We have a continuity problem, I fear. The article on reannual plants says:-
"the Rehigreed Province in the Agatean Empire is another. The reannual Vul Nuts are mentioned in The Colour of Magic as being grown in the latter place, and when harvested they make a drink called Ghlen Livid....."
The problem is, The Discworld Mapp places the Rehigreed Province in the opposite corner of the Discworld from Agatea - the two could not be further apart if you tried. Either the Rehigreed is a "lost colony" of the Central Continent originally settled by Agateans, or else in between The Colour of Magic amnd The Discworld Mapp this fine detail was lost. --AgProv 20:39, 14 November 2010 (CET)