SEA ASTER

Aster tripolium

(aka: Tripolium pannonicum and Aster pannonicum )
Daisy & Dandelion Family [Asteraceae]

month8jul month8july month8aug month8sep month8sept month8oct

status
statusZnative
flower
flower8azure
flower
flower8white
inner
inner8yellow
morph
morph8actino
petals
petalsZMany
stem
stem8round
stem
stem8ribbed

Aster tripolium var. flosculosus

(aka var. discoideus) Disc florets only - no ray florets (flowers yellow only)
[sorry - no photos yet]

Aster tripolium var. tripolium

Has ray florets (which are azure through to white) and yellow disc florets

1st Aug 2013, shoreline, Hightown, Sefton Coast Photo: © RWD
In the tidal zone with other salt-marsh loving species such as the salt-marsh sub-species of Curled Dock (Rumex crispus ssp. littoreus) which is just behind it (and in the left-hand bottom corner).


1st Aug 2013, shoreline, Hightown, Sefton Coast Photo: © RWD
The plant is semi-succulent with thickish leaves and stems. A biennial (sometimes annual) growing up to 1m high by the sea or on tidal rivers but usually and most prolifically on saltmarshes.


1st Aug 2013, shoreline, Hightown, Sefton Coast Photo: © RWD
Although on sand, this is still well within the tidal zone (farther up the beach is Prickly Saltwort with which it may share some similarities when not in flower - but that has sharp spines whereas Sea Aster has none).


1st Aug 2013, shoreline, Hightown, Sefton Coast Photo: © RWD
Has a strange admixture of narrow, thick lanceolate leaves and wider lanceolate leaves, a little strap-shaped. This specimen in bud, few have yet opened.


1st Aug 2013, shoreline, Hightown, Sefton Coast Photo: © RWD
Probably the only species of the Dandelion & Daisy family (Asteraceae) which likes brackish water and sea water. Leaves are fleshy and slightly glaucous-green.


1st Aug 2013, shoreline, Hightown, Sefton Coast Photo: © RWD
Two varieties exist, the rayed variety (as here) is the most abundant whereas the un-rayed variety with yellow disc florets looking a little like a salt-tolerant Groundsell only occurs in a few select places on the coast of Britain.


5th Aug 2009, saltmarshes, Lytham st. Annes, Fylde Coast. Photo: © RWD
The azure ray florets (sometimes paler to even white) are 12-20mm long. The yellow disc florets are flamboyant.


5th Aug 2009, saltmarshes, Lytham st. Annes, Fylde Coast. Photo: © RWD
Disc florets fading away.


5th Aug 2009, saltmarshes, Lytham st. Annes, Fylde Coast. Photo: © RWD
Disc florets turning to seed.


1st Aug 2013, shoreline, Hightown, Sefton Coast Photo: © RWD
Un-opened flower buds may at first resemble the rayless variety. Leaves have a central vein, translucent by transmitted light.


5th Aug 2009, saltmarshes, Lytham st. Annes, Fylde Coast. Photo: © RWD
Stem leaves un-stalked and thickish and 7 to 12cm long.


5th Aug 2009, saltmarshes, Lytham st. Annes, Fylde Coast. Photo: © RWD
Phyllaries of unequal length and much blunter than all other Aster species.


5th Aug 2009, saltmarshes, Lytham st. Annes, Fylde Coast. Photo: © RWD


1st Aug 2013, shoreline, Hightown, Sefton Coast Photo: © RWD
Leaves with very short whitish hairs?


10th Oct 2015, saltmarshes, Marshside, Southport, Sefton Coast. Photo: © RWD
In october the seed heads with pappii appear en-masse.


10th Oct 2015, saltmarshes, Marshside, Southport, Sefton Coast. Photo: © RWD
Pappii off-white.


10th Oct 2015, saltmarshes, Marshside, Southport, Sefton Coast. Photo: © RWD
Seeds long, striated and shuttle-cock shaped. Pappus with simple hairs.


5th Aug 2009, saltmarshes, Lytham st. Annes, Fylde Coast. Photo: © RWD
Basal leaves shoe-horn shaped.


Not to be semantically confused with : Cotoneaster (Cotoneaster) [plants with similar name]

Easily mistaken for : Saltmarsh Aster (Aster squamatus) which is an introduced non-native plant which is likely to spread, but at the moment is only known near South Hants, South Devon & County Dublin. Unlike Sea Aster it has phyllaries with broad scarious margin along its whole length.

Easily mis-identified as : Flower ()

Some similarities to : many species of Michaelmas Daisy but they grow inland away from salt spray or salty water and they do not have semi-succullent leaves or stems.

Uniquely identifiable characteristics

Distinguishing Feature :

Sea Aster grows up to 1m high near the sea, most often in saltmarshes, but also beside tidal rivers but rarely on inland salty areas. It occurs less often on coastal cliffs and rocks. Two (or three) varieties occur, with var. tripolium being the most extensive. The other two varieties only occur in just very few seaside locations.

For some strange reason Clive Stace's book makes no mention of any varieties; Harraps' book mentions only var. triplium and var. flosculosus, whereas BSBI maps mentions three varieties: var. trifolius, var. arctiumm, var. discoideus and var. tripolium (omitting any mention of var. flosculosus! Your Author is puzzled, but thinks that var. flosculosus might be synonymous with var. discoideus (which seems logical given that variety lacks ray-florets possessing only disc-florets - but that still leaves var. arctium)


  Aster tripolium  ⇐ Global Aspect ⇒ Asteraceae  

Distribution
 family8Daisy & Dandelion family8Asteraceae

 BSBI maps

BSBI Distribution Maps
 family8Daisy & Dandelion family8Asteraceae
 tripolium??
 family8Daisy & Dandelion family8Asteraceae
 sens. lat.
 family8Daisy & Dandelion family8Asteraceae
 flosculosus??

genus8Aster
Aster
(Michaelmas-Daisies)

SEA ASTER

Aster tripolium

(aka: Tripolium pannonicum and Aster pannonicum )
Daisy & Dandelion Family [Asteraceae]