Salvinia x molesta

Salviniaceae

Salvinia x molesta D.S.Mitch.

Link to Australian Plant Name Index for publication details and synonyms: https://id.biodiversity.org.au/name/apni/60722

Plants 5–20 cm long, often forming thick mats; rhizome to 1.2 mm thick. Foliar leaves simple, shortly petiolate, elliptical, obovate or ±round, often deeply cordate at base, 7–30 (–40) mm long, 7–20 (–25) mm wide, pale green to greenish-brown, frequently overlapping and folded along midrib; margins slightly darker, entire, often incurved; apex obtuse, notched; upper surface with elongate papillae; each papilla with 4 stiff, green hairs, incurved and connate at the tips. Submerged leaf 1–20 (–30) cm long, with brown, appressed hairs. Plants heterosporous but usually sterile; sporogenous plants with numerous, spherical or ovoid, minutely hairy, 2–3 mm long microsporocarps in 2 rows along lobes of submerged leaf and 2–3 megasporocarps at the base of fertile leaf segments. Spores, when produced, deformed and not viable. 

Introduced from the Neotropics and widespread in tropical and subtropical Australia. Usually in man-made waterbodies.

Aquatic, usually in man-made, slow-moving water-bodies.

This species was relatively recently discovered and is thought to be of hybrid origin. Commonly reproduces vegetatively, sporocarps may be formed but the spores are deformed. Probably sterile.