1. Varieties of Greens.--The leaves and stems of many young plants in
either their wild or their cultivated form are used for food. All of
them are similar in composition, but many of them differ in flavor and
appearance. The cultivated ones include beet tops, endive, spinach, and
kale, as well as lettuce, collards, Swiss chard, sorrel, mustard greens,
turnip tops, parsley, and cultivated cress and dandelion. The four
greens mentioned first are illustrated in Fig. 1, beet tops being shown
in the lower right corner; endive, in the upper right corner; spinach,
in the lower left corner; and kale, in the upper left corner. Commonest
among the wild greens are dandelion, cress, wild mustard, dock, pokeweed
sprouts, milkweed sprouts, and lamb's-quarters. Most of these wild
varieties are excellent in the spring when they are young and tender,
but it is not advisable to use them for food unless one is perfectly
familiar with their appearance.
2. Food Value of Greens.--The food value of all greens with the
exception of dandelion is very low, being just about equal to that of
celery and cucumbers. This may be increased in their preparation by the
addition of other food materials. However, the chief use of greens in
the diet is not to supply food value, but mineral salts, the most
important one being iron in a form that is necessary for building up
the blood.