-- Original bounded seasonal appearance. No timers, world lists or clock replay.
return function(hearth, api)
	local S = {COLUMN_HEIGHT = 12, MAX_COLUMN_SWAPS = 12}
	local variants, canonical, availability = {}, {}, {}
	local function variant(kind, season, texture, mesh)
		variants[kind] = variants[kind] or {}
		local short = kind .. "_" .. season:lower()
		variants[kind][season] = {name="hearth:"..short, texture=texture, mesh=mesh}
		canonical["hearth:"..short] = kind
	end
	for _, kind in ipairs({"tree_seedling", "young_tree", "mature_tree", "leaves"}) do
		for _, season in ipairs({"Spring", "Autumn", "Winter"}) do
			local suffix = season:lower()
			local mesh = kind ~= "leaves" and ("hearth_"..kind
				.. (season == "Winter" and kind ~= "tree_seedling" and "_winter" or "") .. ".obj") or nil
			variant(kind, season, "hearth_" .. (kind == "leaves" and "leaves" or "tree_atlas") .. "_" .. suffix .. ".png", mesh)
		end
	end
	for _, kind in ipairs({"meadow_grass", "fern", "wildflowers"}) do
		variant(kind, "Winter", "hearth_"..kind.."_dormant.png")
		if kind == "wildflowers" then variant(kind, "Autumn", "hearth_wildflowers_dormant.png") end
	end
	-- Patch nodes and picked food items have different names: never overwrite a
	-- registered node with a craftitem, and never let picked food reset a patch.
	variant("spring_greens_patch", "Spring", "hearth_spring_greens.png")
	variant("autumn_mushrooms_patch", "Autumn", "hearth_autumn_mushrooms.png")
	for kind in pairs(variants) do canonical["hearth:"..kind] = kind end
	-- Extensions are installed by botany/diversity before node registration. Missing
	-- bases in minimal mocks/optional content are skipped, never asserted.
	function S.add_variants(kind, definitions, active_seasons)
		assert(type(kind)=="string" and kind:match("^[a-z_]+$"), "invalid flora kind")
		canonical["hearth:"..kind] = kind
		for season, def in pairs(definitions or {}) do
			assert(({Spring=true,Summer=true,Autumn=true,Winter=true})[season], "invalid season")
			variant(kind, season, assert(def.texture), def.mesh)
		end
		availability[kind] = active_seasons
	end
	function S.kind(n)
		local name = type(n) == "table" and n.name or n
		return type(name) == "string" and (canonical[name] or name:match("^hearth:(.+)$")) or nil
	end
	function S.season(now)
		local climate = hearth.climate_at and hearth.climate_at(now or os.time())
		return climate and climate.season or "Summer"
	end
	function S.name_for(kind, now)
		kind = S.kind(kind) or kind
		local v = variants[kind] and variants[kind][S.season(now)]
		return v and v.name or "hearth:"..kind
	end
	function S.available(kind, now)
		kind = S.kind(kind) or kind
		local season = S.season(now)
		if availability[kind] then return availability[kind][season] == true end
		if kind == "spring_greens_patch" then return season == "Spring" end
		if kind == "autumn_mushrooms_patch" then return season == "Autumn" end
		if kind == "wildflowers" then return season == "Spring" or season == "Summer" end
		return not variants[kind] or season ~= "Winter"
	end
	function S.names()
		local names = {}
		for name in pairs(canonical) do names[#names+1] = name end
		return names
	end
	function S.reconcile(p, n, now)
		-- Appearance alone can change a claimed/hand-placed plant, but never its
		-- provenance, age, harvest deadline, dig permission, drops or inventory.
		n = n or api.get_node_or_nil(p)
		if not n or not canonical[n.name] then return false end
		local protection = hearth.external_protected or api.is_protected
		if protection and protection(p, "") then return false end
		local target = S.name_for(canonical[n.name], now)
		if n.name == target then return false end
		-- Recheck loaded identity before swapping; no set_node metadata erasure.
		local current = api.get_node_or_nil(p)
		if not current or current.name ~= n.name then return false end
		api.swap_node(p, {name=target, param1=current.param1, param2=current.param2})
		return true
	end
	function S.register()
		local names = {}
		for kind, seasons in pairs(variants) do
			local base_name = "hearth:"..kind
			local base = (api.registered_nodes or {})[base_name]
			if base then
				names[#names+1] = base_name
				for _, v in pairs(seasons) do
					local def = {}
					for k, value in pairs(base) do def[k] = value end
					def.groups = {}
					for k, value in pairs(base.groups or {}) do def.groups[k] = value end
					def.groups.not_in_creative_inventory = 1
					-- A stage may now be a bark cube rather than the old sculpted
					-- tree. Recolour foliage/sprites only; never flatten end-grain
					-- and bark faces or reintroduce an obsolete mesh on a cube.
					if base.drawtype ~= "normal" then
						def.tiles = {v.texture}
						if base.inventory_image then def.inventory_image = v.texture end
						if base.wield_image then def.wield_image = v.texture end
					end
					if base.drawtype == "mesh" and v.mesh then def.mesh = v.mesh end
					def.drop = base.drop == nil and base_name or base.drop
					if not api.registered_nodes[v.name] then api.register_node(v.name, def) end
					names[#names+1] = v.name
				end
			end
		end
		api.register_lbm({name="hearth:seasonal_flora", label="Reconcile seasonal flora appearance",
			nodenames=names, run_at_every_load=true, action=function(p) S.reconcile(p) end})
	end
	return S
end