11th Class

Systematic position         Division      :         Angiospermae         Class            :         Dicotyledonae         Subclass     :         Gamopetalae         Series          :         Inferae         Order          :         Asterales                     Family         :         Compositae (Asteraceae)                                     (Largest family among the angiosperms) 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 more...

Systematic position         Division      :         Angiospermae         Class            :         Dicotyledonae         Subclass     :         Polypetalae         Series          :         Thalamiflorae         Order          :         Parietales         Family         :         Cruciferae (Brassicaceae) 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 Kohlrabi (Knol-Kohl = Ganthgobi, Brassica oleracea var. gongylodes). 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), more...

Systematic position         Division      :         Angiospermae         Class            :         Dicotyledonae         Subclass     :         Polypetalae         Series          :         Calyciflorae         Order          :         Passiflorales         Family         :         Cucurbitaceae Habit : These are trailing or climbing annuals or perennial herbs. Rarely they are shrubs (e.g., Acanthosicyos) or trees (e.g., Dendrosicyos). Stem : Herbaceous, branched, pentangular, fistular, tendrils in axil of leaf or opposite to leaves. The morphological nature of tendril is of dispute. Leaves : Leaves are cauline and ramal. They are alternate, exstipulate, simple, petiolate and cordate (e.g., Cucurbita maxima, Coccinia grandis) or deeply palmately lobed (e.g., Luffa cylindrica, Cyclanthera pedata). Venation is reticulate multicostate. Inflorescence : Flowers are either solitary axillary (e.g., Cucurbita, Coccinia) or in cymose clusters (e.g., Cucumis, male flowers of Luffa). Most of the members of the Cucurbitaceae are monoecious but a few are dioecious (e.g., Coccinia cordifolia, Trichosanthes dioica). Flower : Flowers are bracteate or ebracteate, pedicellate, more...

Dispersal by wind (Anemochory) The wind is probably the most important agency of seed dispersal in nature. The fruits and seeds show following devices which help in dispersal by wind. Light weight and minute seeds : Seeds of some plants (e.g., Orchids) are sufficiently light and minute in size to be easily carried away to great distances by air currents. Winged seeds and fruits : Some seeds (e.g., Oroxylon, Cinchona, Moringa) or fruits (Acer, Hiptage, Terminalia, Dipterocarpus) develop one or more thin membranous wings to ensure their dispersal by wind. Parachute mechanism : In members of the family Asteraceae (Compositae) e.g., Taraxacum, Sonchus, sepals are modified into tufts of hairs called pappus. The pappus is persistent and hence found attached to even small, single seeded fruits. It acts like a parachute that allows the wind to carry them to great distances. Seeds of many nasty weeds are also dispersed by more...

Formation of fruit : Fruit is defined as fertilized ovary. The ovary develops into fruit. The ovary wall at maturity forms the wall of the fruit, which is known as pericarp. Sometimes, other parts of flower such as tepals, (e.g., Morus), bracts (e.g., Ananas) or thalamus (e.g., Pyrus) are also involved in the formation of fruit and such fruits are called false fruits or pseudocarps. The fate of various parts of the ovary during the formation of fruits is summarized below :   Types of fruits They are classified into three groups : Simple, aggregate and multiple or compound fruit. Simple fruits : They are formed from mono-or polycarpellary but syncarpous ovary. They may be dry or fleshy. (1) Simple dry fruits have thin, hard and dry, pericarp. They are of three kinds : (i) Dehiscent or Capsular  (ii) Achenial or Indehiscent  more...

Systematic position Division      :         Angiospermae         Class            :         Dicotyledonae         Subclass     :         Polypetalae         Series          :         Calyciflorae         Order          :         Rosales         Family         :         Leguminosae Habit : Annual or biennial, herb, shrub or tree. Root : Tap root system. Stem : Erect or creeping, solid or weak. Leaf : Alternate or whorled, stipulate, petiolate, simple or usually compound, reticulate venation. On the basis of inflorescence and flower characters, this family is divided in to 3 subfamilies :   Subfamily - Papilionatae (Papilionaceae) Inflorescence : Racemose or solitary axillary. Flower : Bracteate or ebracteate rarely bracteolate (e.g., Arachis), pedicellate, complete, irregular, zygomorphic, hypogynous, pentamerous. Calyx : Sepals 5, gamosepalous, usually campanulate, lobes unequal, rarely tubular (e.g., Cyamopsis), odd sepal anterior, may be persistent, inferior. Corolla : Petals 5, polypetalous, papilionaceous, descending imbricate aestivation, one posterior long standard, two lateral short wings, two anterior petals jointed to each other forming keel. Androecium more...

Systematic position         Division      :         Angiospermae         Class            :         Monocotyledonae         Series          :         Coronarieae         Order          :         Liliales         Family         :         Liliaceae 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 show various types of phyllotaxy (alternate, opposite or whorled), exstipulate, stipulate in Smilax where the stipules are prolonged into more...

Systematic position         Division      :         Angiospermae         Class            :         Dicotyledonae         Subclass     :         Polypetalae         Series          :         Thalamiflorae         Order          :         Malvales                      Family         :         Malvaceae 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 system. 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 or more...

Development of seed : The fertilized ovule forms seed. The ovule increases greatly in size. The integuments dry up. The outer one becomes hard or leathery and forms the outer seed coat or testa while the inner one, if persist, forms the tegmen. The nucellus is generally used up during the development of embryo but in some cases it remains outside the endosperm in the form of a thin layer, called perisperm. The endosperm may persist or completely digested during embryogenesis. A scar is usually visible on one side of the outer seed coat. It is known as hilum and marks the point of attachment to the stalk. With these changes, the ovule changes into seed and enters a period of dormancy while the ovary ripens into a fruit. Dicotyledonous seeds Exalbuminous : Gram, Pea, Bean, Mustard, Mango, Groundnut, etc. Albuminous : Castor, Poppy, Artabotrys, Custard apple (Ananas) etc. Monocotyledonous more...

Systematic position         Division      :         Angiospermae         Class            :         Dicotyledonae         Subclass     :         Gamopetalae         Series          :         Bicarpellatae         Order          :         Polimoniales         Family         :         Solanaceae 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 system. 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), more...