Simple Dry Fruits
Fruit:Fruit may be defined as a mature ovary which usually develops after fertilization, and consists of two parts, the pericarp developed from the wall of the ovary and the seed developed from the ovule. In the absence of fertilization, development of fruit is not possible and the ovary simply withers and falls off.
However, in some cases, the ovary grows into a fruit even in the absence of fertilization of the ovule. Such fruits are usually seedless or bear undeveloped seeds and are called parthenocarpic fruits, example banana, orange, apple, grape etc.
A fruit is normally formed by the growth of the ovary and is known as the true fruit. But in some cases, the thalamus or even the calyx may grow and form the major part of the fruit and such a fruit is called false fruit, example, Anacardium.
Classification of fruits:
Fruits may be broadly classified into three groups – simple, aggregate, and multiple or composite or compound fruits. Some of the common types under each group are discussed below:
When only one fruit is developed from a single flower having a monocarpellary or polycarpellary and syncarpous ovary, with or without accessory parts, it is said to be simple fruit. Simple fruit may be either dry or fleshy.
Simple Dry fruits:
These types of fruits have a thin, hard, dry pericarp and are again classified into dehiscent or capsular, indehiscent or achenial and splitting or schizocarpic fruits.
Dry Dehiscent or capsular fruits:
These are dry, many-seeded and dehiscent fruits. Capsular fruits may be of the following types:
- Legume or pod. This is a dry, dehiscent fruit developed from a unilocular superior ovary with marginal placentation. It dehisces by both ventral and dorsal sutures, as in Dolichos, Arachis and other leguminous fruits.
- Follicle: This is a dry, dehiscent fruit, developed from a unilocular ovary with marginal placentation. It this case dehiscence takes place by only one suture and mostly the ventral one, example, Calotropis.
- Siliqua: This is a dry long cylindrical fruit developing from a syncarpous, superior, bilocular ovary, with parietal placentation. At the beginning, the ovary is usually one chambered but later, it becomes two chambered due to the development of false partition wall called, replum or septum. It dehisces from the base towards the apex by both the sutures, for example radish, mustard.
- Silicula. It is a flattened and short form of siliqua and is as broad as long. Example,candytuft.
- Capsule: This is a dry many-seeded fruit developed from a monocarpellary or polycarpellary and syncarpous ovary which may be either unilocular or multilocular. It dehisces in many ways and almost all such dehiscent fruits developed from a syncarpous ovary are commonly known as capsule. Example, lady’s finger, cotton etc.
Dry Indehiscent or achenial fruits:
This group includes mostly single-seeded fruits which do not open at maturity. They are of the following types:
- Achene: This is a small dry and one-seeded fruit, developed from a monocarpellary, unilocular superior ovary. The pericarp of the fruit is tough and is free from the seed coat. Example, Mirabilis. Achenes usually develop from apocarpous ovary and therefore, they commonly occur in an aggregate as in Clematis.
- Caryopsis: This is a dry, small and one-seeded fruit, developed from monocarpellary, superior ovary. Unlike achenes, here the pericarp of the fruit and the testa of the seed are fused together as in Oryza.
- Cypsela: This is a dry, small, one-seeded fruit, developed from a bicarpellary, syncarpous and inferior ovary. The pericarp of the fruit is not fused with the seed coat. The fruit is usually provided with a crown of hairs called pappus. Examples, Tridax, Tagetes etc.
- Nut: This is a dry and one-seeded fruit, developed from a syncarpus superior ovary. The pericarp is hard and stony and is free from the seed coat as in Anacardium.
- Samara: This is a dry, one or two-seeded fruit with flattened wing-like outer growth developed from the pericarp of the fruit. The fruit is developed from a superior, bi or tricarpellary ovary as in Dioscorea. In some cases, the fruit consists of two samaras, separating when ripe and is called a double samara. In some cases, there are many dry wings, which are developed from the persistent sepals. Such fruits are called samaroid, example, Shorea.
Dry Splitting or schizocarpic fruits:
These are dry many-seeded indehiscent fruit developed from either superior or inferior syncarpous ovary. On maturity, these fruits split up into individual indehiscent one-seeded parts called mericarps. In some cases, however, the one-seeded parts are dehiscent in nature and are called cocci. Schizocarpic fruits of the following types.
- Lomentum: It is a dry, many-seeded legume-constricted or partitioned between the seeds into a number of one-seeded compartment. When the fruit matures the constrictions break to form many one-seeded part, example Acacia.
- Cremocarp: It is a dry, two-seeded fruit developed from an inferior bicarpellary syncarpous and bilocular ovary. On maturation, the fruit splits up into two indehiscent one-seeded mericarps. These mericarps remain attached to the top of the central exits called carpophore as in Coriandrum.
- Regma: It is a dry fruit developed from a tri or pentacarpellary, syncarpous superior ovary. Each fruit has as many number of chambers as the carpels, each known as a coccus. Like the cremocarp, these cocci remain attached to the carpophores and separate only when the fruit splits, as in castor.
- Carcerulus: It is a dry fruit developed from a bicarpellary or polycarpellary syncarpous superior and multilocular ovary. At the beginning, each locule contains many seeds but later due to the formation of false septa, it is divided into a number of one-seeded mericarps. In Ocimum sanctum, the ovary is bicarpellary and bilocular where as in hollyhock, it is polycarpellary and multilocular. In Malva, the fruit splits up into a number of mericarps.