Polygonum douglasii
Encyclopedia
Polygonum douglasii is a species of flowering plant in the knotweed family
known by the common name Douglas's knotweed. It is native to much of northern and western North America, where it can be found in many types of habitat, including disturbed areas.
This plant species is known as a species complex
, as there are many subspecies that may be better treated as species in their own right.
The plant is variable in morphology
and the subspecies are often difficult to distinguish. In general, plants in this complex are annual herbs growing erect to maximum heights anywhere between 3 and 80 centimeters with thin, angular stems. High-elevation plants are smaller and may be decumbent in form. The leaves are linear or widely lance-shaped, sometimes falling away to leave the plant mostly naked in flowering, or reduced to tiny scales at the stem tips. The flowers are a few millimeters long, pink to white in color, sometimes remaining closed or opening together in a clusterlike inflorescence
.
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 Douglas's knotweed. It is native to much of northern and western North America, where it can be found in many types of habitat, including disturbed areas.
This plant species is known as a species complex
Cryptic species complex
In biology, a cryptic species complex is a group of species which satisfy the biological definition of species—that is, they are reproductively isolated from each other—but whose morphology is very similar ....
, as there are many subspecies that may be better treated as species in their own right.
The plant is variable in morphology
Morphology (biology)
In biology, morphology is a branch of bioscience dealing with the study of the form and structure of organisms and their specific structural features....
and the subspecies are often difficult to distinguish. In general, plants in this complex are annual herbs growing erect to maximum heights anywhere between 3 and 80 centimeters with thin, angular stems. High-elevation plants are smaller and may be decumbent in form. The leaves are linear or widely lance-shaped, sometimes falling away to leave the plant mostly naked in flowering, or reduced to tiny scales at the stem tips. The flowers are a few millimeters long, pink to white in color, sometimes remaining closed or opening together in a clusterlike inflorescence
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. Strictly, it is the part of the shoot of seed plants where flowers are formed and which is accordingly modified...
.