Ceratopteris thalictroides (L.) Brongn.

Code

CESTH

Growth form

fern

Biological cycle

annual

Habitat

aquatic

Global description 

Ceratopteris thalictroides is a highly polymorphic species. It is an annual aquatic fern fixed in the substrate. The typical form is characterized by a frond deeply divided into rounded to filiform lobes. The sterile fronds have broad pinnate lobes while the fertile fronds have filiform lobes. It measures 25 to 30 cm in height. The fronds develop in clumps. The sporangia are located along the veins and protected by the reflected margin of the lamina. The spores are tetrahedral.
 
Underground system
 
The root is rhizomatous, short and erect, covered with fine and translucentscales, light brownish in color.
 
Frond
 
The frond is carried by a spongy and full of air petiole, 3 to 15 mm in diameter. It is semi-cylindrical, 3 to 30 cm long. The lamina is pale green in color, becoming brown as it grows older, soft, generally oval in shape, but deeply multi-pinnate in rounded(sterile forms)  to filiform lobes (fertile forms). The general form of the lamina is oval to lanceolate. The base is rounded or wedged and the top acuminate. The lamina is 6 to 30 cm high and 3 to 15 cm wide. The fertile fronds are larger than the sterile fronds and can measure up to 100 cm in height including 40 cm of petiole. Both faces are glabrous. The lamina of the sterile fronds is multi-pinnate (2 to 4 times divided) with 5 to 8 pairs of alternate lobes largely ovate to triangular ovate, themselves divided. The terminal lobes are much narrowed becoming filiform and decurrent along the main veins giving them a winged appearance. The fertile fronds have filiform lobes several times divided, with acuminate apex. The margin is fine, clearly reflected or recurved. The veins are anastomosed.
 
Reproductive organs
 
Spores are located on the underside of each side of the main veins and are often covered by the margins of reflected lamina. The fertile fronds become brown at the time of fruiting. The sporangia are formed from 30 to 70 annular cells containing 32 spores inside. The spores are tetrahedral, over 100 μm in diameter.
 

Ceratopteris thalictroides is an annual species. It multiplies by spores dispersed in water.

Ceratopteris thalictroides can be confused with C. pteridoides whose fronds are carried by a petiole 5 to 8 cm long and 1 to 3 cm in diameter, the lamina broadly triangular and the fertile fronds not larger than the sterile fronds.

 
Not all taxonomists agree to group or differentiate C. thalictroides from C. cornuta. The differences between these two species are not clear.

Ceratopteris cornuta can easily be confused with C. thalictroides. C. cornuta is differentiated by less divided sterile fronds and smaller fertile fronds with wider lobe tips giving a more robust appearance than C. thalictroides.

Ceratopteris thalictroides is an annual aquatic plant rooted in soil. It is widespread in all tropical regions of the globe, up to 800 m altitude. It inhabits flooded rice fields, swamps and low flow streams with temperatures between 20 and 30 ° C. It prefers soft to moderately hard and slightly acid waters.

French Guiana : Annual aquatic herbaceous plant, common on the edges of rice paddies and canals; it is sometimes found in the paddies. It can be found in vegetable crops (Bazellea alba) when soil is very moist and temporary flooded.

Worldwide Distribution

 
Ceratopteris thalictroides is a pantropical species. It is found in China, India, Indonesia, Myanmar, Nepal, New Guinea, Philippili, Sri Lanka, Thailand, Vietnam, Africa, Australia, America (North, Central and South), Madagascar, Pacific Islands and the West Indies.

French Guiana : Present but scarse in vegetable crops when soil is very  moist.
Madagascar: Weed of flooded rice fields.
South Africa : Absent.

Food: Fronds are consumed as a cooked vegetable in Madagascar, New Guinea, Vietnam. 

Aquariophylia: This species is widely used in aquariophylia.

Herbarium pictures ReCOLNAT: https://explore.recolnat.org/search/botanique/simplequery=Ceratopteris%2520thalictroides