Wood-sorrels
What are they?
Low-growing plants that can often carpet the ground in quite large patches. Flowers may be yellow, white or pink, with three-lobed leaves resembling those of clover (for this reason they are sometimes misidentified as 'Shamrock').
Where are they found?
Native species tend to like dappled shade in leafy woodlands, but introduced species are more often weeds or adventives of farm fields, gardens and urban areas. Some species will even grow from cracks in pavement.
Identification
Most species are fairly easy ot identify; some of the yellow-flowered species are rather similar and may need careful attention to stem hairs and/or seed pods.
Procumbent Yellow-sorrel Oxalis corniculata
(Creeping Wood-sorrel) A not uncommon species in urban areas where it grows as a weed in lawns, flower borders and even from cracks in pavement. Occurs in both green-leaved and purple-leaved forms. Flowers April to November.
 |
 |
|
 |
| |
|
|
(purple form) |
Upright Yellow-sorrel Oxalis stricta
(Upright Yellow Wood-sorrel) Widespread but local species, generally found in shady or wooded areas. Flowers May to October.
 |
 |
 |
|
| |
|
|
|
Slender Yellow-sorrel Oxalis dillenii
(Slender Yellow Wood-sorrel) Very common to abundant species of open fields and roadsides in Cape May County. Though considered to be a native species, its abundance in disturbed habitats suggests that its distribution may have changed under the influence of humans. Flowers May to July.
 |
|
 |
 |
| |
|
|
|
Pink-sorrel Oxalis articulata
Introduced from Europe. Uncommon as a garden escape. Flowers May to July or later. The leaves have orange spots on the underside.
 |
 |
 |
 |
| |
|
|
|