[Umbrian]

Thanks Mike for your comments. The clump was /is very scented so I had concluded odorata. I followed the thread and made copious notes but am still learning
The RHS book I use says that sororia is white but sometimes blue and there is a cultivar called "Freckles" that I had many years ago in England. A keen Italian plantsman friend gave me the plant in the photo and said it was sororia but it was not in flower when he gave it to me and this is the first time I have seen it in flower. The flowers are quite large - up to 3cm acros at the widest point and very beautiful. I would think it is a cross between odorata and sororia - would you agree?

[MikeHardman]

The RHS book is wrong in implying its typical colour is white; that should be violet-blue.
(...just checked it was not amongst my writings for the RHS... ...no; phew!)

3cm is larger than usual, but they do vary, partly depending on how well-grown they are.

I am sure yours is V. sororia f. priceana (as per my photo in the RHS Encyclopedia of Perennials, p.483). This is sometimes referred to as V. priceana (that is only a synonym), and has the common name 'confederate violet'. If you imagine the blue part being pink, then you have 'Alice Witter'.
The V. odorata x sororia hybrids can be recognized by looking at their horizontal stems (and by other factors, too, but the stems are always present). The horizontal stems of V. odorata are fairly thin stolons. Those of V. sororia are thicker and somewhat lumpy rhizomes. The hybrids are intermediate.

Have a look at this thread, which is ostensibly about V. sororia x odorata hybrids -
http://forums.gardenweb.com/forums/load/violet/msg0610001720709.html.
In there you'll see lots of comments, including names for various of the hybrids - eg. 'Governor Herrick', 'Bournemouth Gem', 'Mrs. Pinehurst' (we think 'Mrs Pinchurst' was a typo).
And note our helenaviolet's comment and photo showing a hybrid's leaf in comparison to those of ordinary V. odorata (that, too, is intermediate). Her next photo is of 'Governor Herrick'.

[helenaviolet]

Hi Umbrian; lovely pic of V.sororia 'Confederate Violet' and thanks Mike for the details and link to the Garden Web. V.sororiais a hardy and charming species to collect and grows well in pots.

3 pics here  1) 'Alice Witter'  2) 'Freckles'  3) plain blue one.   

[Alisdair]

Very interesting, Mike and Helena - thanks!

[MikeHardman]

Lovely piccies, Helena; thanks.

[Joanna Savage]

This little annual spontaneous viola appears every year and is becoming more prolific. Could it be sp. arvensis?.

[MikeHardman]

Cheerful little chap, Joanna.
No, he's not V. arvensis. If he were, when looking at the flower straight-on, you'd see the green sepals sticking out beyond the petals. Not sure what he is.
If you could say where you garden and tell me if you ever planted pansies/tricolors hereabouts, that might help...

[helenaviolet]

I am surprised here. Joanna, I would have thought yes, V.arvensis but Mike you do have keen observation. I checked through some pics of a tiny little white viola here which I believe to be V.arvensis. Well, you can see the green sepals sticking out - ?

[MikeHardman]

Yup Helena - V. arvensis - sepals just right.

Note that, just because it has 'front-visible sepals', it is not automatically V. arvensis. There are other, smaller white/cream pansies species that also have that feature, but their flowers are notably smaller (V. kitaibeliana, eg.).

[Joanna Savage]

Hello Mike, How long has it taken you to learn all these tiny facets about Viola? It is amazing what there is to be seen in one small plant. I garden in Toscana, on the southern slope of the Appenines at about 300 m. These little violas are very common in the fields around here, very occasionally they have a touch of blue colour. I have never planted pansies or violas, so if they are garden escapees they escaped generations ago.

[MikeHardman]

Joanna,

...How long? - Well, it has taken me over twenty years. So far...

Considering the location...
(V. hymettia is similar, but it has smaller flowers and occurs elsewhere.)
That leaves only two likely candidate species in your area: Vv. arvensis and tricolor (incl. ssp. subalpina).
See:
- http://luirig.altervista.org/flora/taxa/index1.php?scientific-name=viola+arvensis
- http://luirig.altervista.org/flora/taxa/index1.php?scientific-name=viola+tricolor
(Yes, I'm putting V. arvensis back into consideration for now.)

Blue in some of the petals: can occur in both species.
The 'protruding sepals' character is only one that should be considered, and it is not 100% reliable. If you can, have a go at seeing how your plants compare with the descriptions of the two species in this account -
http://www.floranordica.org/Review/-Review_public/accounts/Viola.html#arvensis
That might point towards one of these species, if you're lucky. However, characters often seem mixed.

One should also consider the hybrid V. tricolor X arvensis (V. X contempta). It is of intermeiate character, hence very tricky.

Sorry there isn't a quick and easy reliable answer; however, my feeling is for V. tricolor.

(Note: We discussed V. tricolor ssp. macedonica on this forum before - http://www.mgsforum.org/smf/index.php?topic=276.0. Although that plant looks very similar, it does not occur in your area.)

[Umbrian]

Fascinating stuff Mike and thanks. The flower I photograped was found growing through gravel under the shelter/shade of a low wall where I had placed the potted plant given to me in early summer before deciding where to put it. Obviously some seed fell and found the place to its liking. The parent plant is still only in bud.
Lovely 'photos Helena violet and the one of "Freckles" is just how I remember it from England.
Am downsizing garden shortly and feel that Violas will become a new favoutite with me

[Joanna Savage]

Thanks for your help Mike. I'll report back when I have done some homework.

[helenaviolet]

Hi Umbrian,
You will find a big ant in the wildlife section - here is a little one - struggling with a seed of Viola odorata (St.Helena violet). It is not surprising to see why violets suddenly appear in unexpected places. I deliberately moved the seed on to the leaf and this greedy little ant quickly set about retrieving its prize. Curiously, the St.Helena violet grows well in the hot summer weather where I live. Smallish and compact. Slow but easy to propagate from runners. However, inspite of several attempts I haven't been successful in germinating it from seeds. Maybe the ants will succeed? 
Cheers, H:)

[MikeHardman]

Great photostudy, Helena.

The thought is that the elaisosome (the white part on the side of the seed proper) is mimicking an ant larva/pupa. We can see there is a similarity in size and colour. But I think it goes deeper than that: the elaiosome actually smells right. All that means that, not only do ants sniff out the violet seeds (rather than just stumbling across them), they take them back to their nest - underground and in nice finely tilthed earth!
Because Viola odorata and related violets have evolved this strategy with ants as a means of dispersal, their seed pods lie on or near the ground and when they open, the seeds just tumble gently out. That's in contrast to other violets, such as V. riviniana, which accomplish dispersal by ballistic ejection of the seeds from the pods, which are held upright above the leaves. It is no coincidence that the seeds of the latter type of violet do not have elaiosomes.

Just to pick up on violet seed pods being 'held upright above the leaves'...
Most of the time, the top of the flower stem is turned over, so the flowers face somewhat downwards. That persists after the seed pod is formed. But, in species that use ballistics for seed dispersal, shortly before the pod starts ejecting seeds, the top of the stem turns up, thus aiming the pod at the sky to achieve furthest dispersal. You can see what I mean in the last photo in my article on Viola elatior.
http://www.mikehardman.com/plants/viola/elatior.htm

Because violets can spend quite a while in the 'fat pods' stage without the seeds being ripe, it can be tricky when it comes to collecting seeds. The trick is to wait until the pod turns up: that's the signal that the seeds are very nearly ready. Also, the pod's green colour may become yellowish or brownish. Then you can collect the seed pod; best done by nipping it off at the base of the stem - leaving the sap in the stem to allow a bit of final ripening. Put the pod+stems in a closed paper (not plastic) bag and wait. You'll hear the seeds pinging off the inside of the paper.