Oxalis purpurea L., Oxalidaceae

Click on an image for links to BIGGER PICTURES

Present on Pacific Islands?  yes

Primarily a threat at high elevations?  yes

Common name(s): [more details]

English: large-flowered oxalis, purple woodsorrel

Habit:  herb

Description:  "Apparently acaulous perennial, but with underground stem above bulb; bulb narrow-ovoid; outer scales dark brown or blackish, ± shining, viscid, with inconspicuous nerves. Leaves radical, 3-foliolate. Petiole (1)-2-10-(20) cm long, hairy; stipules 3-7 mm long, appearing as a broad wing, sometimes ciliate. Lamina of leaflets sessile, somewhat unequal, the terminal larger and 10-35-(45) x 1-37-(45) mm, broadly obovate, sometimes broader than long, glabrous above, hairy beneath and densely marked with short, black, glandular dashes when dry; margins long-ciliate; base cuneate; apex rounded; lateral leaflets somewhat asymmetric at base. Flowers solitary, erect; peduncles 1-11 cm long, hairy. Bracts 2-3 mm long, linear-subulate, usually in lower 1/2 of pedicel; calli 0. Sepals 6-7.5 mm long, elliptic, with longitudinal black streaks when dried, with dense long, white cilia, otherwise glabrous; calli 0. Corolla forming a deep cup 2.5-4 x 2.5-3 cm, with a lower, tubular part; petals 2-4 cm long, ± suborbicular, glabrous except for ciliate margins; lower part yellowish; limb usually rose or purplish, sometimes white flushed pink outside. Stamens at 2 levels, glabrous; filaments with broad membranous wing, often almost to apex in shorter stamens. Styles < or > longer stamen whorl, hairy. Capsule not seen"  (Webb et al., 1988; p. 922).

"A pubescent or villous stemless herb with a bulb that emits an ascending underground stem.  The stem forms a rosette of leaves and flower stalks at soil level.  Petioles are 3-10 cm long, the leaves are compound with three rhombic leaflets of 8-23 mm length and 9-30 mm width.  Leaflets are rhombic and often purplish beneath.  Flowers are pale yellow, white or rose-purple and borne solitary on peduncles of 1-10 cm length.  The corolla is 20-22 mm long.  The sepals are lanceolate, the petals purplish-pink and white at the base, and 25-35 mm long.  Fruits are capsules of c. 5 mm length"  (Weber, 2003; p. 295).  In New Zealand, "cultivation escape, generally in waste places near gardens or rough lawns, especially in cemeteries"  (Webb et al., 1988; p. 922).

Habitat/ecology:  "Grass- and heathland, shrubland, coastal beaches, disturbed sites.  This is a highly variable species within the native range with several varieties differing mainly in flower color.  The commonly naturalized form has rose to purple flowers.  The plant is invasive because it builds up dense colonies that displace native vegetation and reduce species richness.  Established population are persistent and highly competitive to native plants"  (Weber, 2003; p. 295). 

In New South Wales, Australia, "a weed in gardens, along roadsides and cemeteries, probably a garden escape"  (NSW PlantNET).  "In Chile this species grows in the following environmental conditions:  Low altitude, interior valleys; coastal mountains, 500-2000 m; coastal areas, 0-500 m. Dry, arid areas, with long drought periods of 6-10 months, precipitations of 100-300 mm. are concentrated in winter. Fully exposed to the sun, level areas or slopes facing north; some shadow, some protection against direct sunlight, some shadow from vegetation, filtering about 20-40% of light"  (Chileflora).

Propagation:  "The plant spreads mainly vegetatively by bulbs which are easily dislodged and dispersed"  (Weber, 2003; p. 295).

Native range:  South Africa (Cape Province, Transvaal), Swaziland (GRIN).

Presence:

Pacific
Country/Terr./St. & Island group	Location	Cited status & Cited as invasive & Cited as cultivated & Cited as aboriginal introduction?	Reference & Comments
Chile (offshore islands) Juan Fernández Islands	Isla Más a Tierra (Robinson Crusoe Island)	introduced invasive	Atkinson, Rachel/Sawyer, John (2011)
Chile (offshore islands) Juan Fernández Islands	Isla Más a Tierra (Robinson Crusoe Island)	introduced invasive	Danton, Philippe/Perrier, Christophe/Martinez Reyes, Guido (2006) (p. 556)

Pacific Rim
Country/Terr./St. & Island group	Location	Cited status & Cited as invasive & Cited as cultivated & Cited as aboriginal introduction?	Reference & Comments
Australia Australia (continental)	New South Wales	introduced invasive cultivated	National Herbarium of New South Wales (2013)
New Zealand New Zealand	New Zealand (country)	introduced invasive cultivated	Webb, C. J./Sykes, W. R./Garnock-Jones, P. J. (1988) (p. 922)
South America (Pacific rim) South America (Pacific rim)	Chile (Republic of)	introduced	Belov, Michail (2013)
United States (west coast) United States (west coast states)	USA (California)	introduced	U.S. Dept. Agr., Nat. Res. Cons. Serv. (2013)

Control:  If you know of control methods for Oxalis purpurea, please let us know.