Polygonum marinense
Encyclopedia
Polygonum marinense is a species of flowering plant in the knotweed family
known by the common name Marin knotweed. It is endemic to California
, where it is known from just a few locations around the northern San Francisco Bay Area
.
The taxonomy of the plant is uncertain; it is thought the species may exist in the Mediterranean
and California specimens may actually be introduced
. If, however, it is a true Bay Area endemic, the plant is rare and threatened by habitat destruction and disturbance. It is a resident of salt marsh
and other wet coastal habitat.
This is an annual herb producing a ribbed, reddish stem growing prostrate or erect to a maximum height near 40 centimeters. The narrow oval or lance-shaped leaves are alternately arranged along the slender stem. Each reddish leaf has a funnel-shaped stipule
that wraps around the leaf base to form an ochrea
. Flowers occur in the leaf axils. They are greenish with white or pink-tinged edges.
Polygonaceae
Polygonaceae is a family of flowering plants known informally as the "knotweed family" or "smartweed family"— "buckwheat family" in the United States. The name is based on the genus Polygonum and was first used by Antoine Laurent de Jussieu in 1789 in his book, Genera Plantarum. The name refers...
known by the common name Marin knotweed. It is endemic to California
California
California is a state located on the West Coast of the United States. It is by far the most populous U.S. state, and the third-largest by land area...
, where it is known from just a few locations around the northern San Francisco Bay Area
San Francisco Bay Area
The San Francisco Bay Area, commonly known as the Bay Area, is a populated region that surrounds the San Francisco and San Pablo estuaries in Northern California. The region encompasses metropolitan areas of San Francisco, Oakland, and San Jose, along with smaller urban and rural areas...
.
The taxonomy of the plant is uncertain; it is thought the species may exist in the Mediterranean
Mediterranean Basin
In biogeography, the Mediterranean Basin refers to the lands around the Mediterranean Sea that have a Mediterranean climate, with mild, rainy winters and hot, dry summers, which supports characteristic Mediterranean forests, woodlands, and scrub vegetation...
and California specimens may actually be introduced
Introduced species
An introduced species — or neozoon, alien, exotic, non-indigenous, or non-native species, or simply an introduction, is a species living outside its indigenous or native distributional range, and has arrived in an ecosystem or plant community by human activity, either deliberate or accidental...
. If, however, it is a true Bay Area endemic, the plant is rare and threatened by habitat destruction and disturbance. It is a resident of salt marsh
Salt marsh
A salt marsh is an environment in the upper coastal intertidal zone between land and salt water or brackish water, it is dominated by dense stands of halophytic plants such as herbs, grasses, or low shrubs. These plants are terrestrial in origin and are essential to the stability of the salt marsh...
and other wet coastal habitat.
This is an annual herb producing a ribbed, reddish stem growing prostrate or erect to a maximum height near 40 centimeters. The narrow oval or lance-shaped leaves are alternately arranged along the slender stem. Each reddish leaf has a funnel-shaped stipule
Stipule
In botany, stipule is a term coined by Linnaeus which refers to outgrowths borne on either side of the base of a leafstalk...
that wraps around the leaf base to form an ochrea
Ochrea
Ochrea, commonly spelled ocrea, is a structure formed of stipules fused into a sheath surrounding the stem. It is a diagnostic character in the Polygonaceae.In palms it denotes an extension of the leaf sheath beyond the petiole insertion....
. Flowers occur in the leaf axils. They are greenish with white or pink-tinged edges.