In Hsua deflexa, the main axis was creeping with the lateral axes at right angles from it.

[1] Hsua robusta is very well preserved in cherts and as compression fossils in the Xujiachong Formation, Yunnan, China.

Hsua deflexa comes from the same formation,[1] which is Early Devonian (~Pragian to Emsian, around 410 to 390 million years ago).

The terminal sporangia of Hsua robusta placed it in the traditional family Cooksoniaceae (order Rhyniales).

[3] Hao and Xue in 2013 regarded Hsua as a "renalioid", part of the Rhyniopsida.