Is it woodsha or woodsia?

An s followed by -ia turns into a sh sound in ordinary English speech, which is how fuchsia ended up sounding like few-sha and why woodsia can sound like wood-sha. The sh is genuinely there in the mouth. It is just never written, because the ending is not a sound at all but a piece of grammar: -ia is what botanical Latin adds to a person's name to turn it into a genus. Woods, the botanist, plus -ia, the honour. Write it woodsha and you have deleted the man.

The last syllable, where botanical Latin keeps letters that speech drops.