Viola canina [Heath Dog-Violet]

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Rørslett, B. 2012. Viola canina L. (Violaceae). Heath Dog-Violet. Flowers photographed in visible and ultraviolet light. http://www.ultraviol...ath-dog-violet/

 

Viola canina L.

NO: Engfiol (ssp. canina)

SE: Ängsviol; hundviol

DK: Hunde-Viol

FI: Aho-orvokki

IS: Týsfjóla

DE: Hunds-Veilchen

EN: Heath Dog-violet; Dog violet

 

This early-flowering, small violet is native to Europe and widely distributed in open grassland and along forest edges. Several more or less distinct races exist and traditionally at least the bigger-growing V. canina ssp. montana (L.) Hartm. is kept as a separate species (V. montana L.), but there are much transgressions between the extremes of the variation range and subspecific ranks likely are justified. V. canina easily hybridises with species such as V. persicifolia Schreb., V. riviniana Rchb., and V. rupestris F.W. Schmidt so identification of specimens at times can be pretty difficult. In particular the hybrid V. canina x riviniana (V. x interstita Beck) is often seen as the parents tend to grow in separate but adjacent habitats.

 

Being a common early-flowering plant, the dog violet is eagerly visited by pollinators such as bees and bumblebees.

 

I availed myself of a sunny, calm day to capture the pictures shown below. Specimens were found in Aurskog-Høland, South Norway, near the Swedish border. 18 May, 2012.

 

Visible light: Nikon D800, Micro-Nikkor 105 mm f/2.8 AIS lens,

 

Ultraviolet light: Panasonic GH-2, Coastal Optics 60 mm f/4 APO lens, Baader U 2" (Venus filter), daylight (hence short depth-of-field as the lens was used wide open).

 

The dog violet, like other violets, have patches of conical cells distributed more or less haphazardly all over the corolla. We see these as greyish silky-velvety areas on the petals. If there is a common distribution pattern to these within the flowers I have yet to observe that on all the dog violets photographed so far.

 

Buds, foliage, and stems, are all UV-dark for this species.

 

[Published: 26 Dec 2012]

[Andrea B.]

Interesting. Usually I see this reflective patchiness from conical cells as a function of the angle of the light (as on some Ranunculus or Papaver). But not here. It does cause the Violets to stand out against the dark stems and leaves. Perhaps these Violets are just trying to give the bees some footing. "-)

 

Added: I worked on my Allium tuberosum files today and found a similar random patchiness in the UV. http://www.ultraviol...-garlic-chives/