In this article we will discuss about:- 1. Characters of Aristolochiaceae 2. Distribution of Aristolochiaceae 3. Economic Importance 4. Affinities.
Characters of Aristolochiaceae:
Plants twinner, flower actinomorphic, trimerous, stamens 6-36 free or attached with the style forming gynostemium, generally 6-loculed inferior ovary.
A. Vegetative characters:
Mostly climbing herbs or shrubs with woody stems or low herbs.
Tap and branched.
Softly woody or herbaceous, branched twinner.
Simple, alternate, with oil glands, entire, petioled, exstipulate.
B. Floral characters:
Either solitary or clustered or in racemes of spikes.,
Hermaphrodite, actinomorphic or zygomorphic, epigynous and with haplochlamydous trimerous perianth usually.
In Aristolochia flowers aire zygomorphic, the perianth members are united to form a pitcher like structure having constricted neck, the interior of which is lined with downwardly directed hairs.
3 petaloid, united, 3-lobed or unilateral often bizarrely coloured occasionally an inner whorl of 3 minute teeth (vestigial corolla) present.
Stamens 6-36. free or adnate to style and producing a column or gynostemium, filaments short and thick or anthers sessile, bithecous dehiscing longitudinally.
Carpels usually 6 rarely 4, connate in an inferior six chambered, rarely four chambered ovary. Ovules anatropous, many on axile palcentas.
Septicidal capsule with basal dehiscence.
Endospermic and small.
Distribution of Aristolochiaceae:
The family Aristolochiaceae or Birthwort family contains 7 genera with 625 species (Rendle) having fairly wide range of distribution, the main centre of distribution being north temperate and tropical regions of the globe. Aristolochia is mainly tropical. According to Willis genera 5, species 300.
Economic Importance of Aristolochiaceae:
The roots of Aristolochia, serpentaria and Bragantia wallichii serve as a cure for snake-bites. The roots of Aristolochia indica are used by snake-charmers for catching snakes.
Aistolochia grandiflora, A. clematis, A. microphylla, A. gigas are ornamental plants.
Affinities of Aristolochiaceae:
Hutchinson placed the family as a terminal derivative from the Ranales via herbaceous members of Berberidaceae. It is presumed that the more or less woody climbing members of the family may have derived from the herbaceous ones.
According to Bentham and Hooker, it is most closely related to certain petaliferous families such as Menispermaceae.
Ranales → Berberidales (Menispermaceae) → Aristolochiales.
Common plant of the family:
1. Aristolochia bracteolata – a decumbent, slender perennial.
2. A. tagala – twining perennial shrub.
Division of the family and chief genera:
The Aristolochiaceae is divided into three tribes viz.:
Perennial herbs or shrubs; flowers zygomorphic, solitary or in cymes or racemes. Petals absent. Stamens in one row, united with style. Ovary inferior. Fruit a capsule e.g., Aristolochia, Euglypha and Helostylis.
Shrubs or semi shrubs, flowers actinomorphic in cymes or racemes. Petals absent. Stamens in two rows, free or united with the style. Ovary inferior, fruit a capsule e.g. Apana, Thottea.
Perennial herbs, flowers actinomorphic, solitary. Petals present or absent. Stamens in two rows, free or united at base of filaments. Ovary inferior or semi-inferior. Fruit a capsule or follicle e.g. Asarum and Saruma.