Classification of Horticultural Plants

Diversity in living things exists in nature and subtle differences are present even in clones. The orderly grouping of plants based on their resemblance is called classification. Like other individuals grouping and naming of plants started since primitive era based on their different uses in different cultures of the world. The horticultural plants can be classified into different groups as under:
1.   Natural classification: The natural classification is based on the
uses of the plants subsequently the name of the same plants varies in the different culture of the world according to their uses. The natural classification is not based on scientific principles; therefore, it is neither universally applicable nor acceptable.
2.   Scientific system of classification:
The modern system of classification of living organisms was proposed by R.H. Whittakar in 1969 in which all living organisms have been classified into five kingdoms viz. Monera (all prokaryotes), Protista (unicellular eukaryotes), Plantae ( multicellular and chlorophyllous eukaryotes), Fungi (multicellular and non-chlorophyllous eukaryotes) and Animalia ( multicellular and ingestive eukaryotes). The kingdom Plantae to which horticultural plants belong further classified into two subkingdoms- Phanerogamae (flowering and seed bearing plants) and Cryptogamae (non-flowering and non-seed bearing plants). A horticultural plants can be classified from kingdom to variety based on resemblance of characteristics. For example mango can be classified as under:
Kingdom                     :           Plantae
Subkingdom                :           Phanerogamae (flowering and seed bearing)
Division                       :           Spermatophyta (distinct stem, root and leaves)
Subdivision                 :           Angiosperms (true flower, seeds enclosed within fruits)
Class                            :           Dicotyledones
Order                           :           Sapindales
Family                         :           Anacardiaceae
Genus                          :           Mangifera
Species                        :           indica
Variety                         :          Amarpali
      This system of classification is based on the scientific principles and universally adopted and applicable. Pyrame de Candole first introduced term taxonomy which deals with classification and naming of plants on scientific principles whereas Carolus Linnaeus introduced binomial nomenclature system in which given plant’s name consists of two parts. The first part represents genus and second species plant belonging for example the scientific name of mango is Mangifera indica , the Mangifera being the genus and indica denoting the species. Genus (genera-plural) is the subordinate unit of the family.
3.   Classification based on life cycle:
 The plants are classified into three classes based on the period require for completing their life cycle. These classes are as follows:
 a.Annuals: The plants completing their life cycle in one growing season or in one year are called annuals. For example: zinnia, marigold and phlox. Annuals are further classified as follows:
i)                 Rainy season annuals: The annuals which are sown in May and June and flower during rainy season are called rainy season annuals. For example: Mary gold, Aster, Salvia and Zinnia.
ii)              Winter season annuals: These annuals are cultivated to bloom in winter season. The seeds winter season annuals are sown in September and October. For example: Phlox and Antirrithium.
iii)          Summer season annuals: These annuals are sown in January and February and they bloom or express their beauty during summer season. For example: Sunflower and Zinnia.
b.Biennials: The plants require two growing seasons or two years to complete their life cycle are called biennials. For example: Sugar beet, onion and cabbage. Normally biennials complete vegetative growth in first growing season followed by flowering and death in the second growing season.
c.Perennials: The plants grow year after year once planted are called perennials. For example: Rose, Tuberose and Chrysanthemum.
d.Monocarps: The Monocarps are those plants which grow and remain in vegetative phase many years and flower only once in life time thereafter they die. The new plants arise from the roots only after the death of the monocarps. For example: Agave spp.
4.   Classification based on leaves shedding:
Some plants shed few leaves while others shed all leaves once in a year. The plants are grouped into two following groups on the basis of its leaves shedding behaviour:
a.Evergreen plants: Evergreen plants are those plants which maintain green leaves through the year and shed few senescence leaves. For example: Citrus, Mango, Jackfruit, Papaya, Coconut and Banana.
b.Deciduous plants: Deciduous plants are those plants which sheds all leaves once in a year. The shedding of leaves may takes place either in dry or cold season. For example: Ber and Aonla shed their leaves in dry season and Phalsa, Apple, Pear and Peach in cold season.  
5.   Classification based on climatic requirements: A plant species can not grow, flower and fruit at all places because of climatic changes from place to place. The climate particularly temperature is most important factor affecting the growth and productivity of horticultural plants. Based on their climatic requirements the horticultural crops are classified into three classes:
a. Temperate crops: Temperate horticultural crops flourish well in temperate regions of the world. These plants can with stand with cold and needs chilling temperature. They go under rest or dormancy and sheds their all leaves during winter for examples: Apple, Pear, Walnut, Almond, Cherry, Strawberry, Plums and Peaches.

b.Tropical crops: These plants need warm and humid climate with very mild winter. The plants can not withstand with cold and can get frost injury if exposed to low temperature for example: Pineapple, Banana, Papaya, Coconut, Cocoa, Guava, Sapota and Mangosteen.
c.Subtropical crops: These plants require warm and humid climate and can tolerate low temperature during mild winter for example: Mango, Litchi, Citrus, Grape, Pomegranate, Avocado and Loquat.
    6. Classification based on season:
Horticultural crops can also be classified into three classes on the basis of the season in which they grow best:
1.   Kharif crops: These horticultural crops are sown with onset of monsoon in June –July and become ready to harvest in rainy season for example: Bhindi, Chilli, Snakeguard, Pumpkin and Sponge gourd.
2.   Rabi crops: The rabi crops are sown with onset of winter in October–November for example: Potato, Cabbage, Cauliflower, Tomato, Radish, Carrot and Pea.
3.   Zaid crops: These crops are sown in February-March for example:  Brinjal, Bitter gourd, Watermelon, Muskmelon and Pumpkin.
7.   Classification based on kinds of stem:
1.Herbs: The plants with soft and non-woody stem are classified as herbs. The herbs live year after year is called herbaceous perennials whereas herbaceous annuals complete their life cycle within one growing seasons. The examples of herbs are: annual bedding plants, vegetables, Aster, Gerbera, Balsam, Phlox and Zinnia.
2.Shrubs: The shrubs are perennial plants having many woody branches arising from the base of the plants at ground level. The shrubs are usually smaller than tree and have no main trunk. The shrubs are grown for aesthetic purpose in ornamental horticulture. For examples: Karonda (Carissa carandas L.) Phalse (Grewia subnequalis D.C.), Citrus limonia var. variegate, Jasmines, Duranta plumieri, Crotons, Acalyphas, Jatropha pandurifolia, J. rosea, Hibiscus and  Bougainvillea.
3.Tree: The plants have main trunk with woody branches arising from upper part of the trunk are called trees for examples: Mango, Aonla, Gulmohar, Jamun etc.
8.   Classification based on growth forms of the stem:
1. Erect: The plants able to grow upright at 900 angle to the ground level without artificial support are classified under erect. Examples: trees
2. Decumbent : The plants extremely inclined with the tips raised for example: peanut
3.Creeper: The plants grow horizontally and crawl on the ground with adventitious roots are called creeper. The adventitious roots arise from the nodes of the stem called stolon. Example: Strawberry.
4.Climbers: The climbers are plants which possesses special structures to climb over a support. These special structures may be look-like thorns (Bougainvillea), tendrils (Bignonia), rootlets (Ficus repens). Other examples are: Pea, Sweet Potato, money plants and Cucurbits.
9.   Classification based on uses:   
1.   Edible plants: If the plants or their parts are eaten they are called edible plants. The edible plants are further classified into:
a)   Fruits: The fruit is botanically mature ovary. The fruits are those plants of which fruits or its closely related structures (e.g. thalamus in pome) are edible for examples: Mango, Banana, Ber , Grapes and Apple.
b)  Vegetables: The herbaceous plants of which some parts are eaten either cooked or raw with the meal are termed as vegetables for examples: tomato, brinjal, peas, carrot, spinach and cauliflower.
c)   Spices: The plants or its product which are used as food adjuncts to add flavor and aroma are called spices whereas spices which are used as food adjuncts to add taste only are called condiments. Examples: Turmeric, Ginger, Black Pepper, Fenugreek, Fennel, Cumin and Coriander.
2.Ornamental plants: The plants cultivated for beautification or aesthetic values are called ornamental plants. The ornamental plants may be flowering or non-flowering. Example: Rose, Gulmohar, Zinnia, Duranta, Begonia, crotons and Acalyphas.
3.Medicinal and aeromatic plants: The plants have medicinal and aeromatic properties are classified under medicinal and aeromatic plants for example: Jasmine, Safedmusli, tulsi, Kalmegh and Mentha.
10.    Other classification:
1-Tree fruit: The fruits born on tree are called tree fruits for examples: Mango, Apple, Pear and Aonla.
2-Small fruits: The fruits born on herbs, bushes and shrubs are termed as small fruits. The examples are  Karonda, Phalsa, Raspberry, Cranberry and Strawberry.
3-Nuts: The fruits covered with hard shell separable from the firm inner kernel are called nuts or nut fruits. Examples: Cashew nut, Walnut, Pecan nut, Chestnut and Hazelnut.
Classification of Vegetables