CUCURBITACEAE--FRUITS FOR PEONS, PILGRIMS, AND PHARAOHS

CUCURBITACEAE, Gourd Family

An excellent example of a plant family with many useful species is the gourd family, the Cucurbitaceae. Anyone can easily learn to recognize cultivated members of this family by observing several conspicuous features.

  1. Vines, usually annuals, with five-lobed or palmately divided leaves having long petioles; leaves alternately arranged on the stem.
  2. Spring-like tendrils.
  3. Male (staminate) and female (pistillate) flowers ( unisexual flowers) on a single plant (monoecious).
  4. Flowers with five fused petals and five stamens (male) or an inferior ovary (female).
  5. Fruits large and fleshy, usually with a hard outer covering (a special type of berry termed a pepo).
  6. Seeds attached to the ovary wall (parietal placentation) and not to the center.
  7. Many large, fairly flat seeds in which the embryo has two very large cotyledons.

Species of cucurbits are native in most countries of the world, especially in the tropics, and they are now cultivated in every country, state, and province where crop plants can be grown in the summer (warm temperature), comprising an important starch resource in many regional diets. Edible species include cucumber, squashes, "pumpkins" (any large edible orange species of Cucurbita), gherkins, melons of all kinds, chayote, and a variety of palatable gourds. Most people think of a "gourd" as a fruit that is bitter, and there are many species in the family having fruits that are too bitter to eat. The seeds of many can be roasted and eaten, with or without salt, such as those of buffalo gourd (Cucurbita foetidissima), which were eaten by California Indians.

The earliest records of human use of edible cucurbits has come from Mexico; caches of seeds of squashes have been found from habitations older than 9000 years, and certainly by 5000 B.C. In the New World, squashes and pumpkins were used as a major food crop (planted) by native peoples and became a major part of the diet of the Pilgrims, apparently a prominent food at the first Thanksgiving feast and all subsequent ones. Cucurbita fruits have yellow or orange flesh, which is rich in carotenoids, the compounds humans need to make vitamin A and our visual pigment rhodopsin.

Finds in Egyptian tombs have revealed that sweet (sugar-bearing) cucurbits were being eaten by sophisticated cultures in the Old World during early times. Seeds of melons (Cucumis and Citrullus) found in these tombs suggest that the pharaohs were serving these fruits at their meals. Moreover, melons and cucumbers are found throughout Africa, so they were probably important early food crops of African peasants. Today the food markets of Africa have many forms of these cucurbits, as well as the New World species.

Cultivation of typical garden cucurbits is familiar to most people. Seeds are planted in the spring, the plant grows vigorously in warm and hot weather with plenty of water, and flowers form in summer to produce fruits in summer or early fall before frost. In many forms, the first-formed flowers on a plant are staminate (male), and this is why they never form a fruit. Several weeks later the pistillate (female) flowers will form, and enough male flowers will be present so that the pollen can be transferred by a bee to a female flower. In the genus Cucurbita, the commonly cultivated species are not able to cross with each other, so one can plant a cultivar from each of the four species without fear of developing hybrid seeds---seeds collected from a fruit should produce the same type of fruit in the next generation.

Researchers have wanted to breed species of Cucurbita to transfer features of one cultivar into another, but this is not possible by crossing the typical species. Researchers began using the unpalatable buffalo gourd as an intermediary, because it could be crossed with any of the common species. Consequently, genes from one cultivar can be brought into buffalo gourd and then potentially transferred to another species. Use of the buffalo gourd was also desirable in developing cucurbits that can live under conditions where water is scarce and temperatures are high, because this is a plant that comes from a dry, hot natural habitat.

In the Old and New World there was early use of dried pepos for other purposes. Of course, the warty gourds have been used as decorations, and the bitter meat of gourds has been used for medicines and fish poisons. But the large gourds of Lagenaria in particular became popular around the world as containers, e.g., as vessels for carrying water or other liquids, as dippers, as objects to conceal male genitalia, or as places to mix brews, such as tea (e.g., maté). In addition, many peoples have used gourds as parts of musical instruments because the dry fruits have good resonant properties when used with strings or as horns or percussion instruments, such as rattles, scrapers, marimbas, and drums. Many tribes carve and decorate gourds for the home or ceremonies, including ceremonial masks. The calabash pipe, ala Sherlock Holmes, and many native pipes and hookahs have been fashioned from the necks of gourds.

The greatest controversy among gourd lore concerns the bottle gourd or calabash, Lagenaria siceraria, which is also called the Pre-Columbian gourd. This is one of the plants that was used for containers in both the Old and New World before Columbus discovered America. Records of the fruits come from Peru (7000 B.C.), Thailand (7000 B.C.), Mexico (2700 B.C.), and Egypt (2500 B.C.), even though the genus Lagenaria is native to Africa! Some authors have used the bottle gourd as evidence that there was pre-Columbian cultural exchange. However, experiments have shown that dried, sealed bottle gourds can float for as long as two years in seawater without killing the seeds; it is likely that bottle gourds floated between the continents and were picked up in the New World and adopted for uses there. Interestingly, in western Africa (e.g., Nigeria), certain tribes use the gourd in an annual fishing festival in which the gourds are floated on the water. One fruit making a successful trans-Atlantic voyage to the coast of Brazil from Africa would have been sufficient to establish the plant in the New World.

Although most cucurbits have a tough "skin," i.e., a hard exocarp, some have a much thinner skin, so that they are perishable, such as the chayote (Sechium) of Middle America and certain squashes. Chayote grows as a large perennial vine, usually on trellises.

One of the most bizarre cucurbits is the loofah (Luffa spp), which is a native of Asia, probably India. The fruits are a foot or more in length. When the fruit dries, the outer covering becomes papery and falls away, the watery flesh of the mesocarp dries and disappears, and the seeds drop out, leaving behind the vascular bundles that once serviced the flesh. When moistened, this skeleton becomes a bath sponge that will not scratch the skin. Health nuts acclaim wonders of this sponge, such as the removal of cellulite.

tree gourd or calabash, Crescentia cajete, which is a native of Central America but is now widely planted around the world tropics. Despite its common name, calabash is not a member of the Cucurbitaceae; it is really a species of a completely different plant family in which catalpa is a member (Bignoniaceae). Tree gourds form as nearly perfect spheres without a neck, so that there is rarely any difficulty in distinguishing these from true gourds. The dried fruit walls (pericarp) are used by native Americans for bowls, vessels of various types, and instruments. This plant lives inland, not near the beaches, and is not native to many areas in the American tropics, where is was grown before Columbus arrived. Therefore, we can assume that this plant was purposely carried to the islands of the West Indies and parts of South America.

Commonly Cultivated Species of Cucurbits (Cucurbitaceae)

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