''Juncus capitatus'' is a species of rush known by the common names dwarf rush and leafybract dwarf rush. It is native to Europe, Asia and North Africa. It is also an

introduced species An introduced species, alien species, exotic species, adventive species, immigrant species, foreign species, non-indigenous species, or non-native species is a species living outside its native distributional range, but which has arrived ther ...

in parts of North America such as

California California () is a U.S. state, state in the Western United States that lies on the West Coast of the United States, Pacific Coast. It borders Oregon to the north, Nevada and Arizona to the east, and shares Mexico–United States border, an ...

and the

Gulf Coast The Gulf Coast of the United States, also known as the Gulf South or the South Coast, is the coastline along the Southern United States where they meet the Gulf of Mexico. The coastal states that have a shoreline on the Gulf of Mexico are Tex ...

. It grows in moist areas, such as wet sand,

vernal pool Vernal pools, also called vernal ponds or ephemeral pools, are seasonal pools of water that provide habitat for distinctive plants and animals. They are considered to be a distinctive type of wetland usually devoid of fish, and thus allow the saf ...

s, and ditches.

Description

The dwarf rush is a small annual herb not exceeding ten centimeters in height. The stems are erect and thready, flat or somewhat corrugated. The leaves are basal and up to 3 or 4 centimeters long. The plant is green to red or brownish in color. Each stem bears an

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 ...

of up to six clustered flowers. The pointed

bract In botany, a bract is a modified or specialized leaf, associated with a reproductive structure such as a flower, inflorescence axis or cone scale. Bracts are usually different from foliage leaves in size, color, shape or texture. They also lo ...

s at the base of the inflorescence are often over a centimeter long, longer the flower cluster itself, and are somewhat leaflike, giving the species its common name. Each flower has pointed outer

tepal A tepal is one of the outer parts of a flower (collectively the perianth). The term is used when these parts cannot easily be classified as either sepals or petals. This may be because the parts of the perianth are undifferentiated (i.e. of very ...

s and thinner, shorter, oval-shaped inner tepals. There are three

stamen The stamen (: stamina or stamens) is a part consisting of the male reproductive organs of a flower. Collectively, the stamens form the androecium., p. 10 Morphology and terminology A stamen typically consists of a stalk called the filament ...

s. The fruit is a tiny oval-shaped capsule one to two millimeters long.

Distribution and habitat

The dwarf rush is native to Europe, West Asia and North and East Africa. In the British Isles it is only known from Anglesey, Cornwall and the Channel Islands, and is rare in all these locations. It germinates in autumn and grows in places where water stands in winter and which dry up completely in summer, meaning the plant faces little competition. These locations include rock ledges on sea cliffs, around outcrops of

serpentine rock Serpentinite is a metamorphic rock composed predominantly of serpentine group minerals formed by serpentinization of mafic or ultramafic rocks. The ancient origin of the name is uncertain; it may be from the similarity of its texture or color ...

and in

dune A dune is a landform composed of wind- or water-driven sand. It typically takes the form of a mound, ridge, or hill. An area with dunes is called a dune system or a dune complex. A large dune complex is called a dune field, while broad, flat ...

slacks. In some locations it has sometimes been thought to be locally extinct, but then reappeared later.

References

External links

Jepson Manual TreatmentPhoto gallery
{{Taxonbar, from=Q161350 capitatus Flora of Europe Flora of Asia Flora of North Africa Plants described in 1772 Taxa named by Christian Ehrenfried Weigel