- Polygonum ramosissimum
Taxobox
name = "Bushy knotweed"
image_width = 240px
image_caption =
regnum =Plant ae
divisio = Magnoliophyta
classis = Magnoliopsida
ordo =Caryophyllales
familia =Polygonaceae
genus =Polygonum
species = "P. ramosissimum"
binomial = "Polygonum ramosissimum"
binomial_authority =Michx "Polygonum ramosissimum" is a herbaceous annual plant species" [http://plants.usda.gov/java/profile?symbol=PORAR Polygonum ramosissimum] " from the
USDA , retrieved 07/14/2008] native from most of North America, were it is commonly called Bushy knotweed.Description
Plants have erect stems growing 30 to 100cm (sometimes to 200cm) tall, with yellowish-green to blue-green colored foliage. The stems are freely branched with closed flowers produced in groups of (1) 2 to 3(5) flowers in the upper ocreae of racemes that are up to 15 cm long, the inflorescences are spike like. The greenish-yellow, rarely pink or white marked flowers, are on pedicels that are longer than the calyx. The calyx is around 3 mm long and 5-parted with the outer three sepals longer than the inner sepals. The seeds are produced in fruits called achenes, which are ovoid in shape, dark brown in color and around 3 mm long. The achenes also have a smooth shiny surface. The late season achenes are larger, from 4 to 15mm long. [cite book| last = Gleason, A.| first = Henry| title = The new Britton and Brown illustrated flora of the northeastern United States and adjacent Canada.| publisher = New York Botanical Garden by Hafner Pub. Co.| date = 1963| pages = pp 72-84| isbn = 63-16478] [http://www.efloras.org/florataxon.aspx?flora_id=1&taxon_id=242417034 Polygonum ramosissimum in Flora of North America @ efloras.org ] ]
There are a number of forms and two subspecies, that vary in flower and foliage coloration. "Polygonum ramosissimum" has great morphological variability, which is notable on the same plant, between flowers and fruits produced early in the blooming season verses those produced late in the season, plants also show great variation over geographical areas.
In Maryland it is listed as endangered or extirpated from the state, in Pennsylvania it has been exterminated from the state, and New Hampshire lists it as threatened.
References
Wikimedia Foundation. 2010.
