Crags is a dramatic and well-known rock formation in Northern California. Elevations range from along the Sacramento River near the base of the crags, to over at the summit of the tallest crag. Located just west of Interstate 5, betwe ...

. It grows in rocky

granite Granite ( ) is a coarse-grained (phanerite, phaneritic) intrusive rock, intrusive igneous rock composed mostly of quartz, alkali feldspar, and plagioclase. It forms from magma with a high content of silica and alkali metal oxides that slowly coo ...

habitat in the

temperate coniferous forest Temperate coniferous forest is a terrestrial biome defined by the World Wide Fund for Nature. Temperate coniferous forests are found predominantly in areas with warm summers and cool winters, and vary in their kinds of plant life. In some, needle ...

Description

''Potentilla longibracteata'' is a perennial herb forming a glandular green tuft of foliage where it grows from crevices in granite rock. The leaves are 2 to 4 centimeters long and are made up of several pairs of lobed leaflets. 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 headlike cluster of several flowers 1 or 2 centimeters wide. Each flower is just under a centimeter long and has tiny pale yellow petals.

References

External links

Jepson Manual Treatment — ''Ivesia longibracteata''''Ivesia longibracteata'' — Photo gallery
longibracteata Endemic flora of California Natural history of Shasta County, California ~ Plants described in 1989 {{Rosaceae-stub