Oxalis Identification needed

[TheOnionMan]

I've grown this oxalis for many years; I believe I once had a name attached to it, the name long gone now.  It flowers profusely in May with masses of brilliant flowers.  In the first photo, taken in low light, the flowers look lavender pink (also, I was using an old borrowed digital camera that had problems rendering certain colors accurately).  In the 2nd photo, catching afternoon sun, they look hot pink.  For the rest of the summer, it makes nice mats of foliage lasting all the way into autumn.  It flowers best when receiving some sun, but it really likes to spread around in shade (you can see a clump of foliage in the 4th photo showing a woodland garden scene).  While it does spread, it doesn't seem to do other plants any harm.

[Diane Clement]

I was just sorting out some pictures out and came across this picture which is remarkably similar to your plant in the first picture.  It's a picture taken at Chesterfield show last year, of a pink form of our native woodsorrel, Oxalis acetosella "Aydon Castle" named after where it was found in Northumberland by John Richards.

[Lesley Cox]

I was going to suggest O. acetosella in a better than usual colour form. But isn't that species the absolutely appalling one, which gave Oxalis its feared and terrible name in the first place?

[Diane Clement]

I was going to suggest O. acetosella in a better than usual colour form. But isn't that species the absolutely appalling one, which gave Oxalis its feared and terrible name in the first place?   

O acetosella is lovely in woodlands, but I wouldn't risk it in loose in my garden.  I've got the pink version safely in a pot. 
But the weediest one here is non-native O corniculata, annual, camouflages itself on the soil, isn't it a NZ native

[Blue-bellied Frog]

Is it that one?
O. montana, syn. O. acetosella

[Lesley Cox]

I am deeply sorry to have to admit that O. corniculata IS a NZ native, which I didn't know until I've just looked it up in the Flora. An absolute pest as you say Diane, but listed in the Flora as a perennial and certainly is such where I've had it in the past, in a couple of gardens, but not, thank the Lord here. It climbed and shimied through every cushion and mat and was almost a solid carpet in one driveway, and of course has very brittle stems so can't easily be traced back to the (mercifully) non-bulbous centre. A great seeder too.

[Maggi Young]

Well if we're talking about that little white flowered blighter.... tiny thing.... I can tell you it is perfectly perennial here!

 The yellow one with the bronze foliage... is that O. corniculata ?...... may not be.... I'd give it the benefit of the doubt and say it acts like an annual.
 

What is the name of the tiny white one... it is from NZ, I'm sure....

[TheOnionMan]

Is it that one?
O. montana, syn. O. acetosella

Bernard, your message, and a previous message from other posters, jogged my memory  

I've only ever received Oxalis in the past under two names, O. acetosella, and O. montana, I probably should've mentioned this.  Before posting this ID plea, I spent some time googling both names and a few other names, and it seemed to me that most photos of O. acetosella showed light pink flowers that were strongly striated or striped, whereas mine are a much deeper and more solid color.  If I were to bet on which name seems most prevalent in my brain, it is O. montana, but here again, the google searches yeilded hits and photos that didn't look nearly as wonderful and floriferous as my plant. 

I haven't heard that O. montana is synonymous with O. acetosella, the most I've seen is reference to montana being a subspecies of acetosella, or kept as a distinct species.  The large mats you see in my photos, took 20 years to get this big, so it's no thug here, whatever its identity is. A friend of mine has given me woodland plants that have what appear to be the same species mingling with the donated plants, and she has noticed that the leaves are bigger and taller on hers as compared to mine, but otherwise similar, and perhaps a bit more spreading.  I upload a closeup photo of my Oxalis for a better look at the flowers.

[Blue-bellied Frog]

Mark,
Maybe you have a beautiful variant?
In this link, if I read right, The O. montana is the accepted name.
http://www.itis.gov/servlet/SingleRpt/SingleRpt?search_topic=TSN&search_value=29090

But I don't want to start a war.
Botanists were created for that.

[Roma]

Maggi,
is Oxalis magellanica the white one you are thinking of?

[Lesley Cox]

Oxalis corniculata is the beastly little yellow flowered one and there is also a purple-leaved form. The flowers are tiny, much smaller than magellanica and it spreads by seed and long thin stolons. It's just about impossible to get the root of the thing when it has seeded into, say, a Draba or Saxifraga.

O. magellanica is native to both South America and New Zealand and not actually seen that much in our gardens but we sometimes come across a double form of it. It too, is quite rampant.

Not fair that we in NZ have the beastlies while S. America has the enneaphyllas, laciniatas, and other fabulous plants.

[Maggi Young]

Maggi,
is Oxalis magellanica the white one you are thinking of?

Thank you, Roma.... yes, that's the little swine  .... couldn't remember the name...

[TheOnionMan]

Mark,
Maybe you have a beautiful variant?
In this link, if I read right, The O. montana is the accepted name.
http://www.itis.gov/servlet/SingleRpt/SingleRpt?search_topic=TSN&search_value=29090
But I don't want to start a war.
Botanists were created for that.

Bernard, I think you're correct.  I should've studied up on this more before posting. 

It seems that in early USA taxonomy, the American "wood sorrel" was at first considered synonymous with the European species, O. acetosella. In my copy of An Illustrated Flora of the Northern United States, Canada and the British Possessions by Nathanial Lord Britton and Addison Brown, 1897, of the eight Oxalis species described, only two are white, pink, or rose-purple; O. acetosella and O. violacea, all the other species are yellow.

I know my plants cannot be O. violacea, as that species has several flowers per peduncle, whereas in O. acetosella and O. montana, only one flower per peduncle.  I finally found a decent image of O. violacea on an herbal site, the flowers looking more like my plant, except it shows multiple flowers per peduncle, so is not my plant.
http://www.altnature.com/gallery/Violet_Wood_Sorrel.htm

Looking around on the web, it seems rather unanimous that the American plant is properly identified as O. montana, as separate from the European O. acetosella.

http://www.fs.fed.us/database/feis/plants/forb/oxamon/all.html

The site above references two color forms of O. montana, but no description about what those two color forms are.  Here's what it says:

TAXONOMY :
The currently accepted name of common woodsorrel is Oxalis montana Raf.,
in the woodsorrel family (Oxalidaceae).  There are no recognized
subspecies or varieties.  Common woodsorrel is closely related to the
European species Oxalis acetosella.  Some earlier authors included
common woodsorrel as a variety of O. acetosella [10].  However, common
woodsorrel currently is recognized as a distinct species.  Two forms
based on flower color are infrequently used [10]:

        O. m. f. montana
        O. m. f. rhodantha Fern.

The USDA link below shows the distribution of O. montana, although once again I find photos of mostly white flowers strongly striated pink, not the solid color as in my plants.
http://plants.usda.gov/java/profile?symbol=OXMO

The taxonomy on O. acetosella is much more complicated than I thought, with more than 20 variety names and combinations, with a range far more extensive than I was aware (grows in China, Pakistan, much more than just Europe).

So, either I have an excellent color form of O. montana, or perhaps it is a form of O. acetosella, I believe the juty is still out on this one.

[Stephenb]

Didn't see this thread before. Oxalis acetosella is a wild plant in my garden and is called Gjøksyre in Norwegian or Cuckoo Sorrel, but it's flowering precedes the first cuckoos by around two weeks in this area. This is one of the few wild plants that kids know are good to eat (like sorrel), at least the last generation of kids - it's stems quench the thirst. Anyway, I digress - it's a "mild" weed here invading in deep shade around the feet of perennials as in the first picture where it's found its niche under one of my collection of nettles and I'm quite happy with that!   

I've had Oxalis acetosella purpurea several times from the seed exchanges, but it's either not germinated or died the first winter. I finally had success with one I obtained as "rosea" (second picture).

I have another attractive one (third picture) with purple underneath the leaves. Anyone know what species this is?

[TheOnionMan]

I never followed up or "closed" my findings on this thread, but I did hear from the person that gave the plant in the first place and they say it is O. acetosella.  Obviously mine is a deep pink form, and glad to see your photo of O. acetosella "rosea", which looks much like my plant.  It is mildly invasive, but since it only grows in the top 1/2" of soil, it doesn't really bother me, nor does it seem to bother plants it mingles with, it is easy to pull out unwanted plants.  The soft low clouds of foliage are very attractive the rest of the growing season.

I don't know what your last Oxalis might be.