Page 26 - Lesson Notes-Morphologyof flowering plant

2. Distribution The family includes 600 genera and 13000 species. It is distributed all
over the world except the Arctic regions.
3. Habit The plants are mosdy herbs, however shrubs, trees and climbers are also
common.
4 Vegetative Characters
(i) Root Tap root with lateral branches. The lateral branches mostly contain bacterial
nodules (with Rhizobium bacteria which fix atmospheric nitrogen).
(ii) Stem Herbaceous or woody, branched, erect or climbing.
(iii) Leaf Alternate, pinnately compound or simple, leaf base, pulvinate, stipulate,
venation-reticulate.
5. Floral Characters
(i) Inflorescence Simple raceme, axillary cyme or solitary.
(ii) Flower Bracteate, pedicellate, subsessile, bisexual, mostly, irregular, zygomorphic,
sometimes regular, pentamerous, hypogynous or slightly perigynous.
(a) Calyx Sepals 5, gamosepalous, imbricate aestivation.
(b) Corolla Petal 5, polypetalous, papilionac¬eous, consisting of a posterior standard,
two later wings, two anterior ones forming a well (enclosing stamens and pistil),
vexillary aestivation.
(c) Androecium Stamens 10, usually diadelphous [(9) +1] or monadelphous,
sometimes free, polyandrous, another dithecous, basifixed (attached by its base).
(d) Gynoecium Monocarpallary, ovary superior, unilocular with marginal placentation,
style bent, stigma simple and hairy.
(e) Fruit Legume (pod).
(f) Seed One to many non-endospermic.
(iii) Floral Formula