Families of Flowering Plants

Subfamily - Papilionatae (Fabaceae)

Inflorescence: Racemose or solitory axillary.

Flower : Bracteate or ebracteate rarely bracteolate (e.g., Arachis), pedicellate or sessile, complete, irregular, zygomorphic, perigynous or occasionally hypogynous, pentamerous.

Calyx : Sepals 5, gamosepalous, usually companulate, lobe unequal, rarely tubular (e.g, Cyamopsis), odd sepal anterior, may be persistent inferior.

Corolla : Petals 5, polypetalous, papilionaceous, descending imbricate aestivation, one posterior long standered, two lateral short wings, two anterior petals jointed to each other forming keel.

Androecium : Stamens 10, usually diadelphous (9+1 in Lathyrus, 5+5 in Aeschynomene) or monadelphous (9 in Dalbergia, 10 in Arachis and Erythrina indica), rarely free (e.g., Sophora), nectar gland often present on the inner bases of filaments, anther lobes bilocular, dorsifixed, introse.

Gynoecium : Monocarpellary, ovary superior, unilocular with marginal placentation ovary covered by staminal tube, style bent, stigma simple or capitate.

Fruit : Legume or lomentum.

Floral formula:
 

Solanaceae

Systematic position

Habit : Mostly herbs (Petunia, Solanum nigrum, Nicotiana, Withania), shrubs, a few trees (Solanum grandiflorum or potato tree) or climbers (Solanum jasminoides or potato vine, Solanum dulcamara).

Root : Branched tap root.

Stem : Usually the stem is erect, solid, cylindrical and branched. Occasionally, it is spinous (Solanum xanthocarpum, Datura stramonium, Lycium). In potato (Solanum tuberosum) underground stem is modified in to tubers.

Leaves : Cauline, ramal, exstipulate petiolate or sessile, alternate, sometimes opposite, simple, entire, pinnatisect in tomato (Lycopersicum esculentum). Venation unicostate reticulate, variegated in Solanum jasminoides.

Inflorescence : Axillary or extra axillary cyme. Solitary axillary in Physalis and Pentunia. Sub-sessile umbellate cyme in Withania somnifera, solitary in Datura.

Flower : Bracteate or ebracteate, pedicillate, complete, actinomorphic, rarely zygomorphic (e.g., Salpiglosis, schizanthus), bisexual, rarely unisexual (e.g., Withania coagulans) pentamerous, hypogynous.

Calyx : Sepals 5, gamosepalous, tubular or campanulate, persistent, accrecent (enlarging in fruit, e.g., Physalis, Withania), Valvate or imbricate, green or coloured, hairy.

Corolla : Petals 5, gamopetalous, tubular or infundibuliform, valvate, twisted in Datura, bilabiate in Schizanthus, scale or hair like outgrowth may arise from the throat of the corolla tube.

Androecium : Stamens 5, rarely 4 (e.g., Salpiglosis) or 2 (e.g., Schizanthus), free, epipetalous, polyandrous alternate to petals, filament inserted deep in the corolla tube, anthers dithecous, usually basifixed or dorsifixed, introrse.

Gynoecium : Bicarpellary, syncarpous, ovary superior, carpels placed obliquely in diagonal plane, generally bilocular (2-4 locular in tomato, 4-locular in Datura due to false septa), placentation axile, ovules many in each locules, placentae swollen, a nectariferous disc or lobes may be present, stigma capitate or lobed.

Fruit : A many seeded berry (e.g. Tomato) or capsule (e.g, Datura).

Seed : Endospermic with straight or curved embryo.

Floral formula :

Liliaceae

Systematic position

Habit : Usually perennial herbs growing by means of rhizomes (e.g., Aloe, Polygonatum), bulbs (e.g., Lilium, Allium) and corms (e.g., Colchicum). Some herbs are annual (e.g., Asphodelus). Shrubs occur in Aloe, Agave, Yucca (Dagger plants, Adam’s Needle), Dracaena (Dragon plant), and Ruscus (Butcher’s Broom). They mostly grow in arid areas and are hence xerophytic (e.g., Aloe, Yucca). Xanthorrhoea of Australia is tree-like. Climbers are seen in Smilax, Gloriosa and species of Asparagus.              

Root : Adventitious, fibrous or tuberous (e.g., Asparagus).

Stem : Erect or climbing as Smilex, branched or unbranched, herbaceous, phylloclade as Ruscus. Cladode as Asparagus, Bulb as Allium cepa.

Leaves : Radical or cauline and ramal, cauline and ramal show various types of phyllotaxy (alternate, opposite or whorled), exstipulate, stipulate in Smilax where the stipules are prolonged into tendrils, sessile or petiolate with sheathing leaf bases, venation parallel but reticulate in Smilax, leaves may be scaly, leathery, fleshy or modified into spines (e.g., Asparagus), leaf apex is tendrillar in Gloriosa. The leaves of Phormium tenax (New Zealand Hemp) are 3 metres long and 10 cm broad.

Inflorescence : Recemose, sometimes solitary (e.g., Tulipa, Gloriosa) or umbellate condensed cymes (umbel cyme), e.g., Onion. In several cases the inflorescence possesses a leafless peduncle called scape.

Flower : Bracteate or ebracteate, pedicellate, regular, actinomorphic, zygomorphic in a few cases (e.g., Gilliesia), complete or incomplete, perfect, unisexual in Smilax and Ruscus, hypogynous, generally pentacyclic, trimerous (rarely bimerous or tetramerous). Accessory floral organs undifferentiated and collectively called perianth.

Parianth : Tepals 6, in two whorls of 3 each, free or fused, sepaloid or petaloid, scarious or membranous, aestivation valvate or imbricate, distinguished into calyx and corolla in Trillium, inferior.

Androecium : Stamens 6 (3 in Ruscus, 9–12 in Tofieldia), free (polyandrous) or monadelphous (e.g., Ruscus), arranged in two whorls, antiphyllous (antitepalous), may be epiphyllous (or epitepalous), anthers fixed variously (basifixed, dorsifixed, versatile), dehiscence longitudinal or by pores, inferior.

Gynoecium : Tricarpellary, syncarpous, ovary superior, trilocular with 2-many ovules in each locules, placentation axile, rarely parietal, styles united or separate, stigma free or fused, trilobed.

Fruit : A capsule (e.g., Asphodelus, Gloriosa) or berry (e.g., Asparagus).

Seed : Endospermic and monocotyledonous.

Floral formula :

Cruciferae (Brassicaceae)

Systematic position

Habit : Annual, biennial or perennial herbs. Farsetia jacquemontii is an undershrub. The plants possess pungent juice having sulphur-containing glucosides.

Root : Tap root alongwith hypocotyl is swollen in Radish (Raphanus sativus) and Turnip (Brassica rapa).

Stem : Erect, cylindrical, hairy or glabrous, herbaceous or rarely woody. It is reduced in the vegetative phase in Radish and Turnip. The stem is swollen in Kohlarabi (Knol-Kohl = Ganthgobi, Brassica, oleracea var. Gonglylodes). Axillary buds enlarged in Brussel’s Sprouts ( = Button gobhi) or Brassica oleracea  var. gemmifera. Brassica oleracea var. capitata (Cabbage) has the largest terminal bud.

Leaves : Radical, cauline and ramal, alternate or sub-opposite but forming rosettes when radical, exstipulate with sheathing leaf base, sessile simple or rarely compound (e.g., Nasturium officinale), hairy. Bulbils occur in the leaf axils of Dentaria bulbifera and on the leaves of Cardamine pratensis.

Inflorescence : Flowers are usually arranged in racemose racemes. Occasionally they are in corymbs (candtuft).

Flower : Ebracteate or rarely bracteate (e.g., Rorippa montana), pedicellate, complete, perfect, regular, actinomorphic, rarely zygomorphic (e.g., Iberis, Teesdalia), tetramerous or bimerous, hypogynous (perigynous in Lepidium), cyclic, cruciform.

Calyx : Sepals 4, polysepalous, aestivation imbricate, generally arranged in two whorls, outer of antero-posterior sepals and inner of lateral sepals, lateral sepals generally saccate or pouched at the base, green or petaloid, inferior.

Corolla : Petals 4, polypetalous, arranged in one whorl and alternate with sepals, often with long claws and spread out in the form of a Greek cross. This arrangement of petals which is characteristic of the family is known as the cruciform arrangement and corolla is described as cruciform corolla, valvate aestivation. Petals reduced or absent in Lepidium and Rorippa.

Androecium : Stamens 6, (four in Cardamine hirsuta, two in Coronopus didymus, 16 in Megacarpaea), free (polyandrous), tetradynamous, arranged in two whorls, outer of two short lateral stamens while the inner whorl is made up of 4 long stamens arranged in two median pairs, anthers basifixed or dorsifixed, dehiscence longitudinal, inferior. Green nectaries are often associated with the bases of stamens.

Gynoecium : Bicarpellary (tricarpellary in species of Lepidium, tetracarpellary in Tetrapoma and Tropidocarpum), syncarpous, carpels placed transversely, ovary superior, placentation parietal, ovary bilocular due to the presence of a false septum called replum, style short, stigma capitate, simple or lobed.

Fruit : Siliqua of silicula, lomentaceous siliqua occurs in radish.

Seed : Non-endospermic, often oily.

Floral formula:

Malvaceae

Systematic position

Habit : Plants are annual herbs (e.g., Malva, Sida, Malvastrum, Urena) shrubs (e.g., Hibiscus rosa-sinensis, H. mutabilis) or rarely trees (e.g., Kydia, Bombax).

Root : Branched tap root.

Stem : Stem is erect, aerial, herbaceous or woody, usually solid, cylindrical and branched. Herbaceous portion of the stem is covered with stellate and scaly hairs; the woody part is fibrous. Plants usually have some mucilaginous substance.

Leaves : Leaves are alternate and stipulate (stipules 2, free lateral and often Caducous). They are simple and petiolate, lamina is sometimes palmately lobed (e.g., Gossypium) or digitate (e.g., Bombax). Venation is multicostate reticulate.

Inflorescence : Usually the flowers are solitary axillary or terminal. Occasionally, they are in panicle raceme (e.g., Kydia).

Flowers : Flowers are bracteate, bracteolate, actinomorphic, bisexual (unisexual in Kydia), pentamerous and hypogynous. The number of bracteoles varies from 3 to many, they form a whorl of epicalyx below the calyx. Sometimes the epicalyx is absent (e.g., Sida and Abutilon).

Calyx : Sepals 5, gamosepalous (connate at the base but free at the tip) and show valvate aestivation. Usually epicalyx present.

Corolla : Petals 5, polypetalous (slightly fused at the base), usually adnate at the base to the staminal tube. They show twisted or imbricate aestivation.

Androecium : It has indefinite stamens. They are monadelphous. Filaments of the stamens are united to form a long staminal tube or staminal column which encloses the style. Basal part of the staminal tube is fused with the petals; thus stamens are epipetalous. Anthers are monothecous, reniform, transversely attached to the filament and extrorse. In Bombax stamens are polyadelphaous.

Gynoecium : It is 2 to many carpellary. It is bicarpellary in Plagianthus, tricarpellary in Kydia, pentacarpellary in Hibiscus and Sida, ten carpellary in Althaea rosea and 15 – 20 carpellary in Abutilon indicum. All the carpels are fused (syncarpous) to form a single ovary. Ovary is superior, multilocular with one or more ovules in each chamber. The placentation is axile.

Style is usually long and enclosed in the staminal tube. Stigmas are as many as the number of carpels or double the number of carpels.

Fruit : Fruit is a loculicidal capsule (e.g., Gossypium, Hibiscus), schizocarpic capsule (e.g., Abutilon, Sida) or a berry (e.g., Malvastrum).

Seed : Seeds are albuminous. In Gossypium the seeds are pubescent, i.e., covered with hairs.

Floral formula :

Compositeae (Asteraceae)

Systematic position

Habit : Most of the plants are annual herbs (e.g., Chrysanthemum, Lactuca, Calendula, Helianthus, Tagetes). A few are shrubs (e.g., Artemisia, Pluchea lanceolata) or rarely trees (e.g., Vernonia arborea, Wilkesia, Leucomeris). Milkamia cordata is a twiner.

Root : Usually there is a tap root, but in Dahlia and Taraxacum officinale fasciculated roots are present.

Stem : Stem is usually herbaceous, erect, branched, solid, fibrous and sometimes with milky latex. In Jerusalem artichoke (Helianthus tuberosus) the stem is underground and tuberous. In Baccharis, it is winged like a leaf.

Leaves : Leaves are mostly alternate and occasionally opposite (e.g., Helianthus) or whorled (e.g., Eupatorium, Zinnia verticillata). They are exstipulate, petiolate, simple, pinnately or palmately lobed or compound (e.g., Dahlia, Cosmos). Venation is reticulate.

Inflorescence : Inflorescence is capitulum or head with an involucre of bracts at its base. The number of flowers in each inflorescence varies from 1000 (in large flowers of Helianthus) to 1 (in Echinops). Peduncle flat on which florets are attached.

Flower : Epigynous, usually pentamerous with reduction in certain whorls, hermaphrodite or unisexual complete or incomplete, tubular (actinomorphic) or ligulate (zygomorphic), bracteate or ebracteate.

(1) Ray florets : Towards periphery of head, sessile bracteate, pistillate or neutral, zygomorphic, ligulate, epigynous.

Calyx : Absent or hairy pappus or scaly, persistant.

Corolla : Petals 5, gamopetalous, ligulate, strap shaped.

Androecium : Absent.

Gynoecium : Bicarpellary, syncarpous, ovary inferior, unilocular, one ovule in each locule, basal placentation, style simple narrow, stigma branched.

Floral Formula :

(2) Disc florets : In the centre of head, bracteate, bisexual, actinomorphic, tubular, pentamerous, epigynous.

Calyx : Absent or pappus.

Corolla : Petals 5, gamopetalous, tubular.

Androecium : 2 stamens, epipetalous, syngenesious, dithecous, bilobed, introrse, filament free.

Gynoecium : Bicarpellary, syncarpous, ovary inferior, unilocular, single ovule in the locule, basal placentation, style single, short, stigma bifid.

Floral Formula :

(3) Neutral florets : Androecium and gynoecium both are absent. Remaining structures are similar to ray floret and disc florets.

Fruit : Cypsella.

Seed : Exalbuminous.

Floral formula : 
 

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