Class 11 Biology

Important Families of Angiosperm


This family was earlier called Papilonoideae, a subfamily of family Leguminosae. It is distributed all over the world.

Vegetative Characters: Trees, shrubs, herbs, root with root nodules

Stem: Erect or climber

Trees and shrubs have erect stem, while herbs can be climbers.

Leaves: Alternate, pinnately compound or simple, leaf base is pulvinate, stipulate, venation reticulate.

Alternate phyllotaxy means leaves originate alternately from different nodes. Pulvinus means, the base of the pedicel is swollen. Stipulate means stipule is present near the base of pedicel.

Floral characters

Inflorescence: Racemose

Floral diagram of Fabaceae

Flower: Bisexual, zygomorphic

Calyx: Sepals five, gamosepalous, imbricate aestivation

Both androecium and gynoecium are present in bisexual flower. Zygomorphic flower or regular flower has radial symmetry. Gamosepalous means sepals are united with each other. Imbricate aestivation means that sepals overlap each other but there is no definite order of overlapping.

Corolla: Petals five, polypetalous, papilionaceous, consisting of a posterior standard, two lateral wings, two anterior ones forming a keel (enclosing stamens and pistil), vexillary aestivation

Androecium: Ten, diadelphous, anther dithecous. Diadelphous means anthers are in two groups. The floral formula of this family shows that one group has 9 anthers while second has 1 anther. Dithecous means anther has two lobes.

Gynoecium: ovary superior, mono carpellary, unilocular with many ovules, style single. In case of superior ovary, other floral parts grow on thalamus from a position that is below the ovary.

Fruit: legume, seed: one to many, non-endospermic

floral formula of fabaceae

Economic importance: Many plants belonging to the family are sources of pulses (gram, arhar, sem, moong, soyabean; edible oil (soyabean, groundnut); dye (indigofera); fibres (sunhemp); fodder (Sesbania, Trifolium), ornamentals (lupin, sweet pea); medicine (muliathi).


It is a large family, commonly called as the potato family. It is widely distributed in tropics, subtropics and even temperate zones.

Floral diagram of Solanaceae

Vegetative Characters: Plants mostly, herbs, shrubs and small trees

Stem: herbaceous rarely woody, aerial, erect, cylindrical, branched, solid or hollow, hairy or glabrous, underground stem in potato (Solanum tuberosum)

Leaves: Alternate, simple, rarely pinnately compound, exstipulate, venation reticulate

Floral Characters

Inflorescence: Solitary, axillary or cymose as in Solanum

Flower: bisexual, actinomorphic

Calyx: sepals five, united (gamosepalous), persistent, valvate aestivation

Persistent means sepals remain there even after the formation of fruit. You can see them at the base of an eggplant and tomato.

Corolla: petals five, united (gamopetalous), valvate aestivation

Both calyx and corolla apper like tube because they are gamosepalous and gamopetalous.

Androecium: stamens five, epipetalous. Epipetalous means stamens are attached to petals.

Gynoecium: bicarpellary, syncarpous, ovary superior, bilocular, placenta swollen with many ovules

Fruits: berry or capsule

Seeds: many, endospermous

Floral Formula

floral formula of solanaceae

Economic Importance: Many plants belonging to this family are source of food (tomato, brinjal, potato), spice (chilli), medicine (belladonna, ashwagandha), fumigatory (tobacco), ornamentals (petunia).


Commonly called the Lily family is a characteristic representative of monocotyledonous plants. It is distributed worldwide.

Floral diagram of Liliaceae

Vegetative characters: Perennial herbs with underground bulbs/corms/ rhizomes

Leaves: mostly basal, alternate, linear, exstipulate with parallel venation

Floral characters

Inflorescence: solitary / cymose, often umbellate clusters

Flower: bisexual, actinomorphic

Perianth: petal six (3+3), often united into tube, valvate aestivation

Androcium: stamen six, (3+3)

Gynoecium: tricarpellary, syncarpous, ovary superior, trilocular with many ovules, axile placentation

Fruit: capsule, rarely berry

Seed: endospermous

floral formula of liliaceae

Economic Importance: Many plants belonging to this family are good ornamentals (tulip, Gloriosa), source of medicine (Aloe), vegetables (Asparagus), and colchicine (Colchicum autumnale).