Plant Family Alismataceae

Alismataceae Description General/Distribution A cosmopolitan family of 12 genera and about 90 species. Only 4 genera and 8 species are reported from West Pakistan .Detailed DescriptionAnnual or perennial, amphibious herbs with laticiferous ducts. Rhizome mostly stout, short, with adventitious fibrous root s. Leaves radical, rosetted, erect or floating with vaginate petiole, rarely floating or submerged and reduced to phyllodes, lamina linear-lanceolate to sagittate, rarely ribbon shaped or broadly elliptic to ovate, with parallel convergent venation and hydathodes. Inflorescence simple or compound, scapose, raceme or panicle with verticelled flowers and branches; peduncle mostly spongy, rarely hollow. Flowers small, bisexual or more rarely unisexual, actinomorphic, trimerous, hypogynous. Bracts 3 rarely 2 per whorl of flowers or branches. Thalamus flat to globose. Sepals 3, free, green, imbricate, persistent. Petals 3, free, mostly white rarely pink, fugacious, imbricate, rarely absent. Stamens 3-many, free, filaments flattened or filiform, anthers basifixed or rarely versatile, dithecous, dehiscing longitudinally. Carpels 3-many, whorled or spiral, apocarpous or occasionally basally connate; ovaries superior, sessile or stipitate, unilocular, each with 1, rarely 2 or more erect, campylotropous or anatropous ovules; styles terminal or ventral, stigma simple. Fruit a head (etaerio) of free achenes or rarely basally united follicles. Seeds oblong or curved, with membranous, smooth, wrinkled or ridged testa, exalbuminous; embryo curved, hippocrepiform. Identification key 1. Inflorescence with bisexual flowers only 2. Leaves broadly elliptic-ovate, cordate. Carpels mostly 6-9, rarely few or more, crowded on the thalamus. Achenes drupaceous with sclerenchymatous endocarp 2. Leaves linear-lanceolate to ovate. Carpels many in a single whorl on the thalamus. Achenes compressed, without sclerenchymatous endocarp 1. Inflorescence with both bisexual and unisexual or only unisexual flowers 3. Flowers mostly unisexual. Achenes laterally compressed, thin, winged and beaked 3. Flowers male and bisexual. Achenes turgid, beaded, neither thin nor winged but with 2 lateral air sacs between endocarp and exocarp Floral Diagram of Alismataceae

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