Interesting; for Cook perhaps not "aquatic enough". It's surely difficult to draw the line between aquatic and non-aquatic. Maybe some Staurogyne species are rheophytes. On the picture of the habitat of Staurogyne sp. on the Tropica homepage inflorescences of Podostemaceae are visible, too.nearly all of the specimens of smaller species I've seen have them as coming from stream banks and seasonally flooded areas.