Persicaria sect. Rubrivena
Pl. Syst. Evol. 186: 112. 1993.
Stems erect, branched distally, unarmed. Leaves: ocrea chartaceous or coriaceous proximally and chartaceous distally, margins eciliate; petiole not winged, not auriculate; blade without dark triangular or lunate blotch adaxially, lanceolate to elliptic-lanceolate, base cordate to truncate, margins entire. Inflorescences mostly terminal, sometimes also axillary, paniclelike, interrupted. Flowers heterostylous, articulation not swollen; perianth rotate; tepals 5, connate less than 1/5 their length; stamens 8; styles deciduous, 3, included, spreading.
Distribution
Introduced; Asia.
Discussion
Species 2 (1 in the flora).
The status of sect. Rubrivena has been controversial; its members have been included in six different genera. Herbarium specimens often are identified as Polygonum polystachyum or Aconogonon polystachyum. Hong S. P. (1993) cited morphological and anatomical evidence for including Rubrivena in Persicaria as sister to sect. Cephalophilon, also noting pollen and inflorescence characters that distinguish it from Aconogonon.