Key for Echinodorus Rich. ex Engelm.

1Anthers basifixed; carpels 15-20
1'Anthers versatile; carpels more than 20
2Emersed leaves with pellucid markings absent; flowers 0.6-0.8 cm wide
2'Emersed leaves with pellucid markings present as lines; flowers 0.8-1.7 cm wide
3Fruits eglandular
3'Fruits glandular
4Pellucid markings of leaf blades present as reticulate network
4'Pellucid markings of leaf blades absent
5Leaves with basal lobes
5'Leaves without basal lobes
6Inflorescence racemose, decumbant, with 3-4 whorls, vegetatively proliferating; bracts longer than subtending pedicel
6'Inflorescence paniculate or rarely racemose, erect, with 7-14 whorls, not vegetatively proliferating; bracts shorter than subtending pedicel
7Submersed leaves usually present; glands of fruits 5 or more, circular
7'Submersed leaves absent; glands of fruits 1-2, rarely to 5, elliptic to linear-elliptic;
8Leaves with pellucid markings as separate lines; rachis usually winged between whorls; fruit beak less than half as long as fruit
8'Leaves without pellucid markings, rarely present as separate lines; rachis triangular between whorls; fruit beak half or more as long as fruit