In this essay we will discuss about the types of fruits. After reading this essay you will learn about:- 1. Simple Fruits 2. Aggregate Fruit 3. Composite or Multiple Fruit.
Essay # 1. Simple Fruits:
The fruits develop from the ovary of a solitary pistil in a single flower, e.g., pea, Pisum sativum of Fabaceae; rice, Oryza sativa of Poaceae etc.
These fruits are divided into two types:
a. Dry fruits, and
b. Succulent fruits (Fleshy fruits).
a. Dry Fruits:
In this type, the pericarp of fruit is simple, dry, membranous, leathery or woody and is not differentiated into three layers.
The dry fruits are divided into the following three types:
1. Dehiscent,
2. Indehiscent, and
3. Schizocarpic fruits.
1. Dry Dehiscent Fruits (Split Open at Maturity):
The pericarp of the fruits rupture after ripening and then the seeds are dispersed.
These fruits are divided into the following five types:
i. Legume or Pod:
When the fruits develop from monocarpellary superior ovary, they are called legumes. Ovary has one locule and many ovules are arranged on marginal placentation. Mature fruits dehisce by splitting up along two sutures, one on each side, e.g., pea, Pisum sativum (Fig. 2.158A); French bean, Phaseolus vulgaris; hyacinth bean, Dolichos lablab of Fabaceae etc.
ii. Follicle:
The fruits develop like legume, but dehisce by splitting up along one suture. These are usually found in pairs or more than two in a group, e.g., Calotropis procera (Fig. 2.158B) of Asclepiadaceae, Catharanthus roseus of Apocynaceae etc.
iii. Siliqua:
The fruits develop from bicarpellary, syncarpous, superior ovary. Placentation is parietal. Initially ovary is unilocular, but later on it becomes bilocular by a persistent false septum, the replum. On maturity, the pericarp ruptures in two valves starting from base to apex, leaving the seeds attached to the replum. The fruit is more in length than breadth, e.g., mustard, Brassica nigra (Fig. 2.158C-C’) and many other plants of Brassicaceae.
iv. Silicula:
It resembles siliqua, but is short, flat and wide. Its length is same as, or shorter than breadth, e.g., shepherd’s purse, Capseila bursa-pastoris (Fig. 2.158D) and candytuft, Iberis odorata of Brassicaceae.
v. Capsule:
When the fruit develops from bi- or multicarpellary, syncarpous, usually superior (sometimes inferior — Canna indica of Cannaceae etc.) ovary, it is called capsule. The capsule generally opens by valves or pores.
The capsules may open in different ways (Fig. 2.160):
1. Septicidal Capsule:
In this type, the fruit splits into component carpels along with their line of union and thus the placentae become separated in the middle, e.g., Linum usitatissimum of Linaceae, Ricinus communis of Euphorbiaceae, Hibiscus esculentus (Fig. 2.159A) of Malvaceae etc.
2. Loculicidal Capsule:
In this type, the fruit splits along the middle of each carpel and thus the placentae are found along the united margins, e.g., Andrographis paniculata, Adhatoda vasica and many other members of Acanthaceae; Gossypium herbaceum (Fig. 2.159B) of Malvaceae etc.
3. Septifragal Capsule:
In this type, the fruit splits either in the septicidal or loculicidal manner, but the septa break and the placenta along with seeds remain in the middle, e.g., thorn apple, Datura metel (Fig. 2.159C) of Solanaceae; Oroxylum indicum of Bignoniaceae etc.
4. Porocidal Capsule:
In this type, the opening takes place by means of pores at the apices of the ripened carpels, e.g., opium poppy, Papaver somniferum (Fig. 2.159D) of Papaveraceae.
5. Pyxis or Circumscissile Capsule:
In this type, the dehiscence takes place along a circular horizontal line on the pericarp. The upper lid thus formed becomes detached and exposed the seeds, e.g., Celosia cristata (Fig. 2.159E) of Amaranthaceae, Plantago sp. of Plantaginaceae.
2. Dry indehiscent Fruits (Achenial Fruits):
The fruits do not dehisce even after ripening and the seeds remain inside the fruits.
These fruits are divided into the following five types:
i. Achene:
The fruits develop from monocarpellary superior ovary. The fruits are unilocular and one-seeded. Pericarp is free from the seed coat and the seed is attached to fruit wall at one point only, e.g., Mirabilis jalapa of Nyctaginaceae, Rumex vesicarius of Polygonaceae, Nigella sativa (Fig. 2.161 A) of Ranunculaceae etc.
Usually achenes are found in groups, because they develop from multicarpellary apocarpous ovary, e.g., Nigella sativa, Clematis gouriana of Ranunculaceae.
ii. Caryopsis:
The fruits develop like achene, but the pericarp is inseparably fused with the seed coat, e.g., paddy, Oryza sativa; maize, Zea mays (Fig. 2.161 B) and many other members of Poaceae (Gramineae).
iii. Cypsella:
The fruits develop from bicarpellary, syncarpous, inferior one- chambered ovary. Pericarp is free from the seed coat, e.g., Marigold, Tagetes patula; sunflower, Helianthus annuus (Fig. 2.161C) and many other members of Asteraceae.
In many cases the fruits are attached with hairy pappus formed by the modification of calyx, e.g., Blumea lacera, Vernonia cinerea, Taraxacum sp. (Fig. 2.161D) of Asteraceae.
iv. Nut:
The fruits develop from bi- or multi-carpellary, syncarpous, superior ovary and the pericarp is leathery or woody, e.g., oak, Quercus sp. (Fig. 2.162 A, B) of Fagaceae; Sapindus trifoliatus of Sapindaceae; cashewnut, Anacardium occidentale (Fig. 2.162C,D); water chestnut, Trapa bispinosa (Fig. 2.162E) of Onagraceae etc.
The fruit of litchi, Litchi chinensis of Sapindaceae is also a nut, where a fleshy aril (funiculus) is present (Fig. 2.162F).
v. Samara:
The fruits are two- or more chambered and a few seeds develop from superior multicarpellary ovary where the pericarp is flattened into wings, e.g., chilbil, Holoptelea indica (Fig. 2.163A,B); maple, Acer sp. (Fig. 2.163C) of Aceraceae; lumber, Fraxinus americana of Oleaceae; Hiptage benghalensis of Malpighiaceae etc.
In many cases, the persistent calyx develops into wings. Thus the calyx helps in dispersal. These fruits are called samaroid. In this case, the ovary may be inferior (e.g., Combretum sp. of Combretaceae) or superior, e.g., Shorea robusta (Fig. 2.163D) of Dipterocarpaceae, Ulma sp. of Ulmaceae etc.
3. Schizocarpic Fruits (Splitting Fruits):
When the ripe fruits are divided into one- seeded segments (mericarps) and the segments do not rupture further, it is called Schizocarpic fruit.
These fruits are divided into the following four types:
i. Lomentum:
The fruits develop from monocarpellary superior ovary. It is a modified legume, which develops into one seeded mericarps by transverse constriction, e.g., Acacia nilotica (Fig. 2.164A), Arachis hypogea (Fig. 2.164B, B’), Mimosa pudica and many other members of Fabaceae.
ii. Cremocarp:
The fruits are bilocular and two-seeded; developed from a bicarpellary, syncarpous and inferior ovary. After maturation, it splits open from apex towards base into one-seeded indehiscent parts, the mericarps; which remain attached to the apex of the carpophore (the apically grown part of the thalamus), e.g., anise, Foeniculum vulgare (Fig. 2.164C); coriander, Coriandrum sativum and others of Apiaceae etc.
iii. Carcerule:
The fruits develop from bicarpellary syncarpous ovary. Due to formation of a false septum four one- seeded indehiscent locules, i.e., the mericarps, are formed, e.g., Salvia plebeja, Ocimum sanctum (Fig. 2.165A) of Lamiaceae.
In Hollyhock, Althea rosea (Fig. 2.165B, B’) of Malvaceae; the fruits are developed from multicarpellary ovary and, hence, the number of mericarps are much more.
iv. Regma:
The fruits develop from multicarpellary ovary and after maturation they divide into parts — as many as carpels. Each one-seeded part is called coccus. Thus the number of cocci is three in castor, Ricinus communis (Fig. 2.165C) of Euphorbiaceae and five in Geranium sp. of Geraniaceae.
b. Succulent Fruits (Fleshy Fruits):
The fruits usually remain succulent and juicy even at maturity. The pericarp of the fruit is differentiated into three layers: epicarp, mesocarp and endocarp. The mesocarp is thick, fleshy or fibrous. The fruits are indehiscent, thus the seeds are separated after the decay of fleshy tissue enclosing them.
These fruits are divided into the following seven types:
i. Drupe (Stone Fruit):
The fruits are generally one-seeded and develop from monocarpellary superior ovary. The pericarp is differentiated into an outer exocarp, a middle fleshy mesocarp, and inner hard (stony) endocarp, e.g., mango, Mangifera indica (Fig. 2.166A) of Anacardiaceae; peach, Prunus persica of Rosaceae etc.
Sometimes the fruit contains two seeds (developed in multicarpellary ovary) as in almond, Prunus amygdalus of Rosaceae, where the mesocarp is dry and tough. In palmyra palm, Borassus flabellifer (Fig. 2.166B) of Arecaceae, the drup contains three seeds, each has got a separate endocarp.
Sometimes the fruits are developed from multicarpellary syncarpous ovary, where the mesocarp is fibrous, hence it is called fibrous drupe, e.g., coconut, Cocos nucifera (Fig. 2.166C) of Arecaceae (Palmae) etc.
ii. Pome:
The fruits developed from the fleshy thalamus of syncarpous inferior ovary are called false fruit. Outer skin and flesh develop from the thalamus. True fruit is present inside the fleshy thalamus. Seeds are enclosed in thin ovarian wall. The fleshy thalamus is the edible part of the fruit, e.g., pear, Pyrus communis and apple, P. malus (Fig. 2.167) of Rosaceae, etc.
iii. Berry or Bacca:
The fruits are developed from the multicarpellary, syncarpous, superior or inferior ovary. Placentation is axile or parietal. The seeds lie embedded freely in the massive pulp developed from mesocarp and endocarp.
The epicarp remains as the outer thin covering of the fruit, e.g., brinjal, Solanum melongena (Fig. 2.168A); tomato, Lycopersicon esculentum (Fig. 2.168B) and many others of Solanaceae.
One-seeded berry is found in date palm, Phoenix sylvestris etc. [The date palm is usually considered as a one-seeded berry in which endocarp is thin and papery. But, it is also considered as a type of drupe, where the endocarp, instead of becoming hard and stony, has become papery.]
There are a number of Baccate or berry-type fruits which show some variation from the normal type.
These are:
1. Pepo:
The fruits are developed from tricarpellary, syncarpous, inferior ovary having parietal placentation. The exocarp is tough and the seeds are firmly attached to the placentae, e.g., cucumber, Cucumis sativa (Fig. 2.169A); gourd, Cucurbita maxima and many others of the family Cucurbitaceae.
2. Hesperidium:
The fruits are many-chambered, developed from the multicarpellary, syncarpous, superior ovary having axile placentation. The epicarp and mesocarp are fused together forming the skin, while the endocarp projects inwards forming distinct chambers. Many unicellular juicy hairs are present on the inner side of the endocarp, e.g., sweet orange, Citrus sinensis; lemon, Citrus aurantium (Fig. 2.169B) and many others of Rutaceae.
3. Balausta:
The fruits are many-chambered, many-seeded and develop from the multicarpellary, syncarpous, inferior ovary. The seeds have seed coat consisting of outer fleshy testa, forming the edible part, and inner hard tegmen. Seeds are irregularly arranged inside the fruit. The pericarp is rough and leathery with persistent calyx, e.g., Pomegranate, Punica granatum (Fig. 2.169C, C’) of Punicaceae.
4. Amphisarca:
The fruits are many-chambered, many-seeded and develop from the multicarpellary, syncarpous, superior ovary. Epicarp is hard; mesocarp and endocarp are fleshy — inside these seeds are scatteredly arranged. Mesocarp, endocarp and the swollen placenta are the edible parts, e.g., wood apple, Aegle marmelos (Fig. 2.169D) and elephant apple, Feronia limonia of Rutaceae.
Essay # 2. Aggregate Fruit:
A group of separate fruits develop from carpels (apocarpous) of one flower, e.g., Michelia champaca and Magnolia grandiflora of Magnoliaceae etc.
Actually the aggregate fruit is the collection of small fruits, known as etaerio of fruitlets. This collection of small fruitlets develops from a single flower with multicarpellary apocarpous ovary.
These fruits are divided into the following four types:
i. Etaerio of Follicles:
In this type, each free carpel develops into a fruitlet of follicle type and many such follicles are arranged in groups on the enlarged thalamus. This etaerio may consist of two (e.g., Calotropis procera of Asclepiadaceae; Catharanthus roseus of Apocynaceae etc.) or many (e.g., Magnolia grandiflora, Fig. 2.170A and Michelia champaca, Fig. 2.170B; of Magnoliaceae) follicles.
ii. Etaerio of Achenes:
The fruitlets are achenes. Many such achenes are arranged in different ways. In lotus, Nelumbo nucifera of Nymphaeaceae; the thalamus becomes spongy and achenes are embedded inside it. In Naravelia zeylanica (Fig. 2.170C, D), the achenes are aggregated on the thalamus and are hairy.
iii. Etaerio of Drupes:
The fruitlets are drupes. Many small drupes are arranged in groups on the fleshy thalamus, e.g., strawberry, Fragaria vesca and raspberry, Rubus idaeus (Fig. 2.171 A, A’) of Rosaceae.
iv. Etaerio of berries. The fruitlets are berries. Many such small berries are arranged on all sides of fleshy thalamus, where the apical part is fused with each other forming a common rind, e.g., mast tree, Polyalthia longifolia (Fig. 2.172A); Artabotrys odoratissima (Fig. 2.172B) and Anona squamosa (Fig. 2.172C, C’) of Annonaceae.
Essay # 3. Composite or Multiple Fruit:
When fruits develop from the complete inflorescence, they are called composite or multiple fruits, e.g., banyan, Ficus benghalensis and jack- fruit, Artocarpus heterophyllus of Moraceae etc.
These fruits develop from complete inflorescence. These are also called infructescences or syncarps.
These fruits are of the following two types:
i. Sorosis:
This type of fruit develops from a spicate pistillate inflorescence (spike, spadix or catkin), where the axis and the ovaries are fused together forming a single fruit, e.g., pineapple, Ananas comosus (Fig. 2.173A, A’ and B) of Brome liaceae; jackfruit, Artocarpus hetero phyllus (Fig. 2.173C, C’) of Moraceae.
ii. Syconus:
This type of fruit develops from hypanthodium or coenanthium inflorescence where the receptacle contains many seeds, e.g., fig, Ficus hispida (Fig. 2.174A, A’); banyan, F. enghalen sis of Moraceae.
