- ≡ Doodia ×digena Parris, New Zealand J. Bot. 10: 596 (1972)
Blechnum ×digenum is believed to be the hybrid between B. molle and B. parrisiae, usually arising wherever the two parent species occur together. It is recognised by its intermediate morphology. The fertile and sterile fronds are dimorphic, unlike those in B. parrisiae. The fronds are harsh, and the rachises bear scales, unlike those in B. molle. There are 22–30 pairs of pinnae, intermediate between the range of 11–21 in B. molle and 20–50 in B. parrisiae. The pinnae at mid-lamina are stalked, rather than sessile or adnate as in B. parrisiae. Spores in some hybrid plants (e.g. WELT P017873, Wairua Falls near Whangārei, and WELT P015771, Pukemokemoke) are of very irregular sizes (but not shrivelled and aborted); others appear normal, as reported by Parris (1972).
n = >30 univalents + >60 bivalents (Brownlie 1961– as intermediates between Doodia caudata and D. media). The presence of bivalents and univalents strongly suggests that the spores would be sterile.