Important Families of Angiosperm
Fabaceae
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
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
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).
Solanaceae
It is a large family, commonly called as the potato family. It is widely distributed in tropics, subtropics and even temperate zones.
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
Economic Importance: Many plants belonging to this family are source of food (tomato, brinjal, potato), spice (chilli), medicine (belladonna, ashwagandha), fumigatory (tobacco), ornamentals (petunia).
Liliaceae
Commonly called the Lily family is a characteristic representative of monocotyledonous plants. It is distributed worldwide.
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
Economic Importance: Many plants belonging to this family are good ornamentals (tulip, Gloriosa), source of medicine (Aloe), vegetables (Asparagus), and colchicine (Colchicum autumnale).