''Clarkia australis'' is a species of flowering plant in the evening primrose family known by the common name Small's southern clarkia. 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 els ...

California California is a state in the Western United States, located along the Pacific Coast. With nearly 39.2million residents across a total area of approximately , it is the most populous U.S. state and the 3rd largest by area. It is also the ...

, where it grows in the forests of the central

Sierra Nevada The Sierra Nevada () is a mountain range in the Western United States, between the Central Valley of California and the Great Basin. The vast majority of the range lies in the state of California, although the Carson Range spur lies primari ...

. It is an uncommon species threatened by such forest activities as logging. This annual herb produces a slender, erect stem approaching a meter in height. The leaves are widely linear in shape and borne on short petioles. The top of the stem is occupied by the tall

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 ...

, which bears hanging buds that open from the lowest upward so that there are several closed buds above open flowers. 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 The term ''sepalum'' was coined ...

s do not remain fused as the flower opens. The petals are diamond-shaped and sometimes lobed and curling at the tip. They are mottled or spotted lavender, purple, and reddish in color, and each is up to 1.5 centimeters long. There are 8 long

stamen The stamen (plural ''stamina'' or ''stamens'') is the pollen-producing reproductive organ of a flower. Collectively the stamens form the androecium., p. 10 Morphology and terminology A stamen typically consists of a stalk called the filam ...

s tipped with large anthers bearing blue-gray pollen. The stigma protrudes past the anthers. This species of ''

Clarkia ''Clarkia'' is a genus within the flowering plant family Onagraceae. Over 40 species are currently classified in ''Clarkia''; almost all are native to western North America, though one species (''Clarkia tenella'') is native to South America. ...

'' is very closely related to ''

Clarkia virgata ''Clarkia virgata'' is a species of flowering plant in the evening primrose family known by the common name Sierra clarkia. It is endemic to California, where it is known from the forests and woodlands of the Sierra Nevada. Description This is ...

'', and it has been suggested that it is not actually a separate species, but hybridization studies have demonstrated that there has been sufficient

reproductive isolation The mechanisms of reproductive isolation are a collection of evolutionary mechanisms, behaviors and physiological processes critical for speciation. They prevent members of different species from producing offspring, or ensure that any offsprin ...

to produce hybrid incompatibility between the two taxa, confirming that they should be treated as separate species.Gottlieb, L.D. & V.S. Ford. (1999). The status of ''Clarkia australis'' (Onagraceae). ''Am J Bot'' 86:428-435

References

External links

Jepson Manual ProfilePhoto gallery
Flora of California australis Plants described in 1971 {{Myrtales-stub