Hydrothrix and Scholleropsis, two segregate monospecific genera placed within the Heteranthera s.l. clade, are here transferred to Heteranthera based on phylogenetic and morphological data. A brief discussion on the morphology and affinities of Heteranthera s.l. is given, along with the designation of lectotypes for the two new transfers.
Fig. 1- Heteranthera gardneri
Heteranthera gardneri. A, habit, showing a flowered population during dry-season; B, detail of the stem. C, detail of the flower-like inflorescence, showing how the upper perianth-lobes mimic androecium parts. A–B by A.P. Fontana, C by C.P. Bove.
Fig. 2- Heteranthera lutea
Heteranthera lutea. A, habit, showing an individual with petiolate and sessile leaves; B, habit, showing a submerged individual with only sessile leaves; C, detail of the one-flowered inflorescence, showing the tetramerous flower. Plate modified from the Flore de Madagascar et des Comores, Pontédériacées (1946), vol. 38: pp. 5; acquired through the Biodiversity Heritage Library (BHL).
Fig. 3- Heteranthera species
Related Heteranthera species. A–B, Heteranthera dubia, from the United States: A, habit showing submerged individual with sessile and linear leaves; B, detail of the one-flowered inflorescence. C–D, Heteranthera rotundifolia, from Northeastern Brazil: C, habit, showing; D, detail of the flower; E–F, Heteranthera seubertiana, from Northeastern Brazil: E, detail of the sessile leave rosette; F, detail of the inflorescence, showing the open yellow flowers. G–H, Heteranthera zosterifolia, from Southeastern Brazil: G, habit, showing the emerged stem with sessile linear leaves; H, detail of the flower. A–B by C.N. Horn, C–D by A. Popovkin, E–F by R. Teobaldo, G by G. Oliveira and H by S.S. de Oliveira.
