Sweet Violet, Viola odorata, and Common Dog-Violet, Viola riviniana.
New Years resolution part two...
Winter is a great time to work on the bare stems of woody plants and our gorgeous winter flowers, for example the native Stinking Hellebore (Hellborus foetidus) and the spectacular seed heads of the native Stinking Iris (Iris foetidissima). However, spring is fast approaching. In Cambridge the snowdrops have just started to flower and the daffodils are showing rapid growth, so if you live in the northern hemisphere it’s time to start planning for your spring painting list to keep your resolutions fresh.
Following Martin Allen's first resolution Sheelagh Keane provides some background about a well loved plant to add to your painting list. This tiny, sweetly scented spring flower which would make a good subject.
The ABBA Team
Violets - Genus Viola
Violets are tiny floral champions of the countryside which play an important role in the ecology of hedgerows, verges, woodlands, marshes, rocky ground and gardens. As part of their role they act as a food source for some species of wildlife, being a source of nectar, or act as a foodplant for the larval stages of some species of butterfly.
Viola sp is a genus of the family Violacae. There are ten species, in the United Kingdom and thousands worldwide. This genus includes the commonly seen pansies.
Violets are intimately entwined with humans, in our culture, literature, medicine and commercial activities. They contain chemical components which are of both medicinal and industrial value. In addition they are also highly praised for their aesthetic appeal and it would be sad to see them overlooked in favour of more striking native flowers or those at risk of immediate extinction.
Sweet Violet, Viola odorata, and Common Dog-Violet, Viola riviniana.
In literature the growth habit gave rise to centuries of poetry and cultural admiration - Shakespeare mentioned ‘nodding violets’ in a Midsummer Night's Dream, we use the term ‘shrinking violet’. The latter reflects the appearance of the flower head to be shyly tucked downwards. Sweet Violet or Viola odorata also gives off a highly characteristic scent much favoured by humans whilst V. riviniana has a scent attractive to fritillary butterflies but alas, is not perceived by humans.
Although not flowering at the time of writing (September 2019) they can occasionally give rise to tiny non-opening flowers which are self-fertilising, cleistogamous (meaning closed marriage). Thus enabling seed formation at a time when fewer insects are available to aid pollination. At this time of year V. odorata can be identified by the dark green oval leaves, which will have have grown larger since flowering time ended in early summer.
The violet packs a botanical punch far above the tiny proportions of the flowers. The intricate plant structures of the species are highly specialised and subtly differentiated in minute ways. This is what makes it a botanical artists delight -the differences between the species are tiny and beautiful. The little style for instance is curved but not extended in the Viola odorata , (see my sketchbook drawings)
and straight in the V. riviniana. Also, in V.odorata the flower arises from the plant root, whilst that of the V. riviniana originates from a leaf rosette. The flowers in each species hang delicately over the stem, as the flower stem is curved.
I undertook to draw some last year - as a lay person, not a botanist - and was bowled over by their intricate botanical structure and the subtle but intricate differences between the different species. This was apart from the challenges they present as subjects in doing justice through graphite and watercolour to their growth habit, morphology and subtle hues.
Habitat
Viola odorata grows in hedge banks, woods and scrub. Although V. riviniana - can be found in the same habitats, it also grows in rocks and grassland. V. odorata is mainly restricted to calcareous soils.
Plant structure
Violet flowers have five petals- two side petals, two dorsal petals and a lip. A spur arising from the lower petal- faces backwards, this is large and deeply notched in the V. riviniana, whilst V.odorata‘s has no notch, is curved, approximately 6 mm in length and is a delight to draw. A single style and stigma, 5 stamens (two with nectaries). The blunt sepals each have a tiny appendage less than 1.5 mm in size in Viola odorata whilst V. riviniana’s are pointed with large appendages. The leaves of V.odorata are heart shaped, hairy in a manner described as ‘closely downy’ in the texts, and dark green in colour. Whilst those of the V. riviniana are longer in the stalk and cordate or somewhat more pointed/oval. Viola odorata propagates by runners (stolons) as well as seeds.
The differences between the two species appear subtle and small and to identify them takes close examination. To add to the confusion violets can hybridise and this presents further challenges and difficulties in identification.
Facts and uses
Sweet violets (V. odorata) are known for their scent, this is created by the chemicals, ionones, within the plant. I once spent a futile day trying to identify a white-coloured violet that had all the attributes of a Sweet Violet but was unscented. I had already found some purple Sweet Violets in the vicinity. So it may be that I had been influenced by a chemical within the flower, which blocks the ability to smell in humans.
After stimulating scent receptors, ionone binds to them and temporarily shuts them off completely. This substance cannot be smelled for more than a few moments at a time. Having already smelt the purple Viola odorata it may well have been the case that this chemical prevented me from smelling the scent of the white flowered form.
This is not exhaustive, but the little Sweet Violet leaves and flowers have a long history of use by humans in poetry, literature, flower symbolism, herbal medicine, sweet making, culinary uses, and romance. They are still popular as a flavouring and perfume in sweets. They were grown commercially in the southern counties of England, fields were given over to their propagation and harvesting in Cornwall and Devon, and transported to London for marketing.
These flowers have long been used in herbal medicine and traditional and modern perfumery.
The words elegant, delicate, pretty, purple hued can apply to violets of all species but the Sweet Violet tends to elicit high levels of admiration and poetry. “Shrinking violet’ is a term that does these hardy little flowers an injustice- they are among the first to flower in cold early spring even in harsh conditions and are alleged nuisances in gardens with their determined self-seeding.
Ecological value
Violets are an important larval food source for several species of Fritillary butterfly, including the threatened Pearl Bordered Fritillary, Boloria euphrosyne. Whilst humans can only smell the scent of the Sweet Violet, Fritillary butterflies are attracted by the scent of the Common Dog Violet too. They lay their eggs on the leaves and the larvae stage of the butterflies feeds on the plants.
Other animals closely linked to violets are ants and slugs. Both are attracted to a fleshy structure on the violet seed called the elaiosome, this contains fatty acids, proteins and sugars. Once eaten the undigested seeds are dispersed. The seeds require a period of cold temperatures for germination and must be sown from fresh seed. Across the globe, some species of violet may even have have co-evolved with distinct ant species and be dependant upon them for seed dispersal.
The position of the violets within their habitats- in coppice or semi shade on the edge of woodlands, or on heaths- are intricately interwoven with the breeding and feeding habits of the butterflies of each species. Reductions in environments due for example to lack of coppicing or removal of wood lands, or untimely verge trimming or removal of verges and hedgerows, therefore has an impact upon breeding colonies of these insects.
The complexity of these plants can only be briefly alluded to in this article. The violet is stunningly beautiful in its morphology and colour for the purposes of botanical art. Its importance as a food source or the animal species cited above is highly significant and ecologically vital.
In any event they are tiny jewels and I am really looking forward to observing and drawing them when next in season.
Sheelagh Keane
January 2020