In this article we will discuss about:- 1. Characters of Lythraceae 2. Distribution of Lythraceae 3. Economic Importance 4. Affinities.
Characters of Lythraceae:
Branches often 4-angled, leaves of posite or verticillate, entire; presence of hypanthium, flowers actinomorphic, hermaphrodite and perigynous; sepals and petals 4, 6 or 8, corolla crumpled, free; stamens free in two whorls, usually twice the number of petals. Carpels 2-6, syncarpus, superior or semi-inferior, 2-6 celled; seed non-endospermic.
A. Vegetative characters:
Habit:
Herbs, Shrubs or trees, rarely spinecent as in Lawsonia spp.
Root:
Tap and branched.
Stem:
Herbaceous or woody, branched, branches often 4-angled.
Leaf:
Simple, usually opposite or verticillate, entire, exstipulate, or minute stipulate.
B. Floral characters:
Inflorescence:
Solitary, usually raccmose or panicles or cymes.
Flower:
Actinomorphic, hermaphrodite, perigynous, substanded by epicalyx like united pair of bracteoles.
Calyx:
Sepals 4-6 or 8, valvate, polysepalous.
Corolla:
Petals 4-6 or 8, polypetatous, crumpled in bud, sometimes absent (as in Peplis or Rotala) seeming distinct and arising from rim or upper inner surface of hypanthium, alternate with sepals.
Androecium:
Stamens 4, 8 or more or 1, usually twice as many as petals, in two whorls, the flament usually unequal in length; anthers bitheeous, introrse, dorsifixed, dehiscing longitudinally.
Gyneocium:
Carpels 2-6, syncorpous, superior or semi-inferor, 2-6 celled, axile placentation, style simple, stigma capitate.
Fruit:
Capsule.
Seed:
Embryo straight, non-endospermic.
Pollination:
Entomophilous, Cleistogamous flower in Rotula and Ammania etc.
Loral formula:
Distribution of Lythraceae:
Lythraceae or Lawsonia family comprises of 2-3 genera and 475 species. The members are widely distributed but most abundant in tropical and sub-tropical regions.
Economic Importance of Lythraceae:
1. Timber:
A few plants produce useful timber, e.g., Dauebanga Sonneratioides, Lagerstroemia parviflora, L. speciosa, L. Lanceolata, Physocalymma scaberrium.
2. Dye:
The red-dye, henna is prepared from leaves of Lawsonia innermis L, The hair-dye is also prepared from its leaves. The dye is also used in dyeing hands, feet and bear.
3. Flavour:
A liquid called ‘Keora water’ – a flavouring agent is obtained from Sonneratia caseolaris by distillation.
4. Ornamental:
Some species of Lagerstroemia indica, Cuphea platycentra, Lawsonia, Lythrum salicaria etc., are cultivated as garden ornamentals.
Affinities of Lythraceae:
The family is allied to Onagrceae.
The genus Punica (P. granatum L., the pomegranate plant) has been shifted to separate unigenic Family Punicaceae next to Lythraceae; Similarly the genera Sonnertia and Duabanga formely treated as members of Lythraceae by Bentham & Hooker have been placed in separate family Sonnertiaceae very near to Lythraceae.
Common plants of the family:
1. Ammannia baccifera L. – a marshy herb.
2. Cuphea platycentra – shrub, cultivated in the green houses for its Cigar-shaped and odd flowers.
3. Lawsonia innermis – (henna, H. Mehndi) – cultivated as hedge plant.
4. Lagerstroemia – a way-side tree.
5. Sonnertia apetala, S. acida – Occur in Sunderbans – Bengal.