Oxalis spiralis subsp. vulcanicola is a subspecies of Oxalis spiralis, a member of the wood sorrel family Oxalidaceae. This subspecies is also known as Velvet oxalis, 'Zinfandel', 'Burgundy' and 'Dark Form' to describe its dark foliage.
Oxalis spiralis ssp. vulcanicola (Volcanic sorrel) is a tender sprawling evergreen perennial to 8 inches tall by 2 feet or more wide with semi-succulent stems that spread to create a low, mounding mat of red foliage growing from small swollen tubers - will trail down over and drape a couple feet over an edge. It is semi dormant in winter with small rusty red to deep burgundy shamrock-like leaves emerging in spring along dark red stems that provide a great foil to the yellow flowers. In cooler or hotter locations it flowers in spring and early summer but in our mild coastal climate it is covered most of the year with attractive small five-petaled yellow flowers rising on delicate pink peduncles an inch or two about the foliage. The flowers have delicate red lines running down their throats the same color as the foliage.