Jointleaf rush

Description

Juncus articulatus is a flowering plant species in the rush family Juncaceae. It is known by the common name jointleaf rush or jointed rush, which can also refer to J. kraussii from Australia. It is native to Eurasia, Canada, Greenland, and much of the United States.It grows in moist areas, such as wet sand, and thrives in calcareous soils. J. articulatus was found to be more sensitive to drought and salt stress than its congeners J. acutus and J. maritimus. It is a perennial herb producing mainly erect stems from a short rhizome. The stem may root at nodes, and it generally has one or more flattened hollow cylindrical leaves up to 10 centimeters long. Transverse internal partitions or joints may be seen or felt in the leaf of the plant. The inflorescence atop the stem has several branches with up to 25 clusters of up to 12 flowers each. Each individual flower has greenish to dark brown, pointed tepals 2 to 3 millimeters long, six stamens bearing anthers, and a protruding, feathery pistil. The fruit is a dark brown capsule with a pointed tip. Juncus is a genus of monocotyledonous flowering plants, commonly known as rushes. It is the largest genus in the family Juncaceae, containing around 300 species. Rushes of the genus Juncus are herbaceous plants that superficially resemble grasses or sedges. They have historically received little attention from botanists; in his 1819 monograph, James Ebenezer Bicheno described the genus as "obscure and uninviting". The form of the flower differentiates rushes from grasses or sedges. The flowers of Juncus comprise five whorls of floral parts: three sepals, three petals (or, taken together, six tepals), two to six stamens (in two whorls) and a stigma with three lobes. The stems are round in cross-section, unlike those of sedges, which are typically somewhat triangular in cross-section. In Juncus section Juncotypus (formerly called Juncus subg. Genuini), which contains some of the most widespread and familiar species, the leaves are reduced to sheaths around the base of the stem and the bract subtending the inflorescence closely resembles a continuation of the stem, giving the appearance that the inflorescence is lateral. Juncus has a cosmopolitan distribution, with species found throughout the world, with the exception of Antarctica. They typically grow in cold or wet habitats, and in the tropics, are most common in montane environments.