markansha, spelled exactly as it sounds
heard as markansha
spelled marchantia
Every sound in that is right. The letters are Marchantia.
What the ear did
The k is a ch and the sha is a tia. Neither is guessable from the sound, and both come from the same source: a French surname given a Latin ending by an eighteenth century botanist who was not worried about English readers.
M-A-R-C-H-A-N-T-I-A
The full entry for marchantia covers the name itself.