槐叶苹 huai ye ping

Marsilea natans Linnaeus, Sp. Pl. 2: 1099. 1753.

Floating fronds sessile or with stipe to ca. 1 mm; lamina Robinia-shaped, 0.8-1.4 × 0.5-0.8 cm, base rounded or subcordate, margin entire, apex obtuse; lateral veins 15-20 on each side of costa, each one with 5-8 low dome-shaped papillae, each with a terminal bunch of ca. 4 white setae; lamina deep green on upper surface, densely brown villous on lower surface; submersed fronds finely dissected into linear segments, covered with hairs, and acting as roots. Sporocarps 4-8, clustered at bases of submersed fronds, with sparse bunches of hairs; microsporocarps yellowish, megasporocarps brownish.

Floating on rice fields, ponds, ditches. Throughout most of China, widely distributed along the Chang Jiang [India, Thailand, Vietnam; Africa, Asia, Europe].

The whole plant is used medicinally; it is boiled and eaten for "consumptive disease" and eczema and externally used for inflammatory diseases affecting the skin.

The name Salvinia natans has been misapplied to plants in North America (S. minima Baker).