Viola reichenbachiana Jord. ex Boreau, Early Dog-violet

Account Summary

Growth form and preferred habitats

This perennial dog-violet flowers early in the year – in late February, about a fortnight before the other, much more common violet, V. riviniana (Common Dog-violet). Like the latter, some V. reichenbachiana plants produce a second flush of entirely self-pollinated (ie cleistogamous) flowers late in the summer. The flowers are usually pale violet and have very narrow upper petals that do not overlap and are sharply bent backwards (reflexed). The lowest petal is marked with unbranched or little-branched dark veins and the attached deep purple, or deep lilac spur is slender and darker in colour than the rest of the flower. These are the most distinctive identification features of the species when in flower. When not in flower, the plant can be recognised by its narrow leaf stipules, which have marginal fimbriae considerably longer than those of V. riviniana (Porter & Foley 2017).

V. reichenbachiana is a plant of lowland deciduous woodlands, hedgerows and wood edges. It is also much more lime-tolerant than V. riviniana. Like the latter, it normally competes best under shade conditions. However, Early Dog-violet also occurs more rarely in open, well-lit situations in limestone grasslands and even on calcareous screes, provided there are other environmental factors that limit the vigour of its ecological rivals, eg a shallow, free-draining substrate, or low or unbalanced soil nutrient levels.

Variation

In the past, V. reichenbachiana was combined with V. riviniana in V. silvatica Fr., but cytological studies have shown that in fact V. reichenbachiana is a diploid with 2n=20 chromosomes, whereas V. riviniana has various chromosome numbers, ie 2n=35, 40, 45, 46, 47 (but most often 2n=40). Plants of V. riviniana with more than 40 chromosomes in their nuclei are aneuploid forms which have five, six or seven small supernumerary or B-chromosomes present (Gadella 1963).

Sell & Murrell (2018) mention an occasional form of the species with purple blotches on the lower petal, named var. punctata (Rouy & Foucaud) P.D. Sell, and Porter & Foley (2017) detail a rare, almost pure white flowered form, sometimes called var. leucantha Beck.

Flowering reproduction

Flowers are without scent and seed production from the spring anthesis is low. The closed flowers, that are sometimes produced later in the year, self-pollinate in bud (ie they are cleistogamous) and they produce more seed than the open pollinated ones (Sell & Murrell 2019).

Seed dispersal

The seed of V. reichenbachiana bears a small elaiosome food appendage and therefore presumably it is secondarily dispersed by ants to some extent. (For more detail of this mechanism, see the species accounts of V. riviniana and V. odorata (Sweet Violet)).

Fermanagh occurrence

Our experience of Early Dog-violet in Fermanagh suggests that it is much commoner than most authorities would have us believe. V. reichenbachiana has been frequently recorded in 130 Fermanagh tetrads, 24.6% of those in the VC. We reckon that despite our efforts it remains under-recorded due to its early flowering and probably it is even more widespread in lowland Fermanagh and especially so on limestone soils.

The current survey shows it is a very characteristic plant of hazel woods in springtime, where it flowers from March to May, with a notable peak in April. However, it is identifiable and is recorded in much smaller numbers right through the summer months, even into October. Typical habitats are in deciduous woods and shady hedgebanks along roads, rivers and by lakeshores.

British and Irish occurrence

V. reichenbachiana is common in suitable habitats across much of both England and Ireland although it thins markedly northwards and is rare in Scotland and absent from most of W Wales and SW England (New Atlas; Porter & Foley 2017).

European occurrence

V. reichenbachiana is restricted to Europe and adjacent parts of Africa (including the Canary Isles) and W Asia (Hultén & Fries 1986, Map 1324). It is widespread but uncommon in suitable habitats in W & C Europe from S Sweden southwards to Greece and eastwards from Spain to the Caucasus (Sell & Murrell 2018).

Name

The specific epithet is the Latinised name of the Dresden botanist and taxonomist, H.G. Ludwig Reichenbach (1793-1879), in whose honour the plant is named.

Threats

None.

• Find out more about the format of the species accounts
• View abbreviations
• View references for all species accounts
• View a gazetteer of all the sites