This is a widespread southeastern taxon of swampy woods and marshes. Full species status may be doubted, given similar range and habitats; some colls. may be hard to assign, T. walteri differs from tubulosum as follows (Y, W): styles 1.5-3 mm long (versus 0.5-1.5 mm); sepals 3-5 mm long, obtuse (versus 4-7 mm, acute to obtuse); leaves all narrowed or tapered at base (versus with upper leaves rounded to cordate), the lower leaves petiolate (versus sessile); leaves with translucent to yellowish or dark glands (versus lacking such glands).