Plants 2–120 cm. Stems 1–10 mm diam., sparsely scaly. Leaves erect. Proximal leaves broad, simple and lobed to 4-pinnate, glabrous; distal leaves finely dissected with linear ultimate segments. Sporangia nearly sessile, usually densely packed, globose. Spores tetrahedral.

Distribution

Tropical, subtropical, and warm temperate regions worldwide.

Discussion

Species 3–4 (3 in the flora).

Selected References

DeVol, C. E. 1957. The geographical distribution of Ceratopteris pteridoides. Amer. Fern J. 47: 67--72.

Hickok, L. G. and E. J. Klekowski Jr. 1974. Inchoate speciation in Ceratopteris: An analysis of the synthesized hybrid C. richardii × C. pteridoides. Evolution 28: 439--446.

Hickok, L. G. 1977. Cytological relationships between three diploid species of the fern genus Ceratopteris Brongn. Canad. J. Bot. 55: 1660--1667.

Lower Taxa

Ceratopteris pteridoides, Ceratopteris richardii, Ceratopteris thalictroides

Key

1	Sterile leaves simple, palmately or pinnately lobed, sometimes 2–4-pinnate, deltate to cordate to ovate; proximal pinnae or veins of lobes usually opposite; petioles frequently inflated. Fertile leaves usually deltate to cordate to reniform; sporangia lacking annulus or annulus well developed, indurate cells 0–10(–40).	Ceratopteris pteridoides
1	Sterile leaves (1–)2–3-pinnate, lanceolate, lance-ovate, ovate to deltate; proximal pinnae usually alternate; petioles usually not inflated. Fertile leaves lanceolate, sometimes ovate, deltate, or cordate; sporangia with well-developed annulus, indurate cells 13–71.	> 2
2	Sporangia with 32 spores.	Ceratopteris thalictroides
2	Sporangia with 16 spores.	Ceratopteris richardii