The cactaceae, the original! (Britton and rose) + many more

[Bushpig]

Britton and Roses classification of cacti:

http://www.cactuspro.com/biblio/en:britton_et_rose

All 4 volumes in electronic format!

+ many others :

http://www.cactuspro.com/biblio/

Bushpig

[olivertwist]

thank you, thank you. i was thinking about looking for something like this just the other day while working in the herbarium.

[Bushpig]

Not a problem, that website seems a great resource.  What I would like ot know is what is the current definitive Cactus family key/guide of the present?  And how much does it differ from this original work of Britton and Rose ?

Bushpig