English: Water sprite; Indian fern; Water fern; Oriental waterfern; Water hornfern.
Philippines: Pakung-sungay, meaning antler fern or horn fern.
Synonym: Parkera thalictroides
Clades: Parkerioideae;
Pteridaceae.
Region: tropical.
Habitat: rooted in mud; near stagnant water, in still pockets, along slow flowing rivers, swampy areas, swamp forests, sago swamps, marshes, natural and man-made ponds; massed on or around logs or other floating vegetation; thrives in full sun to moderate shade; altitude up to to 1300 meters.
Under the right conditions the plants will grow fully emerse erect leaves.
Use: leaves, cooked, as a vegetable, raw as a salad, similarly to watercress; ornamental, aquarium plant, prized for its versatility, both floating and rooted; as manure for rice; medicinal for dermatitis and bleeding; leaves as personal decoration.
BotanyFern: erect; homosporous; exclusively aquatic or subaquatic; emersed to natant, or immersed, rooted in the substrate; variable size and appearance; grow fast under bright light.
Root: rhizome short, fleshy; horizontal ascending to erect; loosely rooted in the mud or floating; radial, dictyostelic with numerous meristeles and medullary strands; young parts bear thin, ovate, ± cordate, clathrate scales.
Stem: 3 to 15 mm in diameter; spongy; air-filled; 4 to 60 cm long.
Leaves: pale green, brown when matured; fertile are 15 100 cm, including the stipe, to 40 cm long; stipitate, stipes fleshy; with numerous longitudinal air canals; abaxially rounded and ribbed; adaxially flattened; vascular bundles in a peripheral ring, one with each rib and several to the adaxial side, several smaller medullary strands; lamina dimorphic; sterile fronds ± spreading, 2 to 3-pinnatifid with broad membranous lobes; venation reticulate without included free veinlets; often with proliferous buds in the axils; fertile fronds erect, longer, narrower and more divided than the sterile, lobes strongly recurved to completely cover the adiaxial surface, venation longitudinal, branching at the bases of the lobes; buds proliferous or dormant, with overlapping dark scales in the axils of fertile pinnae are winged; pinnae are deeply incised, segments 2 to 15 mm long, 10 to 30 mm wide.
Sporangia: solititary, scattered along the veins, exindusiate but protected by the continuous reflexed margin of the lamina, large, short-stalked, annulus broad, irregular; 30 to 70 thickened cells, or lacking, containing 16 to 32 spores.
Spores: large; trilete; ribbed with irregular long meshes.
Propagation: reaching maturity and shedding spores during the dry season, with loss of all sterile fronds; functionally annual, but it is of indefinite lifespan in cultivation; small adventitious plantlets are grown on the mother plant and are then released when ready.
Chromosomes count: north type 2n=126; south type its 2n=154.
TaxonomyCeratopteris was formerly placed in the monogeneric family Parkeriaceae, thought to be unique because of its aquatic adaptations. Recent genetic analysis has shown it to be allied with Acrostichum in the subfamily Parkerioideae, within the family
Pteridaceae.
Formerly only one species was recognised, later 4 species. Recent reaserach jhows that
Ceratopteris thalictroides actually consists of four species: thalictroides, froesii, gaudichaudii, oblongibloba.