Ceratopteris thalictroides
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The species Ceratopteris thalictroides is a fern species belonging to the genus Ceratopteris, the sole genus of the Parkeriaceae family.
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[edit] Common Names
It is commonly known as water sprite, Indian fern, water fern, Oriental waterfern, and water hornfern.
[edit] Distribution
Pan-tropical. Widespread. There are three general types, known as the north type, the south type, and the third type.
[edit] Description
Plants usually rooted in mud, very variable in size and appearance, scales on rhizome peltate, thin , translucent, pale brown, (under a lens clear with dark cell walls) stipes 3 - 15 mm diameter in mature plants, spongy and air filled, sterile fronds pale green, thin, flaccid and spreading, 4 - 60 cm long, including a stipe c. half this length, fertile fronds pale green, to brown when over mature, firm, held erect, 15 - 100 cm or more long, including stipe to 40 cm long, proliferous or dormant buds with overlapping dark scales sometimes present in the axils of fertile pinnae (twice seen), sterile axes obviously winged, pinnae basically broad-ovate or deltoid with a few blunt lobes, sometimes more deeply incised, the segments 2 - 15 x 10 - 30 mm, fertile segments linear, 1 - 2 x 10 - 80 mm. [1]
Recent chromosome counts have shown that the north type and the third type both have chromosome counts of 2n=136, while the south type has a count of 2n=134, making it definitely a separate species.
[edit] Ecology
Swampy areas, swamp forests, sago (Metroxylon) swamps, marshes, natural and mand-made ponds, mostly in stagnant water bodies or in still pockets along slow flowing rivers, full sun to moderate shade, from sea level to 1300 m, but mostly less than 500 m altitude. Sometimes massed on or around logs or other floating vegetation, once recorded in a fresh-water mangrove (Sonneratia) growing amoun the finger-like pneumatophores. In some areas Ceratopteris exhibits a degree of seasonality, reaching maturity and shedding spores during the dry season; plants have lost nearly all sterile fronds by this stage. [2] The species has been reported to functionally be an annual, repopulating from spore the next season, but it is clearly of indefinite lifespan in cultivation.
[edit] Uses
It is eaten as a vegetable in Madagascar.[3]
In some areas (Sepik, Northern Province) the fronds of this species are cooked as a green vegetable. In Micronesia it is eaten as a salad. However, it is now known that the plant is carcinogenic.[citation needed]
In the Sepik it is used as a personal decoration.
[edit] Cultivation
It grows best in soil with a pH reading of 5-9 and in very high amounts of light. It usually grows quickly.
Ceratopteris thalictroides can benefit well (like all aquatic plants) from the addition of CO2. The plants reproductive technique is similar to other ferns; small plantlets are grown on the mother plant and are then released when ready.
It can provide useful shade to shyer fish and small fry. The dense roots are said to take nutrients out of the water helping to prevent the growth of algae.
[edit] References
see also Ceratopteris
