markansia, corrected
heard as markansia
spelled marchantia
Marchantia. A ch for the k sound, a t for the s sound.
What the ear did
The ending -tia has said sha or sia in English since the Middle Ages, which is why we have militia, patient and initial. The t is doing the work of an s and looks nothing like it.
M-A-R-C-H-A-N-T-I-A
The full entry for marchantia covers the name itself.