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In this article we will discuss about:- 1. Characters of Marantaceae 2. Distribution of Marantaceae 3. Economic Importance.
Characters of Marantaceae:
Leaves 3-sectioned i.e., sheath, petiole, blade with the peculiar pulviniform ligule, unusual androecial condition with its several staminodes and solitary monothecous anther; 1-3 loculed ovary with a single apparently basal ovule in each fertile locule; the seed arillate with curved or folded embryo.
A. Vegetative characters:
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Habit:
Perennial herbs or shrubs.
Root:
Adventitious.
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Stem:
Acaulescent, rhizomatous rarely tuberous and sub-terranean.
Leaf:
alternate, petiolate, sheathing lamina usually linear, ovate, oblong or elliptic, pinnate, closely parallel, ligule or pulvinus-like swelling on the stalks; leaf distinguished into sheath, petiole and blade.
B. Floral characters:
Inflorescence:
Spikes or panicles sometimes scapose usually surrounded or subtended by a spathacous bract.
Flower:
Zygomorphic, hermaphrodite, epigynous, often in pairs at the axil of bracts.
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Perianth:
Tepals 6, in two whorls of 3 each, usually differentiated into calyx and corolla.
Sepal:
3, free and imbricate.
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Petal:
3, connate in an unequally lobed tubular corolla, the posterior corolla lobe is somewhat concave, lobes imbricate.
Androcium:
Stamens of outer whorl are represented by 1 or 2 petaloid staminodes or all the members completely suppressed; in the inner whorl the posterior median stamen as in Canna bear half anther, the other half anther lobe modified into a petaloid appendage, the remaining two lateral stamens of the inner whorl are modified into petaloid staminodes, of which one functions as a labellum and forms a hood over the stigma for time being ‘the staminode cocculatum.’
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Gynoecium:
Carpels 3, syncarpous, ovary inferior, trilocular or unilocular (2 locules being often sterile), ovules 3 or 1 due to abortion of two other ovules, axile placentation; style 1, stout, flat, and twisted, lobed, involute or apically delated, the stigma 1, terminal turncate or depressed.
Fruit:
Loculicidal capsule or fleshy and berry like but dehiscent.
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Seed:
Arillate with mealy perisperm, endospermic.
Pollination:
Entomophilous.
Floral formula:
Distribution of Marantaceae:
Marantaceae or arrow root family represented by 26 genera and 350 species, distributed in the tropics and sub-tropics, but mostly plants of moist, or swamy forest habitats.
Economic Importance of Marantaceae:
1. Food:
The bulbs of Maranta arundinacea yield ‘commercial arrowroot’ a diet for children, due to presence of readily digestible starch.
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The tubers of Calathea allouia (West Indies) are edible.
2. Mat:
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The split stems of Clinogyne dichotoma are woven into mat.
3. Ornamentals:
Thallia dealbata, Phrynium are grown as ornamentals.
Common plants of the family:
1. Maranta arundinacea – Arrow-root.
2. Thallia – a popular garden aquatic.
3. Calathea alovia – common in W. Indies.
Division of the family and chief genera:
The Marantaceae is divided into 2 tribes viz.:
Tribe I: Phryneae:
Ovary trilocular, sometimes unilocular, each chamber one ovuled. Genera: Clinogyne, Phrynium etc.
Tribe II: Marantee:
Ovary unilocular, one ovuled only. Genus: Maranta.
