Fabaceae (Papilionaceae) – Lathyrus odoratus

Fabaceae (Papilionaceae)

The members of the family are distributed in plains and hilly areas of temperate regions of both northern and southern hemisphere. Most of the plants are herbs and flower during winter. Most members are cultivated for their economic value as they are source of pulses, fodder, etc. The family comprises of 375 genera

Distinguish Features:

Herb, shrubs or tree, alternate leaves, compound leaflets are modified into tendrils, stipulated, flower hermaphrodite, zygomorphic, perigynous, calyx 5 united, corolla has papilionaceous shape, stamen ten in number diadelphous, ovary is with single carpal, fruit is a pod.

The representative species is Lathyrus odoratus (sweet pea).

Lathyrus odoratus (sweet pea):

Lathyrusodoratus (Sweet pea) Flower & Leafs

Lathyrusodoratus (Sweet pea) Flower & Leafs

Habit:

Climbing herb, cultivated as ornamental plant.

Root:

Tap root, branched, root nodulated.

Stem:

Herbaceous, weak, hallow, branched, winged, climbing.

Leaf:

Ramal and cauline, petiolate, petiole, winged, stipulate, stipules, folliaceous, imparipinnately compound, upper leaf let modified into tendril.

Lathyrus odoratus (Sweet pea) Leaf Diagram

Lathyrus odoratus (Sweet pea) Leaf Diagram

Leaflets:

Sessile, opposite, reticulate unicostate, oval, entire, acute.

Inflorescence:

Solitary axillary or pendunculate raceme.

Flower:

Bracteate, pedicellate, complete, bisexual, irregular, zygomorphic, slightly perigynous.

Sweet Pea (Lathyrus odoratus) Flower

Sweet Pea (Lathyrus odoratus) Flower

Calyx:

5 sepals, gamosepalous, campanulate, green, hairy, inferior.

Corolla:

5 petals, polypetalous, Papilionaceous: a large posterior standard or vexillum, two small lateral ones forming wings of alae, the two anterior ones united to form keel or carina, imbricate, inferior.

Androecium:

Ten stamens, diadelphous: nine stamens united to form a tube around the ovary, the 10th posterior stamens free, anthers basifixed, introse, enclose in keel.

Gynoecium:

Monocaepellary, ovary unilocular with numerous ovules and superior, placentation marginal, ovule numerous, Style slightly hairy and bent towards the posterior side of the flower, stigma terminal.

Floral Formula: K (5) C1+2+(2) A (9)+1 G_1

Lathyrus odoratus (Sweet pea) Floral Diagram

Lathyrus odoratus (Sweet pea) Floral Diagram

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