Bonjour
have you try some spore sowing?
ROBBIN C MORAN to the missouri botanical garden made a very good article on potato fern.
S.brunei is find on Costa rica -Panama-Colombia -Ecuador
S.bismarckii and S. tuberosa Ecuador and Peru (1100 to 2000m)
S.brifons in amazonia lowlands of Colombia,Ecuador-Peru (200 to 800m)
microgramma and solanopteris are sister genera not the same
microgramma : "lacks tubers, has narrowly lanceolate scales on the rhizomes, smooth or wartyspores and usually lacks hairs among the sporangia "
solanopteris :"tubers,small,round scales on the rhizomes, spinyspores,and slender club-shaped hairs among the sporangia "
jeff