The first vowel of murchantia

heard as murchantia

spelled marchantia

An a: Marchantia.

What the ear did

An r behind the vowel flattens it. The surname Marchant fixes the letter.

Sound decision: an unstressed vowel blurring. Said mar-KAN-tee-uh, often mar-KAN-sha.

M-A-R-C-H-A-N-T-I-A

The full entry for marchantia covers the name itself.