I just read Ben Faber's blog post titled "Weed ID in Your Hands" from the Topics in Subtropics blog. Ben mentions,
"Who says you can't know all those wild things growing in the field you didn't put there? Here's a chance to learn what they are for cheap. UC Publications is having a book sale and they are a deal until February 14."
These are the lowest prices I've seen for these books. If you don't have these weed science books in your library or need a second copy, here's your chance to pick them up at a 25% discount. Sale ends February 14, 2020.
Weed Control in Natural Areas in the Western U.S. (Publication #3547, $25.00 $18.75)
Aquatic and Riparian Weeds of the West (Publication #3421, $40.00 $25.00)