Dock & Knotweed Family [Polygonaceae] |
status
flower
inner
morph
petals
stem
stem
rarity
(ssp. raii)
23rd July 2016, Ainsdale dunes, Sefton Coast. | Photo: © RWD |
Bird's-eye view, about a foot across. |
23rd July 2016, Ainsdale dunes, Sefton Coast. | Photo: © RWD |
Small flowers in most leaf-axils. |
24th July 2011, Booley Bay, Eire. | Photo: © Paula O'Meara |
Straggles up to a metre in length (often much shorter) on coastal sand and shingle. |
24th July 2011, Booley Bay, Eire. | Photo: © Paula O'Meara |
Stems thicker and more robust than other Knotgrasses except for the much rarer Sea Knotgrasswhich also shares the same larger flowers and prominent fruit of Ray's Knotgrass. |
24th July 2011, Booley Bay, Eire. | Photo: © Paula O'Meara |
Un-like Sea Knotgrassleaves not in-curled at the margins. |
24th July 2011, Booley Bay, Eire. | Photo: © Paula O'Meara |
Flowers larger than other Knotgrasses except Sea Knotgrass. Between 2-6 flowers nestle in axis of each leaf. Leaves single on alternate sides of stems. |
24th July 2011, Booley Bay, Eire. | Photo: © Paula O'Meara |
Flowers have five white 'petals' (actually tepals), sometimes pink-edged. Stems multi-angular or multi-ridged. The pink/white papery sheaths at each node are short. Fruits chestnut-brown and glossy, protruding from dead flowers. |
23rd July 2016, Ainsdale dunes, Sefton Coast. | Photo: © RWD |
Papery sheaths at each node on the stem. |
18th July 2017, Hightown coast, Sefton Coast. | Photo: © RWD |
Side view of just one flower. The lime-green tepals become pink or white towards the opening. The fibrous rice-paper-thin sheath at the junctions here has a reticulalated lizard-skin pattern. |
24th July 2011, Booley Bay, Eire. | Photo: © Paula O'Meara |
Leaves (and stems) have a fine grainy appearance typical of plants which are frequently exposed to sea salt-water; they have to have a mechanism for getting rid of the salt which they inevitably uptake when absorbing the moisture in the sand. |
18th July 2017, Hightown coast, Sefton Coast. | Photo: © RWD |
One still in flower, the other two gone to fruit. |
24th July 2011, Booley Bay, Eire. | Photo: © Paula O'Meara |
Flowers can be pink when in bud (leftmost). |
23rd July 2016, Ainsdale dunes, Sefton Coast. | Photo: © RWD |
The flowers emerge from a pale-brown blending to white sheath at a leaf-node. |
23rd July 2016, Ainsdale dunes, Sefton Coast. | Photo: © RWD |
Each flower has 5 tepals (they are not called petals because there are no sepals). The tepals are green with a wide white margin. The fruit is an achene, which is brown, shiny, tapers to a point with the remains of 3 short now brown stigmas atop. The fruit is widest near the base and has 3 noticeably indented sides. |
23rd July 2016, Ainsdale dunes, Sefton Coast. | Photo: © RWD |
Within the corolla are 8 stamens with yellow anthers and three small, almost sessile stigma, which are also yellow. |
18th July 2017, Hightown coast, Sefton Coast. | Photo: © RWD |
Flowers have 8 stamens with yellow anthers and 3 white discoidally-terminated styles. |
23rd July 2016, Ainsdale dunes, Sefton Coast. | Photo: © RWD |
One of the 3 discoidal stigmas can be seen here, as well as several x-shaped anthers which are a deeper-yellow in colour. |
18th July 2017, Hightown coast, Sefton Coast. | Photo: © RWD |
The fruits have 3 concave sides tapering to the remains of 3 styles which are still attached; albeit now brown. Plants which grown beside the sea typically have a white frosty appearance with tiny pimples over them, here plainly visible on the fruit. |
Not to be semantically confused with : The Genus name of Knotgrasses, Polygonum can easily be misinterpreted as Polygonatum which is the genus name of Solomon's-seals such as Angular Solomon's-Seal (Polygonatum odoratum).
No relation to : Knotted Clover,
Easily mis-identified as : Some similarities to : Knotgrass but that is less compact and with less stout stems.
Slight resemblance to : A rare plant! Rays's Knotgrass is procumbent and usually an annual (only sometimes perennial). It is branched and can grow to 1m in length, and is sometimes woody nearer the roots. It is native and grows near the sea on sandy beaches, sometimes close enough to get washed away by forceful spring tides. It is found as one of two species:
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Polygonum | oxyspermum | ⇐ Global Aspect ⇒ | Polygonaceae |
Polygonum (Knotgrasses) |
Dock & Knotweed Family [Polygonaceae] |