South African Oxalis Two

There are more than 200 species of Oxalis in South Africa and 270 varieties and probably many new species as well. The only handbook on the Southern African species, by Salter, is almost sixty years old and out of print so there are many challenges in identifying them. Cape Plants, a conspectus of the Cape flora of South Africa by Peter Goldblatt and John Manning lists 118 in the Cape Floral Kingdom but there is only a brief botanical description, location sometimes with habitat information, and time of bloom in this book.

South African species C are found on this wiki page.


Oxalis index - Miscellaneous Oxalis - Oxalis flava - Oxalis hirta - Oxalis obtusa - Oxalis pes-caprae - Oxalis purpurea - South African oxalis A-B - South African oxalis D-E - South African oxalis F-G - South African oxalis H-K - South African oxalis L-M - South African oxalis N-O - South African oxalis P - South African oxalis R-S - South African oxalis T-Z - South American oxalis


Oxalis callosa has trifoliolate leaves and rose-red flowers with a purple ring and a yellow tube. It is an especially beautiful South African species found on gravely soils from the Bokkeveld Mountains to the western Karoo. It blooms in the fall. Photo 1 was taken by Bob Rutemoeller, photos 2-3 were taken by Mary Sue Ittner. Photo 3 shows the bulbs on a 1 cm grid. Photos 4-5 were taken by Nhu Nguyen.

Oxalis callosa, Bob RutemoellerOxalis callosa, Mary Sue IttnerOxalis callosa bulbs, Mary Sue IttnerOxalis callosa, Nhu NguyenOxalis callosa, Nhu Nguyen

Oxalis cathara has large flowers on long pedicels. Photo taken by Nhu Nguyen.

Oxalis cathara, Nhu Nguyen

Oxalis caprina described as a weed by some, grows from the southwest Cape to the Eastern Cape. It has trifoliolate leaves and 2 to 4 flowers lilac to white flowers per stem. It has a long bloom period. Photos by Mary Sue Ittner. The last shows the bulbs on a 1 cm grid.

Oxalis caprina, Mary Sue IttnerOxalis caprina, Mary Sue IttnerOxalis caprina bulbs, Mary Sue Ittner

Oxalis clavifolia is a low growing rambling plant when grown by me, but according to the literature it should be erect when growing in its native south and western Namaqualand. The flower is a brilliant yellow and with a purple margin on the underside. The stems are covered with viscous hairs, and the leaves club-shaped, giving rise to the latin name. Photos by Christiaan van Schalkwyk.

Oxalis clavifolia, Christiaan van SchalkwykOxalis clavifolia, Christiaan van SchalkwykOxalis clavifolia, Christiaan van Schalkwyk

Oxalis commutata is found on the plateaus of hills and in marshy places in the western Cape. It has short-stalked rounded to heart-shaped leaves in threes that are green above and smooth and reddish-purple below. This species has rose, lilac, or white flowers with a yellow tube held above the leaves. Photos by Mary Sue Ittner. The last shows the bulbs on a 1 cm grid.

Oxalis commutata, Mary Sue IttnerOxalis commutata bulbs, Mary Sue Ittner

MV5117, a plant collected by Michael Vassar at Vanrhynshoek, has lavender flowers held above the tiny leaves. It blooms in early fall, a few weeks after watering begins. Michael thought it to be this species. It increases rapidly so might need to be watched for weed status. Bulbs planted in the ground in Northern California are just hanging on however and not increasing. First photo by Mary Sue Ittner and second by Michael Mace.

Oxalis commutata MV 5117,  Mary Sue IttnerOxalis commutata MV 5117, Michael Mace

Oxalis comosa is common in Namaqualand, from Kamieskroon in the south, extending beyond Concordia in the North. The first photograph is of one from the Nababeep area (south of Springbok). It is one of the only few shade loving species, and if it grows among or in bushes can reach up to a metre in hight. Plants in sunny spots are much smaller and densely branched. The bulb is long and spindle shaped; the bulb tunics are light brown and smooth. Plants grown under this name are most often not this species, but rather the large flowered form of Oxalis obtusa, which can be distinguished by its totally different growth habit and bulbs. The first photo by Christiaan van Schalkwyk. The next two were taken by Bob Rutemoeller and Mary Sue Ittner in Namaqualand September 2006.

Oxalis comosa, Christiaan van SchalkwykOxalis comosa, Namaqualand, Bob RutemoellerOxalis comosa, Namaqualand, Mary Sue Ittner

Oxalis compressa is found in the Northwest to Southwest Cape and has more than one flower in the peduncle (2-6), trifoliate leaves and compressed leaf stalks and is often confused with Oxalis pes-caprae. For more information regarding this species and its look-alikes, see Oxalis copiosa below. The first photo is of a plant collected by Johannes-Ulrich Urban outside Vanrhynsdorp in hard gravel. It forms a rosette of bright green leaves with reddish-brown stems and many bright yellow flowers blooming above the leaves in winter. This plant, Oxalis sp. Uli63 , is most likely Oxalis compressa. The last photo shows the bulbs on a 1 cm. grid. Photos by Mary Sue Ittner and Bob Rutemoeller.

Oxalis compressa, Mary Sue IttnerOxalis compressa, Mary Sue IttnerOxalis compressa, Bob RutemoellerOxalis compressa bulbs, Mary Sue Ittner

The first photo below from Ron Vanderhoff shows a form with double flowers. The other photos of the leaves, back, and bulbs on a 1 cm grid of a double form donated to the BX by Alberto Castillo were taken by Mary Sue Ittner. It took many years of growing the bulbs before it bloomed. It may have benefited from a deeper pot.

Oxalis compressa, Ron VanderhoffOxalis compressa, double form, Mary Sue IttnerOxalis compressa, double form, Mary Sue IttnerOxalis compressa, double form, Mary Sue IttnerOxalis compressa, double form, bulbs, Mary Sue Ittner

Oxalis convexula is a winter spring bloomer with rosy-salmon flowers with a yellow throat. Leaflets are in threes, thick and fleshy. The flowers need warmth to open. The pictures below by Mary Sue Ittner December 2003 and January 2004 are taken on different days illustrating the leaves and open buds and on a second day the buds open even more. The third picture was taken after I brought it inside where it was warmer so the flowers would open. The fourth picture is of a plant four years after its last transplant. The original single bulb managed to form about 80 bulbs in these four years. In the last picture a part of this clump and some single bulbs can be seen on a 1 cm. grid. The thick fleshy stems seen in the first and fourth photos are characteristic of this species. The last two pictures were taken by Christiaan van Schalkwyk.

Oxalis convexula, Mary Sue IttnerOxalis convexula, Mary Sue IttnerOxalis convexula, Mary Sue IttnerOxalis convexula, Christiaan van SchalkwykOxalis convexula bulbs, Christiaan van Schalkwyk

Andrew Wilson has posted the following caution because of his experience in southern California with this species. "There, additional warmth is present and blooming begins in October or November. The plants form multiple small bulbils clustered about the axis of the flower stems. These are deposited on the ground below the plants and, in areas such as San Diego, they produce large numbers of plantlets either in spring or in the fall. If not destroyed, they produce within several months a new crop of flowering specimens. The temptation to permit this attractive species to bloom should be overcome as the weedy behavior can lead quickly to numbers that are difficult to contain." Tim Harvey, also living in Southern California, but more inland, had some planted in the ground for 7-8 years and reported it was definitely not invasive. To propagate it he had to save bulbils in the spring and plant in fall. He believed they did not survive the heat of summer. However, in his Accession Number inventory of Oxalis, Michael Vassar cautions that for each of the forms of this species listed there, many bulbils are formed. Michael lived and grew his plants just north of Los Angeles. Mary Sue Ittner in Northern California struggles to keep hers going and unlike many other species does not find there are extras to share with others. Diana Chapman who grows hers in pots in a very large greenhouse in Northern California does observe the bulbils and provides some useful guidance: " A tip for dealing with aerial bulbils produced by O. convexula and others. Vacuum them up before they have a chance to blow around." Christiaan van Schalkwyk reported that this species has never formed axial bulbs in his garden in South Africa, but noted that Salter in his monograph stated that it was such a vigorous plant, that it kept growing in between the pages of his press. He had to poison it in order to make herbarium specimens. So, the species seems to thrive under certain conditions, but not others. Photo from Mary Sue Ittner.

Oxalis convexula bulbils, Mary Sue Ittner

Oxalis copiosa is a yellow flowering species often confused with other similar species, namely Oxalis pes-caprae, Oxalis compressa and Oxalis haedulipes. All four have umbels of yellow flowers, although Oxalis copiosa has only 1 to 2 flowers per stalk, often only one flower in the beginning of the season, later progressing to two. If there is only one flower, one can still see the upper articulation of the flower stalk set at the bracts.

Oxalis compressa can be identified by the flattened or compressed leaf stalks. Oxalis pes-caprae has a brown bulb, without conspicuous longitudinal grooves. It may or may not have a stem. The bulbs of Oxalis copiosa and Oxalis haedulipes are similar: greyish and with conspicuous longitudinal grooves. Oxalis copiosa never has a stem, while Oxalis haedulipes always has an exserted stem. Below are photos of Oxalis copiosa from southern Namaqualand take by Christiaan van Schalkwyk.

Oxalis copiosa, Christiaan van SchalkwykOxalis copiosa, Christiaan van SchalkwykOxalis copiosa, Christiaan van Schalkwyk

Oxalis index - Miscellaneous Oxalis - Oxalis flava - Oxalis hirta - Oxalis obtusa - Oxalis pes-caprae - Oxalis purpurea - South African oxalis A-B - South African oxalis D-E - South African oxalis F-G - South African oxalis H-K - South African oxalis L-M - South African oxalis N-O - South African oxalis P - South African oxalis R-S - South African oxalis T-Z - South American oxalis


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Page last modified on February 24, 2016, at 09:56 AM