''Ivesia longibracteata'' is a rare species of flowering plant in the

rose family Rosaceae (), the rose family, is a medium-sized family of flowering plants that includes 4,828 known species in 91 genera. The name is derived from the type genus ''Rosa''. Among the most species-rich genera are ''Alchemilla'' (270), ''Sorbus' ...

known by the common names Castle Crags ivesia and longbract mousetail. It is

endemic Endemism is the state of a species being found 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 found elsew ...

Shasta County, California Shasta County (), officially the County of Shasta, is a County (United States), county 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 the 2010 c ...

, 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 (phaneritic) 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 cools and solidifies undergro ...

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, needlel ...

Description

''Ivesia 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 An inflorescence is a group or cluster of flowers arranged on a stem that is composed of a main branch or a complicated arrangement of branches. Morphologically, it is the modified part of the shoot of seed plants where flowers are formed o ...

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