Stillman and Birn Epsilon Series Hardbound Sketchbook.
Faber-Castell Polychromos colored pencils.
I'm really amazed of what I have done here, specially in terms of being patient.
I normally do fast sketches or a page which takes me lot less than one day to finish. This page has been done through almost a week ...not working continuously though.
Each butterfly took me around three hours to complete.
Working with colored is very rewarding but takes time. You don't realize that while drawing because it is very relaxing, it is almost meditative. You can achieve great rich colors with lots of layers and like watercolors you can have a limited palette because you can mix the colored pencils as well.
I highly recommend her book if you want to try serious drawings with colored pencils, even if you don't want to draw flowers. She only uses 20 of the 120 colors available in the Polychromos range and does the most beautiful botanical illustrations.
I'm very happy with my butterflies, I still look at them and can't believe I made them!!!