_Oxalis acetosella_
_Flowers_--White or delicate pink, veined with deep pink, about 1/2 in.
long. Five sepals; 5 spreading petals rounded at tips; 10 stamens, 5
longer, 5 shorter, all anther-bearing; 1 pistil with 5 stigmatic styles.
_Scape:_ Slender, leafless, 1-flowered, 2 to 5 in. high. _Leaf:_
Clover-like, of 3 leaflets, on long petioles from scaly, creeping
rootstock.
_Preferred Habitat_--Cold, damp woods.
_Flowering Season_--May-July.
_Distribution_--Nova Scotia and Manitoba, southward to North Carolina.
Also a native of Europe.
Clumps of these delicate little pinkish blossoms and abundant leaves,
cuddled close to the cold earth of northern forests, usually conceal
near the dry leaves or moss from which they spring blind flowers that
never open--cleistogamous the botanists call them--flowers that lack
petals, as if they were immature buds; that lack odor, nectar, and
entrance; yet they are perfectly mature, self-fertilized, and abundantly
fruitful. Fifty-five genera of plants contain one or more species on
which these peculiar products are found, the pea family having more than
any other, although violets offer perhaps the most familiar instance to
most of us. Many of these species bury their offspring below ground; but
the wood-sorrel bears its blind flowers nodding from the top of a
curved scape at the base of the plant, where we can readily find them.
By having no petals, and other features assumed by an ordinary flower to
attract insects, and chiefly in saving pollen, they produce seed with
literally the closest economy. It is estimated that the average blind
flower of the wood-sorrel does its work with four hundred pollen grains,
while the prodigal peony scatters with the help of wind and insect
visitors more than three and a half millions!
As self-fertilization is impossible, the showy blossoms of the
wood-sorrel are a necessity not a luxury; for the insects must not be
allowed to overlook them.
Every child knows how the wood-sorrel “goes to sleep” by drooping its
three leaflets until they touch back to back at evening, regaining the
horizontal at sunrise--a performance most scientists now agree protects
the peculiarly sensitive leaf from cold by radiation. During the day as
well, seedling, scape, and leaves go through some interesting movements,
closely followed by Darwin in his “Power of Movement in Plants,” which
should be read by all interested.
_Oxalis_, the Greek for sour, applies to all sorrels because of their
acid juice; but _acetosella_ = vinegar salt, the specific name of this
plant, indicates that from it druggists obtain salt of lemons. Twenty
pounds of leaves yield between two and three ounces of oxalic acid by
crystallization. Names locally given the plant in the Old World are wood
sour or sower, cuckoo’s meat, sour trefoil, and shamrock--for this is
St. Patrick’s own flower, the true shamrock of the ancient Irish, some
claim. Alleluia, another folk-name, refers to the joyousness of the
Easter season, when the plant comes into bloom in England.