The others are " Hemidictyum " and " Asplenium " . " Hymenasplenium " was segregated because it is a natural grouping with differing rhizome morphology dorsiventral v . radial for the rest of Asplenium, differing chromosome count x = 39 v . x = 36 for the rest of Asplenium, and a clear monophyletic grouping based on genetic analysis.
12.
It is a medium-sized plant, growing to about 4 5 feet ( though 10 12 feet in a sheltered place at Arduaine Garden in Argyll, Scotland ) and even though the rhizome does not grow a trunk, it is clearly related to the other tree ferns due to features that were apparently already present in their common ancestor, like " " pneumathodes " ", and the rhizome which changed from the dorsiventral symmetry typical of the other ferns, to a radial symmetry typical of tree ferns.
