These not discussed too much in chapter one. Stems provide support for the above ground parts of the plant. They also house the conduction system. Leaves are the usual site of photosynthesis in the plant.
Many different kinds of stems: Those of monocotyledonous plants are quite different from those of dicotyledonous plants. See figure p. 156 ff.
Banana stems, e.g., are actually the bases of leaves rolled together. The vascular bundles are scattered in plants such as corn but in circles in plants such as sunflower (see diagram on page 156).
Meristems -- areas of active growth. Primary meristems. Produce leaves, buds, stems, branches, and roots. Mainly responsible for increase in length. Secondary meristems. Produce tissues such as wood and bark. Mainly responsible for increase in diameter. See diagram on pg. 158.
Roots. Normally underground, but some are above ground. Some grow under water and others in air. Roots don't have leaf scars and axillary buds. Differ in many aspects of anatomy and physiology. Roots don't do photosynthesis (normally). They have root hairs to absorb water and dissolve nutrients. They have apical meristems but the pattern of growth is different from that in stems. See diagram pg. 160, 161.
Vascular cambium in center and surrounded by a pericycle. Outside the pericycle is the endodermis. Outside of the endodermis is the cortex. These cells often accumulate starch in their vacuoles. Then comes the epidermis.
In practice, roots vary a lot in the way they look although they have the basic structures described above. See page p. 160.
In many biennial species, we let the roots store up products for the second year and then harvest them at the end of the first (see pg. 162).
Table of leafy, root, tuber, rhizome, or bulbous crops on pg. 163.
These are not major in any culture but important in many. They add variety, minerals, vitamins, and fiber to the diet. They are usually low in starch, lipids, protein, and sugars. Many plant parts are eaten.

Edible Stems and Leaves.
There are thousands of plants that have been eaten in this manner in many different cultures. In the last few decades, several of them have achieved more significance although in some parts of the world minor cultivars are still widely grown. Many locally cultivated species are also utilized.
Table of production on pages 164-165. Important cultivated species listed pp. 166.

Store window with fruits and vegetables

The Brassicas
In most of the temperate parts of the world, the major group of cultivated leafy vegetables consists of members of the genus Brassica(Brassicaceae or Cruciferae). The seeds and roots of many of this group of plants are also utilized. These plants all contain mustard oil glycosides.
Many of these vegetables belong to a single species: Brassica oleracea. No good fossil evidence, but cultivated for at least 2500 years in S.E. Europe.
Forage kales (European black cabbage) are probably the forms that most closely resemble the original cultivars.

Common cabbage includes both red and green forms. Head cabbage has been known for many years also. Some about time of Christ. Modern headed cabbage originated about 1000 A.D. in Germany.
Often used to make sauerkraut. Goes back in orient for long time. Later introduced into Europe. Most members of this group very cold tolerant. Some cultivated cabbage relatives on page 168 in text.
Brussel's sprouts. Look like miniature cabbages. Selected from a mutant that appeared about 1750.
Kohlrabi. Exact origin not known.


Cauliflower and Broccoli.
Cauliflower known by Arabs in 12th century. Broccoli by at least 16th century in Europe. Both are derived from the immature inflorescences. In cauliflower most of the flowers are abortive.


Turnips, mustards, collards etc. are all eaten as "greens".
The young leaves are cooked and eaten directly. Turnips (Brassica campestris) and rutabagas (B. napus) are also Brassica species. An ancient crop. Appear in Indian writings of 2000 B.C. In Europe only about 12th century. Turnips are often eaten in Europe in the winter as that was about all that was available. Rutabagas have a stronger flavor. They may be derived from hybridization between cabbage and turnips. Rape or canola seed oil is also from other cultivars of this plant.

Radishes (Raphanus sativus) are also from the Brassicaeae. In the U.S., they are eaten as a garnish, but in other places, e.g., the Orient, they actually are important food items. 4000 years ago in Egypt. Very important in Japan. The large white radishes are called daikon. The ancestor of radishes not known with certainty.

Lettuce, chicory, and endive all belong to the Asteraceae (or Compositae). This is a large family with over 35,000 species. Sunflowers in this family also. Few are eaten by man.
Lettuce (Lactuca sativa) is an ancient species. Cultivated at least by 4500 B.C. in Egypt. Bitter tasting and was probably first domesticated as a medicinal plant. The Romans ate tossed salads with leafy lettuces. The wild ancestors are not known with certainty although Lactuca serriolais a possibility.
Many different cultivars have been selected.
Endives and chicories belong to the genus Cichoriumthat is closely related to Lactuca. The roots of chicory are roasted and used as a coffee adulterant. Blanched leaves of these and related species are used for salad greens, especially in Europe.


Carrots and their relatives.
The Apiaceae (or Umbelliferae) contains many plants used as vegetables. Among these are carrots, celery, parsley, parsley root, fennel, and parsnip.
In the case of celery (Apium graveolens), we use the swollen bases of the petioles. Celery has been cultivated since Greek and Roman times. Celery root is popular in Europe, but available here also.
Carrots ( Daucus carota) and parsnips ( Pastinaca sativa) are root crops of some importance. Carrot cultivars were originally purple and later yellow. Orange forms were selected later. Carrots probably were also domesticated for medicinal purposes. They contain carotene, which is a precursor for vitamin A. Parsnips similar except pale color instead of orange. They are sweeter tasting.
Parsley (Petroselinum sativum) is usually eaten fresh or as a garnish in the U.S. It is a major cooked vegetable in many Near Eastern cultures.


Beets (Beta vulgaris) are members of the Chenopodiaceae. The older types are usually called mangel or wurzel. Swiss chard is a cultivar of the petioles of the leaves. Sugar beets are forms that have been selected for higher sugar concentration.
Red beets are comparatively recent. Beets and chard have been eaten for thousands of years in the Near East and the Mediterranean area. The ancient Greeks mentioned these plants in their writings.
Bok choi is a Chinese form of Beta vulgaris that is commonly seed in Oriental grocery stores.
Spinach (Spinacia oleracea) is also a member of the Chenopodiaceae. Spinach is sometimes substituted for lettuce in salads. Native to western Asia. Domesticated after the time of the Roman Empire.

New Zealand spinach
This plant (Tetragonia expansa) is in the Aizoaceae and not the same family as spinach. It is eaten in much the same way.

In this case, the petioles are also eaten. This plant (Rheum rhaponticum,Polygonaceae) was also probably first domesticated for medicinal purposes.

Perennial green vegetables.
The artichoke (Cynara scolymus) is a member of the Asteraceae. The immature receptacles of the flowers and the bracts around them are eaten. See figure on page 176.
Popular in the Mediterranean area where they are native.
Asparagus (Asparagus officinalis) is in the lily family (Liliaceae). Also native to the Mediterranean area and North Africa. The young sprouts are eaten. See diagram on page 177.
Bamboo shoots (many species) are commonly eaten in the Orient.


Vegetables from bulbs
Onions, leeks, garlic, and shallots are all in the genus Allium of the Liliceae. All of these have been cultivated for thousands of years. Many species are wild harvested in many parts of the world.
Onions (Allium cepa) and garlic (A. sativum) probably originated in central Asia and leeks (A. ampeloprasum) in the Near Eastern center. All were cultivated in Egypt by 3200 B.C.
Chives (A. schoenoprasum) are eaten for the leaves alone. See the diagrams on page 179 in the text).


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Revised February 2005

© David S. Seigler, Integrative Biology 363, Plants and Their Uses, Department of Plant Biology, 265 Morrill Hall, 505 S. Goodwin Ave., University of Illinois, Urbana, Illinois 61801, USA. 217-333-7577.