WOOD SORREL FAMILY OXALIDACEAE 
LADY’S SORREL. SOUR GRASS 
Oxalis corniculata L. 
The Lady’s Sorrel is an herb, usually more or less hairy but 
sometimes smooth, that has become a common weed everywhere. 
Leaves and stems have an agreeable sour taste which accounts 
for the name Sour 
Grass. 
There are usually 
a few creeping stems, 
by means of which 
the’plant is perennial. 
The upright stems 
may be only a few 
inches high, and they 
bear the petioled, tri- 
foliate leaves whose 
leaflets fold at night. 
The plant blooms 
from early spring to 
late autumn and the 
small yellow flowers 
open only while the 
sun shines. Thecalyx 
consists of 5 yellow 
sepals, which remain 
on the fruit. There are 
5 yellow petals, 10 stamens and 1 pistil 
with 5 distinct styles. The mature fruit is 
nearly cylindrical but tapers toward the 
summit. Its 5 compartments have several seeds each. 
The Yellow Wood Sorrel, Oxalis stricta L., is a closely related 
species. In it the pedicels are turned downward as the fruits 
mature, but the pods themselves are erect. 
The Great Yellow Wood Sorrel, Oxalis grandis Small, is the 
most striking yellow-flowered species. It grows 1-4 feet high in 
rich moist woodlands and blooms from May to August. Stems 
and pedicels are thickly covered with bristly hairs. The entire, 
broadly heart-shaped leaves, notched at the tip, are hairy beneath 
and generally have a brown margin. There are 3 to several 
flowers with smooth yellow petals in each of the long-peduncled — 
inflorescences. 
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