6. Helianthus salicifolius A. Dietrich (syn.: H. filiformis Small) (N-Am.) – An exceptional and ephemeral escape from cultivation. Recorded once, in 1952, on the borders of the Albertkanaal at Schoten (as H. tuberosus), doubtlessly gone now. Helianthus salicifolius is very characteristic by its linear to lance-linear leaves (at most 12 mm wide) and glabrous stems.
Long R.W. Jr. (1954) Helianthus salicifolius in cultivation. Baileya 2: 47-52.