In this article we will discuss about:- 1. Characters of Geraniaceae 2. Distribution of Geraniaceae 3. Economic Importance 4. Affinities.
Characters of Geraniaceae:
Flowers hermaphrodite, actinomorphic rarely zygomorglic, hypogynous, pentamerous, Stamens 10, obdiplostemonous; carpels 3-5, ovary terminating into beaked structure at the apex; beaked or lobed fruit distinctive by its usually elastic dehiscence.
A. Vegetative characters:
Habit:
Annual herbs or under shrubs very rarely shrubs.
Root:
Tap and branched.
Stem:
Often fleshy, thick below and woody, in many genera rhizome or tuber like covered with simple or glandular hairs.
Leaf:
Alternate or opposite rarely, leaves incised or palmilobed or incised upto the base or compound, rarely entire, stipulate.
B. Floral characters:
Inflorescence:
Cymose or solitary or biclustered.
Flower:
Hermaphrodite, actinomorphic, rarely zygomorphic, hypogynous, bracteate, pentamerous, complete.
Calyx:
Sepals 5, rarely 4 or 8, polysepalous, rarely connate, partially imbricate, rarely twisted, the posterior sometimes spurred.
Corolla:
Petals 5, rarely 4 or 8, imbtricate nectiferous glands usually alternating with the petals, polypetalous.
Androecium:
Stamens 10 in two whorls of 5 each, obdiplostemonous, outer stamens, shorter than inner rarely stamens 15 in 3 whorls, sometimes stamens reduced to antherless or scale-like staminodes, sometimes basally connate; anthers, basifixed, bithecous, pendulous with special connectives.
Gynoecium:
Carpels 3-5 rarely 2-3, syncarpous. Superior, 3-5-carpellary, axile placentation, ovules 1-2 in each locule, pendulous, anatropous; style 3-5, slender (beak-like) ovary terminating into beaked structure at the apex, stigma ligulate, (rarely capitate).
Fruit:
Capsule, dehiscing septicidally into 3-5 rarely more, one or more seeded beaked parts or mericarps, the style usually adhering to the ovarian beak and the basal portion recurving elastically and sometimes spirally.
Seed:
Plicate cotyledons, incumbent, embryo mostly curved, without endosperm or endosperm scanty.
Pollination:
Entomophilous.
Floral formula:
Distribution of Geraniaceae:
Geraniaceae of 11 genera and 650 species widely distributed over temperate and subtropical regions of northern and southern hemispheres.
Economic Importance of Geraniaceae:
1. Oil:
Aromatic oil-French rose oil or otto is obtained from Pelargonium odoratissimum Ait.
2. Ornamental:
Different species and hybrids of Geranium and Pelargonium are cultivated in gardens for their showy and aromatic flowers.
Affinities of Geraniaceae:
Geraniaceae closely resembles Oxalidaceae in both floral and anatomical structures, hence Oxalidaceae was included in Geraniceae by Hooker.
Common plants of the family:
1. Geranium ocellatum Jacq. found in hills, a straggling herb with rose-coloured flowers.
2. Erodium cicutarium- esteemed as a range-forage plant.
3. Pelargonium odoratissimum – yield on distillation, “geranium oil”.
Division of the family:
The family Geraniaceae is divided into two tribes as follows:
Tribe I: Geranieae:
Mature fruits with elastic rolled bristles.
Tribe II: Biebersteineae:
Mature fruits without elastic rolled bristies.