COMMON DOG-VIOLET

Viola riviniana

Violet Family [Violaceae]

month8mar month8march month8apr month8april month8may month8jul month8july month8aug month8sept month8oct

status
statusZnative
flower
flower8mauve
flower
flower8indigo
inner
inner8cream
morph
morph8zygo
petals
petalsZ5
type
typeZspurred
stem
stem8square

13th April 2016, Old Clough Lane, Walkden, M/cr. Photo: © RWD
The commonest Violet, growing to 20cm from sea level to mountains 1000m high.


13th April 2016, Old Clough Lane, Walkden, M/cr. Photo: © RWD
Leaves heart shaped and as wide as they are long.


14th May 2010, Lumley Fee, Helsington Barrows, Lancs. Photo: © RWD
With spur that is always paler than the flowers, usually cream to white and with a definite notch at the end.


13th April 2016, Old Clough Lane, Walkden, M/cr. Photo: © RWD
Leaves with rounded (crenate) teeth.


13th April 2016, Old Clough Lane, Walkden, M/cr. Photo: © RWD
Petals usually overlapping.


14th April 2015, Yarrow Valley Park, Chorley, Lancs. Photo: © RWD
Flowers 14mm - 25mm across and bluish-mauve with a white throat.


13th April 2016, Old Clough Lane, Walkden, M/cr. Photo: © RWD
The branched dark markings on the central lowest petal are longer than those of the similar Early Dog-violet (Viola reichenbachiana).


13th April 2016, Old Clough Lane, Walkden, M/cr. Photo: © RWD
Unlike either Early Dog-violet (Viola reichenbachiana) or Sweet Violet (Viola odorata) the sepals are pointed. Sepals also have a flap-appendage at the rear that longer than 1.5mm. Spur is stout and baggy


13th April 2016, Old Clough Lane, Walkden, M/cr. Photo: © RWD
There are 5 sepals in all (the same for all Violets), two by the side and three nearer the top.


1st May 2013, Grindleford, Derbyshire. Photo: © RWD
A distinctive feature of Common Dog-violet is the distinct notch in the spur at the rear.


1st May 2013, Grindleford, Derbyshire. Photo: © RWD
Distinctive notch in spur.


1st May 2013, Grindleford, Derbyshire. Photo: © RWD
Sepal appendages visible here. Spur is stout and baggy


14th May 2010, Lumley Fee, Helsington Barrows, Lancs. Photo: © RWD
The stem of the flower also has leaves. But the basal rosette of leaves is set away from the flower and is without a flower stalk.


13th April 2016, Old Clough Lane, Walkden, M/cr. Photo: © RWD
Leaves un-rolling.


Not to be semantically confused with : Dog Rose (Rosa canina) nor with Dog's Mercury (Mercurianis perennis), nor with Dame's-Violet (Hesperis matronalis), a Cabbage Family plant nor with Water Violet (Hottonia palustris) nor Dog's-Tooth-Violet (Erythronium dens-canis) a member of the Lily Family.

Easily mistaken for : other Violets and Dog-violets (see captions for differentiation)

Hybridizes with :

  • Teesdale Violet (Viola rupestris) to produce Viola × burnatti which is found with the parents in Upper Teesdale, County Durham and is intermediate in most characteristics. It is sterile.
  • Early Dog-violet (Viola reichenbachiana) to produce Viola × bavarica which has sepal appendages (to be found at the rear of the sepal) which are intermediate in length. It occurs only rarely where both parents are found. Nearly all are sterile.
  • Heath Dog-violet (Viola canina) to produce Viola × intersita is intermediate in leaf characteristics and habit. Found scattered on heaths and dunes where the parents cohabit. It is sterile.
  • Pale Dog-violet (Viola lactea) to produce Viola × lambertii occurs frequently where Pale Dog-violet occurs and is intermediate in leaf and flower characteristics and in habit. Nearly all are sterile.
Your Author does not know if any of the above photos might be of any hybrids.

Some similarities to : several Pansies to which they are closely related but they are usually much taller and bushier except for Mountain Pansy (Viola lutea).

A feature of Common Dog-violet is that the basal rosette of leaves lacks a flower stalk, which is somewhere else nearby and has its own leaves on the flower-stalk. It is a native perennial growing in from sea level to 1075m high in the UK. It is common in woodland preferring a half-shady place, but is also found in hedgebanks, grassland, heathland, moorland and even on shingle amidst other plants and grasses, on rocks and cliff edges. Grows on all but the most acidic soils (such as peat-bogs). The notch in the very pale spur is also an identifying feature (but that may be present in the hybrids above also). It is only sparsely hairy if at all.

It can sometimes flower twice in a season, the second time, around July to October but usually lacking petals or failing to open, pollinating itself in the bud.


CLEISTOGAMY

Cleistogamous flowers are flowers which are able to pollinate themselves by using flowers which do not open. This behaviour is well known in Peas and Beans (Fabaceae) but the largest genus of cleistogamic plants are Viola. Only a few specimens of Viola are actually cleistogamic. These flowers are usually much smaller than normal flowers and they do not open; this saves using up valuable resources in making a flower large enough to attract external pollinating insects. Cleistogamy is normally a retrograde step for flowers since, by self-pollination, they are not using the ability of normal cross-pollination to increase the gene pool for better resilience against changing conditions or new infectious agents. But it serves a useful purpose in being able to survive in harsh conditions. Changes to the genes, do, however, occur even during cleistogamic fertilisation, but certainly not as many as by normal pollination by other like plants. Some plants, such as Orange Balsam (Impatiens capensis), can become cleistogamic after being severely damaged, and this allows them to at least propagate themselves.
Some plant species are always cleistogamous and never seem to open their flowers, therefore cannot indulge in sexual reproduction - one such being a new species of orchid discovered in 2016 (namely Gastrodia kuroshimensis, which is in the tribe Epidendroideae) and was found on the tiny Japanese island of Kuroshima. This orchid also lacks chlorophyll; it's flowers are brown and its stem a pale fawn-brown and therefore cannot photosynthesize and are myco-heterotrophic (on underground fungi). [It is also true that most orchids, even ones which do possess chlorophyll (i.e. have green parts) and can photosynthesize are also dependant upon a symbiotic relationship with underground fungi for at least some of their nutrition - but they do share other stuff with the fungi]

  Self-pollination

  Cleistogamy


USE BY BUTTERFLIES
LAYS EGGS ON CATERPILLAR CHRYSALIS BUTTERFLY
Pearl-bordered Frittilary
Small Pearl-bordered Frittilary
Dark Green Frittilary
High Brown Frittilary
Frittilary
Silver-washed Frittilary



  Viola riviniana  ⇐ Global Aspect ⇒ Violaceae  

Distribution
 family8Violet family8Violaceae
 BSBI maps
genus8Viola
Viola
(Violas)

COMMON DOG-VIOLET

Viola riviniana

Violet Family [Violaceae]