''Stellaria irrigua'' is a species of flowering plant in the family

Caryophyllaceae Caryophyllaceae, commonly called the pink family or carnation family, is a family (biology), family of flowering plants. It is included in the dicotyledon order Caryophyllales in the APG III system, alongside 33 other families, including Amaranth ...

known by the common names umbrella starwort and umbellate starwort. It is native to western North America from

Alaska Alaska ( ) is a non-contiguous U.S. state on the northwest extremity of North America. Part of the Western United States region, it is one of the two non-contiguous U.S. states, alongside Hawaii. Alaska is also considered to be the north ...

and north-western Canada to the south-western United States, as well as parts of Asia, including

Siberia Siberia ( ; , ) is an extensive geographical region comprising all of North Asia, from the Ural Mountains in the west to the Pacific Ocean in the east. It has formed a part of the sovereign territory of Russia and its predecessor states ...

. It grows in subalpine and

alpine climate Alpine climate is the typical climate for elevations above the tree line, where trees fail to grow due to cold. This climate is also referred to as a mountain climate or highland climate. Definition There are multiple definitions of alpine cli ...

s in mountain forests and riverbanks. It is a rhizomatous

perennial In horticulture, the term perennial ('' per-'' + '' -ennial'', "through the year") is used to differentiate a plant from shorter-lived annuals and biennials. It has thus been defined as a plant that lives more than 2 years. The term is also ...

herb Herbs are a widely distributed and widespread group of plants, excluding vegetables, with savory or aromatic properties that are used for flavoring and garnishing food, for medicinal purposes, or for fragrances. Culinary use typically distingu ...

producing a slender prostrate stem up to about 20 centimeters long, sometimes forming clumps or mats. The stem is lined with pairs of oval leaves each up to about 2 centimeters long. 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 an umbel-shaped array of several flowers each on an arching or erect pedicels. The flower has five pointed green

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 each no more than 3 millimeters long. There are occasionally tiny white petals within the calyx of sepals, but these are generally absent.

References

External links

Jepson Manual TreatmentFlora of North AmericaPhoto gallery
irrigua Flora of Subarctic America Flora of Western Canada Flora of the Northwestern United States Flora of the Southwestern United States Flora of the South-Central United States Taxa named by Alexander von Bunge {{Caryophyllaceae-stub