Stratiotes

Scientific name

Stratiotes L.

Common names

water soldier, water aloe, crab's claw, sahalehti

Family

Hydrocharitaceae

Could be confused with

Eriocaulon, Vallisneria

Native distribution

Europe and central Asia

Species commonly cultivated

Stratiotes aloides L. (Europe and central Asia)

Adventive distribution

information not available

Weed status

Considered a prohibited import in some states of the United States. Erroneously listed on U.S. federal noxious weeds list instead of Ottelia alismoides (corrected in 1995). Various countries have listed Stratiotes as a weed of special concern (e.g. New Zealand, Australia), although few or only brief weed infestations are recorded in its present range.

Habit

rosette plant; completely submersed or floating below water surface with emergent leaves, attached or unattached

Brief description

Perennial, submerged in winter, rising to just below water surface in warm season to flower. Stem compact and branching, branches appearing stolon-like. Leaves in a rosette, linear to lanceolate, rigid, with serrate margin. Roots unbranched and rarely reaching substrate. Inflorescence unisexual (plants dioecious); male inflorescence of 3-6 flowers; female inflorescence solitary or rarely of 2 flowers; spathe of 2 overlapping bracts. Flower actinomorphic; sepals 3, green; petals 3, showy, white. Dispersal by resting buds and seed.

Natural habitat

still or stagnant waters of lakes, ponds, and swamps

Additional comments

Stratiotes aloides is a protected species that is threatened with extinction in parts of Europe. It prefers still, nutrient-rich waters but is apparently sensitive to pollution.