Callitriche

Scientific name

Callitriche L.

Common names

starwort

Family

Callitrichaceae

Could be confused with

Didiplis, Micranthemum, Potamogeton

Native distribution

cosmopolitan

Species commonly cultivated

Callitriche heterophylla Pursh (North America)

C. palustris L. (North America, Europe)

C. stagnalis Scop. (North America, Europe, Asia, Australasia)

C. verna L. (North America)

Adventive distribution

Cosmopolitan distribution makes determination of new introductions difficult.

Weed status

rarely weedy in rice crops

Habit

submersed, floating, delicate stem plant

Brief description

Annual or perennial. Stems elongate when submersed or compact when emersed. Leaves opposite, decussate, in a terminal rosette when floating, sessile; leaf blade linear to oblong to spathulate, only midvein prominent; apex often (unequally) notched; margin entire. Flowers minute, solitary, axillary, unisexual; petals and sepals absent; male flower with a single stamen as an elongate filament with reniform anther; female flower with 2 elongate styles. Dispersal by stem fragments or seed.

Natural habitat

lakes, ponds, and slow flowing rivers

Additional comments

Callitriche is the sole genus in the family, comprising 17 to 35 species distributed worldwide. Some species have been used as indicators of water quality as they may be sensitive to pollutants and aggressive competition from introduced plants.