Distinct from the other variety observed this morning. Cauline leaves lanceolate rather than obovate. No red on any of the petals in this population. Not sure which variety this is.
800 Hz hi-pass filter applied on sound file to reduce wind noise. Canon PowerShot SX620 HS built-in microphone.
About 3ft tall, it was waist high on me.
This plant is located in a small population of Echinodorus cordifolius I've found before.