Author:
Qjure
Book:
Qjurious
Type:
Info
Chapter:
3-442.14.01
Ceratopteris thalictroides
English: Water sprite.
Synonym: Parkera thalictroides
Clades: Parkerioideae; Pteridaceae.
Habitat: humid tropics.
Under the right conditions the plants will grow fully emerse erect leaves.
Use: popular aquarium plant; as a vegetable in Asia; well-characterized phenotypes in genomic studies.
Botany
Fern: erect; homosporous; exclusively aquatic or subaquatic; emersed to natant, or immersed, rooted in the substrate; moderate size; 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.
Leaves: 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.
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.
Taxonomy
Ceratopteris 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.