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BOTANY Higher Secondary Second Year - Textbooks Online

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1.3.2. FABACEAE – the bean family<br />

Systematic position<br />

Class: Dicotyledonae<br />

Sub-class: Polypetalae<br />

Series: Calyciflorae<br />

Order: Rosales<br />

Family: Fabaceae<br />

General characters<br />

Distribution<br />

Fabaceae includes about 482 genera and more than 7,200 species.<br />

The members are cosmopolitan in distribution but abundant in tropical and<br />

subtropical regions. In India, this family is represented by about 100<br />

genera and 754 species.<br />

Habit<br />

The members of this family exhibit different habits. Prostrate herb<br />

eg. Indigofera enneaphylla (Seppu nerunji), erect herb (eg. Crotalaria<br />

verrucosa), twiner eg. Clitoria ternatea (Sangupoo), tendril climber<br />

eg. Pisum sativum (Pea plant), shrub eg. Cajanus cajan and trees<br />

eg. Pongamia glabra. Aeschynomene aspera (Pith plant) is a hydrophyte<br />

and commonly called pith plant.<br />

Root<br />

Branched tap root system having nodules. Nitrogen fixing bacterium<br />

Rhizobium leguminosarum occurs in the nodules.<br />

Stem<br />

Aerial, weak stem (eg. Clitoria ternatea) or woody (eg. Dalbergia<br />

latifolia).<br />

Leaf<br />

Simple (eg. Crotalaria juncea) or bifoliate (eg. Zornia diphylla) or<br />

trifoliate (eg. Lablab purpureus) or imparipinnately compound (eg. Clitoria<br />

ternatea), terminal leaflets modified into tendrils in Pisum sativum. Leaves<br />

are alternate, stipulate, leaflets stipellate, pulvinate showing reticulate<br />

venation.<br />

22

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