DWARF THISTLE

Cirsium acaule

Daisy & Dandelion Family [Asteraceae]

month8jun month8june month8jul month8july month8aug month8sep month8sept

Pappus: pappusZpossible (white, simple)
pappus8aug pappus8sep pappus8sept pappus8oct pappus8nov

status
statusZnative
 
flower
flower8purple
 
morph
morph8actino
 
petals
petalsZMany
 
stem
stem8round
 
stem
stem8spines stem8thorns
prickles
contact
contactZlowish
 

23rd July 2008, Mottistone Down, IoW. Photo: (CC by 2.0) Mike Cotterill
These are the thistles, which, without their flowerheads, look just like a nice flat patch of grass to sit on whilst you eat your butties. But automatic ejection is painful and abrupt!


23rd July 2008, Mottistone Down, IoW. Photo: (CC by 2.0) Mike Cotterill
They consist of a radial and warped (but flat and close against the ground) set of prickly green leaves - the basal rosette. The flower(s) appear in July to warn of their location, but otherwise, sit carefully!


23rd July 2008, Mottistone Down, IoW. Photo: (CC by 2.0) Mike Cotterill
The flowers usually appear either stalkless, or on very short stalks. Usually singly, but there can be 2 0r 3 together, as here.


13th July 2008, Alverston Down, IoW. Photo: (CC by 2.0) Geoff Toone
The inflorescence is magenta to purple and 12-25mm across.


13th July 2008, Alverston Down, IoW. Photo: (CC by 2.0) Geoff Toone
The flower stalks, if present, lack both prickles and leaves (as does the flowerhead and phyllaries). They can, on occasion, reach 10cm long, but always leafless. This specimen also has 3 flowers.


4th Aug 2008, Tennyson Down, IoW. Photo: (CC by 2.0) Mike Cotterill
The leaves are between 4 and 15cm long, dark-green and shiny with sharply-spined bracts which are often tipped reddish-purple (but not on these specimens).


Not to be semantically confused with : Dwarf Mouse-ear (Cerastium pumilum), Dwarf Cornel (Cornus suecica), Dwarf Spurge (Euphorbia exigua), Dwarf Cudweed (Gnaphalium supinum), Dwarf Mallow (Malva neglecta), Dwarf Milkwort (Polygala amarella), Dwarf Gorse (Ulex minor), Dwarf Marigold (Schkuhria pinnata) [other plants with similar names]

Hybridizes with :

  • Marsh Thistle (Cirsium palustre) to produce Cirsium × kirschlegeri
  • Meadow Thistle (Cirsium dissectum) to produce Cirsium × woodwardii
  • Spear Thistle (Cirsium vulgare) to produce Cirsium × sabaudum
  • Tuberous Thistle (Cirsium tuberosum) to produce Cirsium × medium
  • Creeping Thistle (Cirsium arvense) to produce Cirsium × boulayi
But none of these hybrids occur frequently, in fact they rarely occur at all anywhere.

Uniquely identifiable characteristics (but only when in flower)

Distinguishing Feature : Thistle flowers on no or ultra-short flower stalks.

Dwarf Thistle grows in short un-improved grassland on chalk or limestone. They occur in the White Peaks area, and in the South East of the UK. They is virtually no presence north of Filey on the East coast, nor any west of Taunton in Devon. Draw a line linking those two towns and most occurrences are SE of that line, with large areas missing. It is not rare, but your Author has never knowingly seen it in flower, although he may have attempted to sit on a basal rosette of it in his youth whilst walking the hills (but it could have been the basal rosette of some other thistle not yet in flower).


  Cirsium acaule  ⇐ Global Aspect ⇒ Asteraceae  

Distribution
 family8Daisy & Dandelion family8Asteraceae

 BSBI maps
genus8Cirsium
Cirsium
(Thistles)

DWARF THISTLE

Cirsium acaule

Daisy & Dandelion Family [Asteraceae]