klu bdud nag po Black Naga's Devil; bonnet Bell-flower (Lat. Codonopsis).;
rtswa mchog klu bdud rdo rje nag po Supreme Herb, Black Diamond Naga's Devil, the bonnet bell-flower (Codonopsis).;
http://www.mdidea.com/products/new/new002.html

http://www.lankalibrary.com/myths/nagas.html

http://74.125.47.132/search?q=cache:mS8LLb8JA94J:www.bhutanstudies.org.bt/admin/pubFiles/v5-6.pdf+black+naga+devil+flower&cd=6&hl=en&ct=clnk&gl=za

http://himalaya.socanth.cam.ac.uk/collections/journals/jbs/pdf/JBS_05_06.pdf

http://www.dhammawiki.com/index.php?title=Mount_Potala

http://books.google.co.za/books?id=IA1VhyLNIccC&pg=PA269&lpg=PA269&dq=black+diamond+naga+devil&source=bl&ots=L283aUNPsG&sig=pRJqqaUU0SnOI5q0bxHKa5diX1o&hl=en&ei=WjYJSteEG4SGtgeTydDnCw&sa=X&oi=book_result&ct=result&resnum=3