ADVICE for plant resources and knowledge building!

So I was introduced to permaculture in 2011 and its literally changed my life...I'm a 25 year old male and this summer Ill be beginning an internship on an organic permaculture-style farm here in NH. I'm also taking an excellent PDC course in august up at Whole Systems Designs in VT. I understand many of the basics of permi principles,ethics, and the communal side of things as well as natural building (taken a few timber framing courses) and grew up around an auto-shop and did some side construction work, so I can really grasp the building/shelter.energy/mechanical systems...

However... PLANTS are my weak point. I'm looking for suggestions on books/pdf's/videos/study guides/ on basic plant biology, species ID, species function/properties etc. I'm really a newbie on plants from trees to annual veggies I NEED to boost my knowledge... any advice would be wonderful. Thanks!

do a search on-site for book recommendations, but would start with Botany in a Day, by Epple ?
and probobly Gaia's Garden. It is a consolidation of most of the other permie style books out there.

You will need it for identifying all the weeds and volunteers for all the rest of your studies.