2010.06.30 Vienna XXII. (Lobau bayou - standing water, 152 m AMSL).Note shape of (young!) flowers: the lower lip's edges are turned down; older flowers flatten out. This is a feature distinctive for this species.German name: Gewhnlich-WasserschlauchID: Fischer & al., Exkursionsflora (2008 3rd)
Kohler's Medizinal-Pflanzen in naturgetreuen Abbildungen mit kurz erlauterndem Texte :.Gera-Untermhaus :Fr. Eugen Kohler,[1883-1914].biodiversitylibrary.org/page/303638
Found along the southern rim of the Neotropics, from Bolivia to northeastern Argentina. Known as Mini Angel's Trumpet in gardening. University of B.C. Gardens.