Index: distiller.lua
==================================================================
--- distiller.lua
+++ distiller.lua
@@ -7,11 +7,12 @@
 }
 
 local function
 findextract(herb)
 	for name, e in pairs(sorcery.data.extracts) do
-		if e[1] == herb then
+		local found = false
+		if sorcery.lib.item.groupmatch(e[1], herb) then
 			return name, {
 				color = e[2];
 				reqamt = e[3] or 3;
 				reqtime = e[4] or 75;
 			}

Index: lib/item.lua
==================================================================
--- lib/item.lua
+++ lib/item.lua
@@ -33,12 +33,12 @@
 			local is = ItemStack(identity)
 			identity,count = is:get_name(), is:get_count()
 		end
 	end
 
-	local stack = ItemStack(item)
 	if sorcery.lib.str.beginswith(identity, 'group:') then
+		local stack = ItemStack(item)
 		local groups = sorcery.lib.str.explode(string.sub(identity,7), ',')
 		for _,g in pairs(groups) do
 			local rn,rv = sorcery.lib.tbl.split(g,'=')
 			local gv = minetest.get_item_group(stack:get_name(), rn)
 			if rv then

Index: lib/node.lua
==================================================================
--- lib/node.lua
+++ lib/node.lua
@@ -183,11 +183,11 @@
 
 	tree_is_live = function(pos, checklight) -- VERY EXPENSIVE FUNCTION
 		-- this is going to require some explanation.
 		--
 		-- for various purposes, we want to be able to tell the difference between
-		-- a tree that has grown naturally from the grown vs. a couple of trunk nodes
+		-- a tree that has grown naturally from the ground vs. a couple of trunk nodes
 		-- that the player has jammed together, even if she's built her own counterfeit
 		-- tree. unfortunately, mtg provides no easy way to do this. the only 
 		-- difference between a cluster of trunk blocks and a real tree is that the
 		-- real tree will have a specific kind of leaves attached with their param2
 		-- set to 1 so that they can be distinguished for the purpose of leaf cleaning.
@@ -412,11 +412,11 @@
 			local n = minetest.get_node(sum)
 			if n.name == 'ignore' then
 				minetest.load_area(sum)
 				n = minetest.get_node(sum)
 			end
-			fn(sum, n)
+			if fn(sum, n) == false then break end
 		end
 	end;
 
 	amass = amass;