''Koenigia davisiae'' is a
flowering plant
Flowering plants are plants that bear flowers and fruits, and form the clade Angiospermae (), commonly called angiosperms. The term "angiosperm" is derived from the Greek words ('container, vessel') and ('seed'), and refers to those plants th ...
in the
knotweed family[ that is known by the common names Davis' knotweed or Newberry knotweed.
]
Distribution
''Koenigia davisiae'' is native to the western United States from Washington
Washington commonly refers to:
* Washington (state), United States
* Washington, D.C., the capital of the United States
** A metonym for the federal government of the United States
** Washington metropolitan area, the metropolitan area centered o ...
, Oregon
Oregon () is a U.S. state, state in the Pacific Northwest region of the Western United States. The Columbia River delineates much of Oregon's northern boundary with Washington (state), Washington, while the Snake River delineates much of it ...
, and central and northern California
California is a U.S. state, state in the Western United States, located along the West Coast of the United States, Pacific Coast. With nearly 39.2million residents across a total area of approximately , it is the List of states and territori ...
(northern Coast Ranges
The Pacific Coast Ranges (officially gazetted as the Pacific Mountain System in the United States) are the series of mountain ranges that stretch along the West Coast of North America from Alaska south to Northern and Central Mexico. Although th ...
and northern Sierra Nevada
The Sierra Nevada () is a mountain range in the Western United States, between the Central Valley of California and the Great Basin. The vast majority of the range lies in the state of California, although the Carson Range spur lies primarily ...
). There are also isolated populations in central Idaho
Idaho ( ) is a state in the Pacific Northwest region of the Western United States. To the north, it shares a small portion of the Canada–United States border with the province of British Columbia. It borders the states of Montana and Wyom ...
. It grows in high mountain habitat, such as talus and fellfield
A fellfield or fell field comprises the environment of a slope, usually alpine or tundra, where the dynamics of frost (freeze and thaw cycles) and of wind give rise to characteristic plant forms in scree interstices.
Soil dynamics
The freeze-thaw ...
s.Calflora taxon report, University of California, ''Aconogonon davisiae'' (W. H. Brewer ex A. Gray) Soják, Davis knotweed
/ref>
Description
''Koenigia davisiae'' is a perennial herb producing a decumbent or upright stem from a woody caudex
A caudex (plural: caudices) of a plant is a stem, but the term is also used to mean a rootstock and particularly a basal stem structure from which new growth arises.pages 456 and 695
In the strict sense of the term, meaning a stem, "caudex" is m ...
, growing to a maximum erect height near 40 centimeters (3 feet). Stems may be pale green to red in color. The leaves are oval and pointed or widely-lance-shaped to somewhat triangular, yellowish or pale green and waxy, slightly hairy, or smooth in texture. At the base of each leaf is a thin reddish sheath formed from the leaf's stipule
In botany, a stipule is an outgrowth typically borne on both sides (sometimes on just one side) of the base of a leafstalk (the petiole). Stipules are considered part of the anatomy of the leaf of a typical flowering plant, although in many speci ...
s which is known as the ochrea
An ochrea (Latin ''ocrea'', greave or protective legging), also spelled ocrea, is a plant structure formed of stipules fused into a sheath surrounding the stem, and is typically found in the Polygonaceae
The Polygonaceae are a family of flow ...
.[Flora of North America, ''Aconogonon davisiae'' (W. H. Brewer ex A. Gray) Soják, 1974. Davis's knotweed ]
/ref> In late summer to autumn, the leaves turn orange to red.[
]
References
External links
Jepson Manual Treatment - ''Polygonum davisiae''United States Department of Agriculture Plants Profile; ''Polygonum davisiae''''Polygonum davisiae'' - Calphotos Photo gallery, University of California
Polygonoideae
Flora of the Western United States
Plants described in 1872
Flora without expected TNC conservation status
{{Polygonaceae-stub