Callitriche antarctica, Engelm. ex Hegelmaier, 1867

Lansdown, Richard V. & Hassemer, Gustavo, 2021, The genus Callitriche (Plantaginaceae: Callitricheae) in South America, Phytotaxa 501 (1), pp. 85-118 : 114

6. Bracts lacking or verY occasionallY minute (<0.1 mm) and fugacious; leaves somewhat fleshY the broad connate base forming a cup, the lower reduced to scales ................................................................................................................................. 2. C. antarctica

- Bracts tYpicallY caducous but in shoot apices <1 mm long; leaves not fleshY, connate at base but not forming a cup, the lower not significantly different to the upper .....................................................................................................................................................7

7. Fruit usuallY <1 mm high and wide (occasionallY up to 1.2 mm); fruit blackish or rich orange when mature; filament 3.6–3.8 mm long.....................................................................................................................................................................................................8

- Fruits ≥ 1 mm high and wide; fruit brown, greY-brown or maroon; filament either <1.5 mm or> 4 mm long ...............................9