Evolution of Seed Habit Part 7

Evolution of Seed Habit Part 7

Fabaceae: (Papilionaceae) Pea Family

A family of about 400 genera and 9000 species, the members of this family occurs all over the world, but particularly in the warm temperate regions. In Pakistan about 82 genera and about 587 species have been reported.

Familiar plants: Lathyrus odoratus (sweet pea), Arachis hypogeal (peanut), Cicer arietinum (chick pea) and dalbergia sissoo (shisham).

Fig 9.27 Fabaceae (Papilionaceae): Sesbania sesbar; A-twig; B-flower; B1 standard verillium; C-fruit a legume; D-carpel

Vegetative characters: habit: trees shrubs or herbs. Stem: herbaceous, or woody or climber by tendrils (wiry, coiled thread like structures). Leaves: compound or rarely simple, sometimes partially or completely modified into tendrils, alternate, stipulate; stipules mostly leafy.

Floral characters: Inflorescence: Racemose or solitary axillary. Flowers: bisexual,zygomorphic, bracteates, pedicellate, perigynous, pentamerous and papilionaceous.Calyx: 5sepals, more or less united in a tube, mostly hairy. Corolla: papilionaceous; petals 5, usually clawed, dissimilar; the upper posterior petal is large and conspicuous and is called standard or vexillum, 2-lateral ones free called wings and 2 anterior inner most that fuse to form a boat-shaped structure called the keel or carina. Androecium: stamens 10, mostly diadelphous (united by their filaments in 2 groups), 9 fused to form a sheath round the pistil, while 10^th posterior one is free. Gynoecium: a simple pistil, 1-carpeled, with 1-locule; ovary superior; ovary and style long, style bent at is bar, placentation (mono carpellary) marginal. Fruit: usually a legume or pod, showing a great variety of form in various species.

Economic importance: the family is of considerable importance as a source of high-protein food, oil, and forage as well as ornamentals and other uses. Main importance lies in the pulses, belonging to this family, which are used as food, some important and common species of pulse yielding plants are: gram, pea, kidney bean. These pulses are rich in protein contents.

Medicago sativa Alfafa is one of the world’s best forage crop for horses. Vicia, Melilotus and Trifolium are also cultivated as main fodder crops. Many trees of this family provide excellent timber for building, furniture and fuel. Main timber plants are butea. Dalbergia etc.

Seeds of arachis hypogeal peanut are edible and also used for extraction of peanut oil which after hydrogenation is used as a vegetable oil. Indigo dyes are obtained from indigofera tinctoria and butea monosperma, yielding yellow dye from flowers.

Many plants of this family are important for medicines: these include Glycyrrhiza glabra for cough and cold, and Clitoria ternatea is used against snake bite. The red and white seeds of abrus precatorious are used by jewelers as weights called “ratti”. Some important ornamental plants include lathyrus, lupines, Clitoria, butea etc.