Definition of "morphologically"

Although Roellobryon is morphologically similar to Rhodobryum and Rosulabryum, recent molecular studies suggest that it is closer to Mniaceae than Bryaceae.

2014, Flora of North America North of Mexico, page 186

In a typical lexicalist approach (e.g. Koontz-Garboden 2006), the unmarked lexeme is taken as lexically listed, even if its meaning (as it often does) includes templatic entailments, and the derivational morphology is taken to operate on the underived form to yield the derived form. This is the case not only morphologically, but also semantically.

2014 September 25, Rochelle Lieber, Pavol Stekauer, editors, The Oxford Handbook of Derivational Morphology‎, page 347