Every Australian post in praise of an Oxalis starts with a reassurance that although some, such as Creeping Oxalis, are aggressive weeds of gardens and lawns, one shouldn't judge the whole genus by these miscreants.
And this is no exception, although you already know about the New Zealand Yam, remember. That out of the way, let me tell you Oxalis is a very big genus of about 800 species. Around half a dozen are native to Australia and another 20 or so are established as weeds (in your garden as well as native bushland).
My subject is Oxalis massoniana, from South Africa, via the Attila Kapitany's plant stall at the April meeting of the Cactus and Succulent Society of Australia in Mount Waverley. The Pacific Bulb Society record more than 200 species of Oxalis in South Africa, with another 270 varieties and probably many unnamed species as well.
My new orange-flowered oxalis has pretty flowers, each about one to two centimeters across. The famously 'trifoliate' leaf (in fact not all Oxalis have three leaflets - some have up to 10) is a little hard to decipher. You can see in these pictures that each leaflet is thin, curled in and upwards at the edges, and hairy. But look hard and you can see they are in groups of three.
Rare in its natural habitat in South Africa, it grows on a mountain plateau among sandstone boulders. Wet in winter but drying out in summer, when it's hairy folded leaves would help it lose less water.
According to Kew Gardens, the species was first cultivated in New Zealand and then, 15 years ago, brought into cultivation in London. It's recorded as growing in Kew's Davies Alpine House and I seem to remember the colour of its flowers there.
Like many (most?) Oxalis the flowers only open during the day. For the first few days I missed the flowers by heading to work during sunlight hours. Luckily the plant held its floral load until the weekend, when I took most of the pictures. This, however, if what greeted me each evening.
The appeal of this species to Royal Botanic Gardens Kew is in part because Francis Masson, the Scottish botanist after whom the plant is named, was a gardener there. His association with South Africa was through a collecting trip there in 1772 organised by Joseph Banks. He travelled around for 12 years, sending plant collections back to London.
So it's nice to honor Masson in the botanical name. But if its hard to remember, all Oxalis are called wood sorrels,some shamrocks, with the flower colour added to either. You can call this one the Pale Orange Wood Sorrel if you want.