Hi,
I'm trying to sort a spreadsheet of fern information alphabetically, first by column A (genus) and then by column B (species). Columns C-F contain additional information.

I've selected data sorting in the order of Column A then Column B.

However, it consistently puts some items out of order for column B, making it difficult for me to check the species information. I've double checked for extra spaces, there are no extra characters. I don't understand what's happening.

Example:
Sorted alphabetically, Dryopteris marginalis will be listed before Dryopteris goldiana.

Or it will list
Dryopteris marginalis
Dryopteris marginalis
Dryopteris intermedia
Dryopteris marginalis
Dryopteris marginalis.

Can anyone help? Thank you!