can anyone identify the chandelier?

And what about those chairs? They are incredibly cool!

I don't know about that one in particular, but the Missouri Botanical Garden Press is a good place to start:
http://www.mbgpress.info/index.php?task=rbps

The Biodiversity Heritage Library is digitizing old books, including lots of nice illustrations. I'm pretty sure you can buy them? Or at least get a 300 dpi image for printing yourself?
http://www.biodiversitylibrary.org/

Defintely all over eBay:
http://shop.ebay.com/?_from=R40&_trksid=m570&_nkw=botanical+chart

On etsy Frenchpowder by metroart, has many charts available, see blog http://vintagecharts.blogspot.com/

I have several Dr. Auzoux charts in my inventory. They are chalk plates with a black background and colorful designs. Absolutely gorgeous.
http://windsorplaceantiques.typepad.com/windsor-place-antiques-and-ephemera/2011/01/dr-auzoux-chalk-plates.html

There are a ton of them on One Kings Lane right now - I bought one from them a few months ago and I'm obsessed (had no idea how trendy they're getting). It looks like Katrien Van der Schueren is a big collector: https://www.onekingslane.com/sales/12058

I'm actually really curious about D. Auzoux; it seems like the actual illustrator is someone named P. Sougy, but I can't find anything about him.

I've found many of these and other vintage charts at an australian website http://www.empiricalstyle.com/