What is glooi in English? Warning! As is discussed in the comments to the answer, the plant and tuber may be poisonous and must be cooked by experts.

I went to a village market in NE Thailand. They had many products from "the jungle". For lunch I had steamed, shredded coco-nut, pumpkin and a white tuber (?) they called "glooi".
 I assume the "glooi" is sliced (and steamed) in the picture below.

Does anyone know more about "glooi", it's English name etc?
Warning! The plant and tuber may be poisonous and must be cooked by experts. See comments.

Some Thai friends had eaten this tuber when they were young and helped me surf the Internet for it.

It is pronounced glooi (กลอย).

Scientifically it would be
Dioscorea hispida Dennst
http://www.thaicrudedrug.com/main.php?action=viewpage&amp;pid=14

My dictionary translates it as wild yam, but that is probably a wide definition. It is definitely different from other yam that resembles sweet potato and  is sometimes purple. (Yam in Thai language is "man".)