1. Rachis remains stout and linear, the costae branching off at regular angles of about 45 degrees. The pinnules are strongly revolute over about half the surface, appearing rolled. The branching pattern looks like this .....Argyrochosma limitanea subsp. mexicana. | ||||||||||
1. Rachis bends easily and may angle away from the costae at the takeoff points especially distally, becoming hard to distinguish from costae more distally on the frond. The hydrated pinnules not revolute over most of the surface, appearing flat. The branching pattern looks more like this .....Argyrochosma fendleri. |