Root absent, leaves globose to ellipsoid, veinless, less than 2 mm long. Rare
Wolffia globosa (Roxb.) Hartog & Plas
Figure P8A. In this photo, the larger fronds are Spirodela polyrrhiza (see Fig. P8C, below). Wolfia plants are the small ellipsoid objects covering the water surface between the Spirodela fronds.
Root sheath winged at base; root tip sharply pointed; roots not longer than 3 cm. No red color present on fronds
Lemna aequinoctialis Welw.
87b
Root sheath not winged; root tip mostly rounded; roots often longer than 3 cm. Fronds often red colored on lower surface or with red spots on either surface
Fronds 1 to 1.5 times as long as broad, with 7-16 (21) veins. Roots 7 to 21, up to 4 cm long. { Underside of fronds often deep magenta (reddish purple) in color
Spirodela polyrrhiza (L.) Schleid.
Figure P8C. Spirodela polyrrhiza: note dark magenta color on the undersides of the several leaves turned over in the photo.
88b
Fronds 1.5 to 2 times as long as wide, with 3 to 7 veins. Roots (1) 2 to 7 (12), up to 7 cm long. { Underside and upper margins of fronds reddish in color
Figure P8A. In this photo, the larger fronds are Spirodela polyrrhiza (see Fig. P8C, below). Wolfia plants are the small ellipsoid objects covering the water surface between the Spirodela fronds.
