Galls and Rusts List 

AMPHIBIOUS BISTORT

Persicaria amphibia

Dock & Knotweed Family [Polygonaceae]  

month8jul month8july month8Aug month8sep month8sept

status
statusZnative
flower
flower8pink
morph
morph8actino
petals
petalsZ5
type
typeZclustered
stem
stem8round

AMPHIBIOUS FORM

12th Aug 2005, Maghull, Leeds & Liverpool Canal. Photo: © RWD
The amphibious form has floating leaves that differ from the terrestrial form in being heart-shaped near the base.


14th July 2007, Bridgewater Canal, Salford, Greater Manchester. Photo: © RWD
The flowers are held about 2 - 4 inches above the level of the water.


12th Aug 2005, Maghull, Leeds & Liverpool Canal. Photo: © RWD
Five pink rounded petals with protruding white stamens bearing pink anters on them.


22nd June 2007, Waters Meet, Bridgewater Canal, Eccles, Greater Manchester Photo: © RWD
Unlike the terrestrial form the leaves are hairless and have a slightly heart-shaped base.


TERRESTRIAL FORM

Much less frequent than the Amphibious form
20th Aug 2014, waste ground, Hightown, Sefton Coast Photo: © RWD
On land it grows up to 60cm tall. It totally lacks the dark chevrons on the leaves typical of Redleg.


20th Aug 2014, waste ground, Hightown, Sefton Coast Photo: © RWD
Bird's-eye view. The terrestrial form differs from the amphibious form in that the leaves are smaller and they are oblong-lanceolate and not oblong heart-shaped with rounded auricles at the base and are slightly hairy. The terrestrial form is also often barren without flowers.


20th Aug 2014, waste ground, Hightown, Sefton Coast Photo: © RWD
The flowers are much the same as those of the amphibious form.


20th Aug 2014, waste ground, Hightown, Sefton Coast Photo: © RWD
As-yet unopened flowers at the bottom, some open ones in the middle with slightly protruding white stamens bearing pink anthers.


20th Aug 2014, waste ground, Hightown, Sefton Coast Photo: © RWD
Each floret has a brown paperish sheath around the base.


20th Aug 2014, waste ground, Hightown, Sefton Coast Photo: © RWD
Unlike the otherwise fairly similar Redshank (those lacking the not-always-present dark chevron on the leaves), the sheaths are not frilly.


20th Aug 2014, waste ground, Hightown, Sefton Coast Photo: © RWD
Un-like the amphibious form the leaves may be slightly hairy.


WACHTLIELLA PERSICARIA GALL
on the Terrestrial Form

9th Aug 2014, waste ground, Hightown, Sefton Coast. Photo: © RWD
A gall formed on Bistort leaves (this specimen infecting the top three leaves on the Terrestrial form of Amphibious Bistort, but it can infest Common Bistort) by the gall mite Wachtliella Persicariae which causes a severe distortion of the leaves. It can cause just the rolling up and thickening of leaf margins or the whole leaf to roll up completely and redden. If there is one plant infected, the likelihood is that several others nearby will be similarly affected, as was the case here.


5th July 2014, Rimrose Valley Country Pk, Sefton. Photo: © RWD
Unlike other leaf galls that cause the rolling up of leaf margins, this gall makes the leaves so brittle that they cannot be un-rolled without breaking them. It is found throughout summer with each gall containing several light-red or orange larvae which pupate later in the year.


The same plant can exist in two slightly different forms, the amphibious form either on wet grass near water, or actually in the water; or the terrestrial form which is well away from water on waste ground.


  Persicaria amphibia  ⇐ Global Aspect ⇒ Polygonaceae  

Distribution
family8dock family8knotweed family8Polygonaceae

 BSBI maps
genus8persicaria
Persicaria
(Bistorts)

AMPHIBIOUS BISTORT

Persicaria amphibia

Dock & Knotweed Family [Polygonaceae]  

WildFlowerFinder Homepage