If you would like to read an interesting article on the Xyris of the Continental US and Canada from 1966 I can suggest this one: Kral, Robert. 1966. Xyris (Xyridaceae) of the continental United States and Canada. SIDA 2(3): 177–260. You can read it for free on the JSTOR.org website,
https://www.jstor.org/ The general public can register for 100 articles per month for free. Your "role" will be an "Independent researcher" You do not need to fill in a University. For Primary Area of Study, I used the pull down menu and clicked "Botany and Plant Sciences"
