Ceratopteris thalictroides thalictroides

Description

The species Ceratopteris thalictroides is a fern species belonging to the genus Ceratopteris, one of only two genera of the Ceratopteridoideae subfamily of the family Pteridaceae. 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. Recent chromosome counts have shown that the north type and the third type both have chromosome counts of 2n=156, while the south type has a count of 2n=154, making it definitely a separate species.