Salvinia

Scientific name

Salvinia Ség.

Common names

water fern, water spangles

Family

Salviniaceae

Similar genera

Phyllanthus

Native distribution

tropical Asia and South America

Species cultivated

Salvinia auriculata Aubl.

S. cucullata Roxb.

S. minima Baker

S. molesta D.S. Mitch. [synonym of S. adnata Desv.]

S. natans (L.) All.

S. oblongifolia Martius

S. rotundifolia Willd. [synonym of S. auriculata Aubl.]

U.S. Federal Noxious Weed: Salvinia auriculata complex

Identification: Salvinia auriculata complex is a group of closely related neotropical species that is distinguished by the shared feature of eggbeater type hairs. The members include S. auriculata Aubl., S. biloba Raddi, S. herzogii de la Sota, and S. molesta. Although subtle vegetativevegetative:
(adj) (1) pertaining to or to the growth of plant organs or plant parts that have nonreproductive functions, such as leaves, roots, stems, etc.; (2) concering non sexual propagules such as tubers, turions, stem fragments, root crowns, rhizomes
differences have been found among members of this complex, sporocarps are generally needed to tell the species apart.

See Salvinia auriculata complex disseminule fact sheet.

Adventive distribution

almost cosmopolitancosmopolitan:
(adj) essentially worldwide in distribution
through introductions of various species

Weed status

Salvinia are very serious environmental weeds. Salvinia molesta D. S. Mitch. is considered one of the world's most troublesome aquatic weeds. Members of the Salvinia auriculata complex are aquatic weeds on the U.S. federal noxious weed list.

Habit

free-floating, often forming thick mats

Brief description

Perennial perennial:
(adj) (of a plant) having a life cycle of more than two years
water fern. Stem horizontal, floating, irregularly forked, lacking true roots. Leaves in whorls of 3, appearing paired; 2 leaves floating and photosynthetic, orbicularorbicular:
(adj) circular in outline
to oblongoblong:
(adj) two to four times longer than wide, with +/- parallel sides
, covered with complex, unwettable hairs (open or closed at tips) on adaxialadaxial:
(adj) pertaining to the side facing toward the axis, as in the upper surface of a leaf
surface; third leaf hanging down below water surface, filamentous, resembling roots, not photosynthetic. Sporocarps borne on modified segments of submergedsubmerged:
(adj) (syn. submersed) under water; submerged below the water surface
leaves, as chains, hanging clusters or rows. Prothalli develop inside floating spores. Dispersal commonly by stem fragments.

Natural habitat

common in still waters in tropical regions

Additional comments

Salvinia is a genus of 10 species. Fronds appear to be paired, but are actually whorledwhorled:
(n) bearing whorls; a type of leaf arrangement (phyllotaxis) in which leaves are in whorls
. Two floating leaves are ovoidovoid:
(adj) egg-shaped in three dimensions
and photosynthetic while a third leaf is root-like and hangs below in the water column. Sporocarps are produced as a hanging cluster or in rows in the water column. Identification of members of the S. auriculata complex is based on the presence of 'bird-cage' or 'baby-rattle' shaped hairs on the upper surface of floating leaves. Other Salvinia species have the terminalterminal:
(adj) at the apex
hairs (or papillae) separated at the apexapex:
(n) the point farthest from the point of attachment; the tip (often pointed)
. Growth rates and biomass production are influenced greatly by nutrient levels in the water column. Salvinia minima Baker is considered vulnerable in New York (United States).