Galls and Rusts List |
Dock & Knotweed Family [Polygonaceae] |
status
flower
morph
petals
type
type
stem
sex
amphibious
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. |
30th June 2016, a small pond, freshfield, Sefton Coast. | Photo: © RWD |
The florets here the mostly old and bedraggled petals have fallen off revealing some anthers and a style or two. |
12th Aug 2005, Maghull, Leeds & Liverpool Canal. | Photo: © RWD |
Five pink rounded petals with protruding white stamens bearing pink anthers 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. |
30th June 2016, a small pond, freshfield, Sefton Coast. | Photo: © RWD |
This is a specimen which has probably only recently discovered that it is now standing in water - a very small pond. It's leaves are not floating on water, but are instead up in the air about something. Here are the minute forwardly-directed teeth on the leaf edge, possibly the tiniest leaf teeth your Author has never noticed before - the leaf stalk is off-screen to the right. |
TERRESTRIAL FORMMuch less frequent than the Amphibious form |
19th Aug 2017, Crosby Dunes, Sefton Coast | Photo: © RWD |
On sand dunes near the west coast. Sandy Shore is just over those hillocks where there's always something there to remind me :-) |
19th Aug 2017, Crosby Dunes, Sefton Coast | Photo: © RWD |
The sand lets any rain easily percolate through, keeping it relatively dry, certainly free of standing water. |
19th Aug 2017, Crosby Dunes, Sefton Coast | Photo: © RWD |
19th Aug 2017, Crosby Dunes, Sefton Coast | Photo: © RWD |
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 papery 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. |
A GALL |
Galls and Rusts Menu |
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. It occurs in water or wet places, riverbanks and as a weed on rough ground throughout of the British Isles.
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Persicaria | amphibia | ⇐ Global Aspect ⇒ | Polygonaceae |
Persicaria (Bistorts) |
Dock & Knotweed Family [Polygonaceae] |