What dialect/topolect is 凉薯 a part of? 《现代汉语大词典》defines 凉薯 as:


  方言。即豆薯。有的地方也叫地瓜。藤本植物, 花色浅蓝或白色, 结荚, 种子有毒, 块根像甘薯, 可食。


It was the 方言 part that threw me off here.

Baidu Baike just calls it a


  别称


other resources also just say something like:


  又名


I figured 凉薯 was just MSM but apparently it isn't.

What dialect/topolect is 凉薯 a part of? (if not Modern Standard Mandarin.)
According to Wiktionary:




柳州話 (Liuzhou Mandarin)
萍鄉話 (Pingxiang Gan)
南寧話 (Nanning Pinghua)
長沙話 (Changsha Xiang)
婁底話 (Loudi Xiang)


These topolects correspond to the areas highlighted in the light green circles above.