something on violets

Year on year, the field season kicks off with the dilemma of telling the early from the common dog-violet. You know how it is…

The sweet violet, appearing first, lulls us into a false sense of security. Even if you don’t get one of the give-away colour variants, a quick turn of the flower heads reveals the blunt sepals and you go on your way confident that you understand the world. You can do it almost without slowing your pace. But in West Herefordshire the white one spatters the verges anyway, a giveaway of settlement. They are survivors. At Bredwardine church there are even a few clumps of wine-red colour.

Until 2013 I had spent most of the last 30 years in the north-east. Here, the problem of telling the early dog-violet Viola reichenbachiana from the common dog-violet Viola riviniana hardly arises, as the former is uncommon, giving up trying to make a living much north of Yorkshire. Back in southern Britain again, and I have to do my homework. I like the honesty of Clapham, Tutin & Moore (1987), who begin their account “scarcely distinguishable but…”

EARLY (reichenbachiana) note colour (violet!), and relatively narrow petals well-separated. Monmouthshire, April 2015. The petals are the worse for wear, having been out for perhaps a week or more.
EARLY (reichenbachiana) side view showing dark spur and small sepal appendages. Monmouthshire, 2015
COMMON (riviniana) note colour (blue-violet), relatively broad petals with more overlap; also pale spur and larger sepal appendages. Fresher plants, taken on the same date in Monmouthshire, 2015
Both species, COMMON above, EARLY below. Note petal colour and width differences as above, spur colouration, and sepal appendage size (differences most pronounced on the lower sepals). The photo also shows the tendency for riviniana spurs to be deep, and reichenbachiana ones to be more slender. Spur furrowing seems a bit unreliable to me though is obvious in good riviniana material; it can be seen in the preceding picture. Atlantic Spain, March 2008.
Both species, showing the difficulties of measuring sepal appendages! Spain, March 2008.
Both species, COMMON right, EARLY left. Differences in petal width and separation harder to discern in these examples, but colour differences maintained. Atlantic Spain, March 2008.

Both species, COMMON above and EARLY below. Sepal appendage size increases in fruit greatly in the former and almost not at all in the latter, but these photos are not of mature fruit. Atlantic Spain, March 2008.

Riviniana is a plant of woodland or grassland, but reichenbachiana is seldom seen outside of woodlands, I think. Please will botanists local to Herefordshire, the Marches, (or indeed anywhere!), leave comments below on their understanding of the ecology of these two species.

Sweet-violets aside, in terms of practical help the first violet vigilant botanists in the South will see in the woods is Viola reichenbachiana (the first violet vigilant botanists in north of the Tees will see in their woods is probably going to be Viola riviniana). Herefordshire botanists should clock these early plants, and park them in their consciousness in preparation for the arrival of the other species a fortnight later. As always, accept that a positive identification may not always be possible. Get up, move on, and look for more typical material. The chances are you will see some before your walk is over.

It is indeed awful to have to type or say reichenbachiana so frequently at this time of year. We should console ourselves the early dog-violet remembers Ludwig Reichenbach (1793 – 1879), he of the famous glass flowers which must have done a lot to win people over to field botany.

By the way, Viola canina, what might legitimately claim to be the true dog-violet, is in dire straits in Herefordshire, as in most of Britain. So much so it need not concern us as a source of confusion. But that is for another post.

  1. Fiona Everingham

    Brilliant, I don’t know where you find the time and energy to put this together! I am inspired now to go out and look more closely at all the violets that are springing up….which will probably all prove to be V.riviniana. Thanks

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