Persicaria
Tutin, T.G., Burges, N.A., Chater, A.O., Edmondson, J.R., Heywood, V.H., Moore, D.M., Valentine, D.H., Walters, S.M. & Webb, D.A. 1993: Flora Europaea 1, ed. 2 but modified and names used differing
| 1 | Ochreae and petioles densely hairy |
| 1' | Ochreae and petioles glabrous or sparsely hairy |
| 2 | Spikes lax and slender, with each flower distinctly visible; ochreae strongly ciliate |
| 2' | Spikes dense and stout, with the flowers crowded and overlapping; ochreae entire or shortly ciliate |
| 3 | Peduncles with numerous subsessile yellow glands; surface of ochrea glabrous |
| 3' | Peduncles without glands; surface of ochrea with scattered hairs |
