buttercup oxalis
Oxalis pes-caprae L.


Oxalis pes-caprae is a small perennial herb in the Oxalidaceae (Oxalis family), native to the Cape Region of South Africa. Shoots of O. pes-caprae arise from a short vertical stem that is attached to a pale brown underground bulb. Each bulb (usually smaller than 1 in. [2.5 cm] in size) is capable of producing over 20 small whitish bulblets each year.
The trifoliate (clover-like) leaves arise from an enlarged basal stem tip, and are arranged in a loose basal rosette. Petioles are usually less than 4.7 in. (12 cm) long. Each leaflet measures less than 1.4 in. (3.5 cm) in length and are often spotted with hairy lower surfaces.
Flowers of O. pes-caprae are bright yellow and are arranged in umbel-like inflorescences. These inflorescences generally have fewer than 20 flowers each, with peduncles shorter than 11.8 in. (30 cm) in height. Sepals of O. pes-caprae are green, less than 0.28 in. (7 mm) long, lanceolate to oblong in shape, and the tips often have two orange or yellow tubercles. The yellow petals are clawed, less than 1 in. (2.5 cm) in length. Each flower has 10 stamens.
In North America, O. pes-caprae generally flowers from late fall to early summer, but fruits and viable seed have not been observed in California.
Ecological Threat
Oxalis pes-caprae, although widespread as a garden weed throughout much of California, has never before been observed invading natural areas in North America. It is now reported as invading native coastal dunes in northern California. Due to its extensive occurrence in lawns and gardens, O. pes-caprae has the potential to rapidly spread via the production of bulblets and contaminated soils into adjacent natural areas in California and elsewhere.

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EDDMapS Distribution

EDDMapS Distribution - This map is incomplete and is based only on current site and county level reports made by experts, herbaria, and literature. For more information, visit www.eddmaps.org

State Regulated List

State Regulated List - This map identifies those states that list this species on their regulated list. For more information, visit Invasive.org

Invasive Listing Sources

Taxonomic Rank

Kingdom: Plantae
Phylum: Magnoliophyta
Class: Magnoliopsida
Subclass: Rosidae
Order: Geraniales
Family: Oxalidaceae
Genus: Oxalis
Subject: Oxalis pes-caprae L.

Synonyms and Other Names

Other Common Names:
Bermuda buttercup, soursob, sour grass


Plants - Forbs/Herbs