diff --git a/API.txt b/plants_lib/API.txt
similarity index 53%
rename from API.txt
rename to plants_lib/API.txt
index 8075865..8f6455c 100644
--- a/API.txt
+++ b/plants_lib/API.txt
@@ -1,6 +1,6 @@
 This document describes the Plantlife mod API.
 
-Last revision: 2014-05-24
+Last revision: 2015-02-16
 
 
 =========
@@ -64,9 +64,9 @@ biome = {
 	spawn_delay = number,	-- same as sdelay, above.
 	spawn_chance = number,	-- same as schance, above.
 	spawn_surfaces = {table}, -- List of node names on which the plants
-				-- should be spawned.  As with the single-
-				-- node "ssurface" option in the legacy API,
-				-- you should not put stone, air, etc. here.
+				-- should be spawned.  As with the single-node "ssurface"
+				-- option in the legacy API, you should not put stone, air,
+				-- etc. here.
 
 	---- From here down are a number of optional parameters.  You will
 	---- most likely want to use at least some of these to limit how and
@@ -74,151 +74,132 @@ biome = {
 
 	avoid_nodes = {table},	-- same meaning as savoid, above
 	avoid_radius = num,	-- same as sradius
-	seed_diff = num,	-- The Perlin seed difference value passed to
-				-- the minetest.get_perlin() function.
-				-- Used along with the global Perlin controls
-				-- below to create the "biome" in which the
-				-- plants will spawn.  Defaults to 0 if not
-				-- provided.
-	light_min = num,	-- Minimum amount of light necessary to make a
-				-- plant spawn.  Defaults to 0.
-	light_max = num,	-- Maximum amount of light needed to spawn. 
-				-- Defaults to the engine's MAX_LIGHT value of
-				-- 14.
-	neighbors = {table},	-- List of neighboring nodes that need to be
-				-- immediately next to the node the plant is
-				-- about to spawn on. Can also be a string
-				-- with a single node name.  It is both passed
-				-- to the ABM as the "neighbors" parameter,
-				-- and is used to manually check the 
-				-- adjacent nodes.  It only takes one of these
-				-- for the spawn routine to mark the target as
-				-- spawnable.  Defaults to nil (ignored).
-	ncount = num,		-- There must be at least this many of the
-				-- above neighbors in the eight spaces
-				-- immediately surrounding the node the plant
-				-- is about to spawn on for it to happen.  If
-				-- not provided, this check is disabled.
-	facedir = num,		-- The value passed to the param2 variable
-				-- when adding the node to the map.  Defaults
-				-- to 0.  Be sure that the value you use here
-				-- (and the range thereof) is appropriate for
-				-- the type of node you're spawning.
-	random_facedir = {table}, -- If set, the table should contain two
-				-- values. If they're both provided, the
-				-- spawned plant will be given a random
-				-- facedir value in the range specified by
-				-- these two numbers.  Overrides the facedir
-				-- parameter above, if it exists.  Use {0,3}
-				-- if you want the full range for wallmounted
-				-- nodes, or {2,5} for most everything else,
-				-- or any other pair of numbers in the 0 to 5 
-				-- range, as appropriate for the node you want
-				-- to spawn.
-	verticals_list = {table}, -- List of nodes that should be considered
-				-- to be natural walls.
-	alt_wallnode = "string", -- If specified, this node will be 
-				-- substituted in place of the plant(s)
-				-- defined by spawn_plants above, if the spawn
-				-- target has one or more adjacent walls.  In
-				-- such a case, the two above facedir
-				-- parameters will be ignored.
-	depth_max = num,	-- If the object spawns on top of a water
-				-- source, the water must be at most this
-				-- deep.  Defaults to 1 node.
-	min_elevation = num,	-- Surface must be at this altitude or higher
-				-- to spawn at all.  Defaults to -31000...
-	max_elevation = num,	-- ...but must be no higher than this
-				-- altitude.  Defaults to +31000.
-	near_nodes = {table},	-- List of nodes that must be somewhere in the
-				-- vicinity in order for the plant to spawn.
-				-- Can also be a string with a single node
-				-- name.  If not provided, this check is
-				-- disabled.
+	seed_diff = num,	-- The Perlin seed difference value passed to the
+						-- minetest.get_perlin() function.  Used along with
+						-- the global Perlin controls below to create the
+						-- "biome" in which the plants will spawn.  Defaults
+						-- to 0 if not provided.
+	light_min = num,	-- Minimum amount of light necessary to make a plant
+						-- spawn.  Defaults to 0.
+	light_max = num,	-- Maximum amount of light needed to spawn.  Defaults
+						-- to the engine's MAX_LIGHT value of 14.
+	neighbors = {table}, -- List of neighboring nodes that need to be
+						-- immediately next to the node the plant is about to
+						-- spawn on. Can also be a string with a single node
+						-- name.  It is both passed to the ABM as the
+						-- "neighbors" parameter, and is used to manually
+						-- check the adjacent nodes.  It only takes one of
+						-- these for the spawn routine to mark the target as
+						-- spawnable.  Defaults to nil (ignored).
+	ncount = num,		-- There must be at least this many of the above
+						-- neighbors in the eight spaces immediately
+						-- surrounding the node the plant is about to spawn on
+						-- for it to happen.  If not provided, this check is
+						-- disabled.
+	facedir = num,		-- The value passed to the param2 variable when adding
+						-- the node to the map.  Defaults to 0.  Be sure that
+						-- the value you use here (and the range thereof) is
+						-- appropriate for the type of node you're spawning.
+	random_facedir = {table}, -- If set, the table should contain two values.
+						-- If they're both provided, the spawned plant will be
+						-- given a random facedir value in the range specified
+						-- by these two numbers.  Overrides the facedir
+						-- parameter above, if it exists.  Use {0,3} if you
+						-- want the full range for wallmounted nodes, or {2,5}
+						-- for most everything else, or any other pair of
+						-- numbers appropriate for the node you want to spawn.
+	depth_max = num,	-- If the object spawns on top of a water source, the
+						-- water must be at most this deep.  Defaults to 1.
+	min_elevation = num, -- Surface must be at this altitude or higher to
+						-- spawn at all.  Defaults to -31000...
+	max_elevation = num, -- ...but must be no higher than this altitude.
+						-- Defaults to +31000.
+	near_nodes = {table}, -- List of nodes that must be somewhere in the
+						-- vicinity in order for the plant to spawn. Can also
+						-- be a string with a single node name.  If not
+						-- provided, this check is disabled.
 	near_nodes_size = num,	-- How large of an area to check for the above
-				-- node.  Specifically, this checks a flat
-				-- horizontal area centered on the node to be
-				-- spawned on.  Defaults to 0, but is ignored
-				-- if the above near_nodes value is not set.
-	near_nodes_vertical = num, -- Used with the size value above, this
-				-- extends the vertical range of the near 
-				-- nodes search.  Basically, this turns the
-				-- flat region described above into a cuboid
-				-- region.  The area to be checked will extend
-				-- this high AND this low above/below the
-				-- target node, centered thereon.  Defaults to
-				-- 1 (check only the layer above, the layer
-				-- at, and the layer below the target node),
-				-- but is ignored if near_nodes is not set.
-	near_nodes_count = num,	-- How many of the above nodes must be within
-				-- that radius.	Defaults to 1 but is ignored
-				-- if near_nodes isn't set.  Bear in mind that
-				-- the total area to be checked is equal to
-				-- (near_nodes_size^2)*near_nodes_vertical*2.
-				-- so for example, if size is 10 and vertical
-				-- is 4 then the area is (10^2)*8 = 800 nodes
-				-- in size, so you'll want to make sure you
-				-- specify a value appropriate for the amount
-				-- in question.
-	air_size = num,		-- How large of an area to check for air
-				-- above and around the target.  If omitted,
-				-- only the space above the target is checked.
-				-- This does not check for air at the sides or
-				-- below the target.
-	air_count = num,	-- How many of the surrounding nodes need to
-				-- be air for the above check to return true.
-				-- If omitted, only the space above the target
-				-- is checked.
-	plantlife_limit = num,	-- The value compared against the generic
-				-- "plants can grow here" Perlin noise layer.
-				-- Smaller numbers result in more abundant
-				-- plants.  Range of -1 to +1, with values in 
-				-- the range of about 0 to 0.5 being most
-				-- useful.  Defaults to 0.1.
-	temp_min = num,		-- Minimum temperature needed for the desired
-				-- object to spawn.  This is a 2d Perlin
-				-- value, which has an inverted range of +1 to
-				-- -1.  Larger values represent *colder*
-				-- temperatures, so this value is actually the
-				-- upper end of the desired Perlin range.  See
-				-- the temperature map section at the bottom
-				-- of this document for details on how these
-				-- values work.  Defaults to +1 (unlimited
-				-- coldness).
-	temp_max = num,		-- Maximum temperature/lower end of the Perlin
-				-- range.  Defaults to -1 (unlimited heat).
-	humidity_min = num,	-- Minimum humidity for the plant to spawn in.
-				-- Like the temperature map, this is a Perlin
-				-- value where lower numbers mean more
-				-- humidity in the area.  Defaults to +1 (0%
-				-- relative humidity).
+						-- node.  Specifically, this checks a flat, horizontal
+						-- area centered on the node to be spawned on.
+						-- Defaults to 0, but is ignored if the above
+						-- near_nodes value is not set.
+	near_nodes_vertical = num, -- Used with the size value above, this extends
+						-- the vertical range of the near nodes search.
+						-- Basically, this turns the flat region described
+						-- above into a cuboid region.  The area to be checked
+						-- will extend this high and this low above/below the
+						-- target node, centered thereon.  Defaults to 1 (only
+						-- check the layer above, the layer at, and the layer
+						-- below the target node), but is ignored if
+						-- near_nodes is not set.
+	near_nodes_count = num,	-- How many of the above nodes must be within that
+						-- radius.  Defaults to 1 but is ignored if near_nodes
+						-- isn't set.  Bear in mind that the total area to be
+						-- checked is equal to:
+						-- (near_nodes_size^2)*near_nodes_vertical*2 
+						-- For example, if size is 10 and vertical is 4, then
+						-- the area is (10^2)*8 = 800 nodes in size, so you'll
+						-- want to make sure you specify a value appropriate
+						-- for the size of the area being tested.
+	air_size = num,		-- How large of an area to check for air above and
+						-- around the target.  If omitted, only the space
+						-- above the target is checked.  This does not check
+						-- for air at the sides or below the target.
+	air_count = num,	-- How many of the surrounding nodes need to be air
+						-- for the above check to return true. If omitted,
+						-- only the space above the target is checked.
+	plantlife_limit = num, -- The value compared against the generic "plants
+						-- can grow here" Perlin noise layer. Smaller numbers
+						-- result in more abundant plants.  Range of -1 to +1,
+						-- with values in the range of about 0 to 0.5 being
+						-- most useful.  Defaults to 0.1.
+	temp_min = num,		-- Minimum temperature needed for the desired object
+						-- to spawn.  This is a 2d Perlin value, which has an
+						-- inverted range of +1 to -1.  Larger values
+						-- represent *colder* temperatures, so this value is
+						-- actually the upper end of the desired Perlin range.
+						-- See the temperature map section at the bottom of
+						-- this document for details on how these values work.
+						-- Defaults to +1 (unlimited coldness).
+	temp_max = num,		-- Maximum temperature/lower end of the Perlin range.
+						-- Defaults to -1 (unlimited heat).
+	humidity_min = num,	-- Minimum humidity for the plant to spawn in. Like
+						-- the temperature map, this is a Perlin value where
+						-- lower numbers mean more humidity in the area.
+						-- Defaults to +1 (0% humidity).
 	humidity_max = num,	-- Maximum humidity for the plant to spawn at.
-				-- Defaults to -1 (100% humidity).
-	spawn_on_side = bool,	-- Set this to true to spawn the node on one
-				-- side of the target node rather than the
-				-- top.  The code will search for an airspace
-				-- to the side of the target, then spawn the
-				-- plant at the first one found.  The above
-				-- facedir and random_facedir parameters are
-				-- ignored in this case.  If the above
-				-- parameters for selecting generic wall nodes
-				-- are provided, this option is ignored.
-				-- Important note: the facedir values assigned
-				-- by this option only make sense with
-				-- wallmounted nodes (nodes which don't use
-				-- facedir won't be affected).
+						-- Defaults to -1 (100% humidity).
+	verticals_list = {table}, -- List of nodes that should be considered to be
+						-- natural walls.
+	alt_wallnode = "string", -- If specified, this node will be substituted in
+						-- place of the plant(s) defined by spawn_plants
+						-- above, if the spawn target has one or more adjacent
+						-- walls.  In such a case, the two above facedir
+						-- parameters will be ignored.
+	spawn_on_side = bool, -- Set this to true to immediately spawn the node on
+						-- one side of the target node rather than the top.
+						-- The code will search for an airspace to the side of
+						-- the target, then spawn the plant at the first one
+						-- found.  The above facedir and random_facedir
+						-- parameters are ignored in this case.  If the above
+						-- parameters for selecting generic wall nodes are
+						-- provided, this option is ignored.  Important note:
+						-- the facedir values assigned by this option only
+						-- make sense with wallmounted nodes (nodes which
+						-- don't use facedir won't be affected).
+	choose_random_wall = bool, -- if set to true, and searching for walls is
+						-- being done, just pick any random wall if there is
+						-- one, rather than returning the first one.
 	spawn_on_bottom = bool,	-- If set to true, spawn the object below the
-				-- target node instead of above it.  The above
-				-- spawn_on_side variable takes precedence
-				-- over this one if both happen to be true.
-				-- When using this option with the random
-				-- facedir function above, the values given to
-				-- the facedir parameter are for regular
-				-- nodes, not wallmounted.
-	spawn_replace_node = bool, -- If set to true, the target node itself
-				-- is replaced by the spawned object.
-				-- Overrides the spawn_on_bottom and
-				-- spawn_on_side settings.
+						-- target node instead of above it.  The above
+						-- spawn_on_side variable takes precedence over this
+						-- one if both happen to be true. When using this
+						-- option with the random facedir function above, the
+						-- values given to the facedir parameter are for
+						-- regular nodes, not wallmounted.
+	spawn_replace_node = bool, -- If set to true, the target node itself is
+						-- replaced by the spawned object.  Overrides the
+						-- spawn_on_bottom and spawn_on_side settings.
 }
 
 [*] spawn_plants must be either a table or a string.  If it's a table, the
@@ -250,87 +231,78 @@ here than are available in the ABM-based spawner, as some stuff doesn't make
 sense at map-generation time.
 
 biome = {
-	surface = something,	-- What node(s).  May be a string such as
-				-- "default:dirt_with_grass" or a table with
-				-- multiple such entries.
+	surface = something, -- What node(s).  May be a string such as
+						-- "default:dirt_with_grass" or a table with
+						-- multiple such entries.
 
 	---- Everything else is optional, but you'll definitely want to use
 	---- some of these other fields to limit where and under what
 	---- conditions the objects are spawned.
 	
-	below_nodes = {table},	-- List of nodes that must be below the target
-				-- node.  Useful in snow biomes to keep
-				-- objects from spawning in snow that's on the
-				-- wrong surface for that object.
-	avoid_nodes = {table},	-- List of nodes to avoid when spawning.
-				-- Groups are not supported here.
-	avoid_radius = num,	-- how much distance to leave between the
-				-- object to be added and the objects to be
-				-- avoided.  If this or the avoid_nodes value
-				-- is nil or omitted, this check is skipped.
-				-- Avoid using excessively large radii or you
-				-- will slow down the map generator.
-	rarity = num,		-- how rare should this object be in its
-				-- biome? Larger values make objects more
-				-- rare, via:  math.random(1,100) > this
-	max_count = num,	-- The absolute maximum number of your object
-				-- that should be allowed to spawn in a 5x5x5
-				-- mapblock area (80x80x80 nodes).  Defaults
-				-- to 5, but be sure you set this to some 
-				-- reasonable value depending on your object
-				-- and its size if 5 is insufficient.
-	seed_diff = num,	-- perlin seed-diff value.  Defaults to 0, 
-				-- which causes the function to inherit the
-				-- global value of 329.
-	neighbors = {table},	-- What ground nodes must be right next to and
-				-- at the same elevation as the node to be
-				-- spawned on.
-	ncount = num,		-- at least this many of the above nodes must
-				-- be next to the node to spawn on.  Any value
-				-- greater than 8 will probably cause the code
-				-- to never spawn anything.  Defaults to 0.
-	depth = num,		-- how deep/thick of a layer the spawned-on
-				-- node must be.  Typically used for water.
-	min_elevation = num,	-- minimum elevation in meters/nodes.
-				-- Defaults to -31000 (unlimited).
-	max_elevation = num,	-- maximum elevation.  Defaults to +31000
-				-- (unlimited).
-	near_nodes = {table},	-- what nodes must be in the general vicinity
-				-- of the object being spawned.
-	near_nodes_size = num,	-- how wide of a search area to look for 
-				-- the nodes in that list.
-	near_nodes_vertical = num, -- How high/low of an area to search from
-				-- the target node.
-	near_nodes_count = num,	-- at least this many of those nodes must be
-				-- in the area.
-	plantlife_limit = num,	-- The value compared against the generic
-				-- "plants can grow here" Perlin noise layer.
-				-- Smaller numbers result in more abundant
-				-- plants.  Range of -1 to +1, with values in 
-				-- the range of about 0 to 0.5 being most
-				-- useful.  Defaults to 0.1.
-	temp_min = num,		-- coldest allowable temperature for a plant
-				-- to spawn (that is, the highest Perlin
-				-- temperature map value).
-	temp_max = num,		-- warmest allowable temperature to spawn a
-				-- plant (lowest Perlin temperature value).
-	verticals_list = {table}, -- Same as with the spawn_on_surfaces
-				-- function.
-	check_air = bool,	-- Flag to tell the mapgen code to check for
-				-- air above the spawn target.  Defaults to
-				-- true if not explicitly set to false.
-	delete_above = bool,	-- Flag to tell the mapgen code to delete the
-				-- two nodes directly above the spawn target
-				-- just before adding the plant or tree.
-				-- Useful when generating in snow biomes.
-				-- Defaults to false.
+	below_nodes = {table}, -- List of nodes that must be below the target
+						-- node.  Useful in snow biomes to keep objects from
+						-- spawning in snow that's on the wrong surface for
+						-- that object.
+	avoid_nodes = {table}, -- List of nodes to avoid when spawning. Groups are
+						-- not supported here.
+	avoid_radius = num,	-- How much distance to leave between the object to be
+						-- added and the objects to be avoided.  If this or
+						-- the avoid_nodes value is nil/omitted, this check is
+						-- skipped.  Avoid using excessively large radii.
+	rarity = num,		-- How rare should this object be in its biome? Larger
+						-- values make objects more rare, via:
+						-- math.random(1,100) > this
+	max_count = num,	-- The absolute maximum number of your object that
+						-- should be allowed to spawn in a 5x5x5 mapblock area
+						-- (80x80x80 nodes).  Defaults to 5, but be sure you
+						-- set this to some reasonable value depending on your
+						-- object and its size if 5 is insufficient.
+	seed_diff = num,	-- Perlin seed-diff value.  Defaults to 0, which
+						-- causes the function to inherit the global value of
+						-- 329.
+	neighbors = {table}, -- What ground nodes must be right next to and at the
+						-- same elevation as the node to be spawned on.
+	ncount = num,		-- At least this many of the above nodes must be next
+						-- to the node to spawn on.  Any value greater than 8
+						-- will probably cause the code to never spawn
+						-- anything.  Defaults to 0.
+	depth = num,		-- How deep/thick of a layer the spawned-on node must
+						-- be.  Typically used for water.
+	min_elevation = num, -- Minimum elevation in meters/nodes.  Defaults to
+						-- -31000 (unlimited).
+	max_elevation = num, -- Max elevation.  Defaults to +31000 (unlimited).
+	near_nodes = {table}, -- what nodes must be in the general vicinity of the
+						-- object being spawned.
+	near_nodes_size = num, -- how wide of a search area to look for the nodes
+						-- in that list.
+	near_nodes_vertical = num, -- How high/low of an area to search from the
+						-- target node.
+	near_nodes_count = num,	-- at least this many of those nodes must be in
+						-- the area.
+	plantlife_limit = num, -- The value compared against the generic "plants
+						-- can grow here" Perlin noise layer.  Smaller numbers
+						-- result in more abundant plants.  Range of -1 to +1,
+						-- with values in the range of about 0 to 0.5 being
+						-- most useful.  Defaults to 0.1.
+	temp_min = num,		-- Coldest allowable temperature for a plant to spawn
+						-- (that is, the largest Perlin value).
+	temp_max = num,		-- warmest allowable temperature to spawn a plant
+						-- (lowest Perlin value).
+	verticals_list = {table}, -- Same as with the spawn_on_surfaces function.
+	check_air = bool,	-- Flag to tell the mapgen code to check for air above
+						-- the spawn target.  Defaults to true if not
+						-- explicitly set to false.  Set this to false VERY
+						-- SPARINGLY, as it will slow the map generator down.
+	delete_above = bool, -- Flag to tell the mapgen code to delete the two
+						-- nodes directly above the spawn target just before
+						-- adding the plant or tree.  Useful when generating
+						-- in snow biomes.  Defaults to false.
 	delete_above_surround = bool, -- Flag to tell the mapgen code to also
-				-- delete the four nodes surrounding the above
-				-- space, and the four nodes above those,
-				-- resulting in a two-node-deep cross-shaped
-				-- empty region above the spawn target.
-				-- Useful when adding trees to snow biomes.
-				-- Defaults to false.
+						-- delete the five nodes surrounding the above space,
+						-- and the five nodes above those, resulting in a two-
+						-- node-deep cross-shaped empty region above/around
+						-- the spawn target.  Useful when adding trees to snow
+						-- biomes.  Defaults to false.
 	spawn_replace_node = bool, -- same as with the ABM spawner.
 	random_facedir = {table}, -- same as with the ABM spawner.
 }
@@ -370,61 +342,53 @@ into something else over time.  This function has no return value, and accepts
 a biome definition table as the only parameter.  These are defined like so:
 
 options = {
-	grow_plant = "string",	-- Name of the node to be grown into something
-				-- else.  This value is passed to the ABM as
-				-- the "nodenames" parameter, so it is the
-				-- plants themselves that are the ABM trigger,
-				-- rather than the ground they spawned on.  A
-				-- plant will only grow if the node above it
-				-- is air.  Can also be a table, but note that
-				-- all nodes referenced therein will be grown
-				-- into the same object.
-	grow_delay = num,	-- Passed as the ABM "interval" parameter, as
-				-- with spawning.
+	grow_plant = "string", -- Name of the node to be grown into something
+						-- else.  This value is passed to the ABM as the
+						-- "nodenames" parameter, so it is the plants
+						-- themselves that are the ABM trigger, rather than
+						-- the ground they spawned on.  A plant will only grow
+						-- if the node above it is air.  Can also be a table,
+						-- but note that all nodes referenced therein will be
+						-- grown into the same object.
+	grow_delay = num,	-- Passed as the ABM "interval" parameter, as with
+						-- spawning.
 	grow_chance = num,	-- Passed as the ABM "chance" parameter.
 	grow_result = "string",	-- Name of the node into which the grow_plant
-				-- node(s) should transform when the ABM
-				-- executes.
+						-- node(s) should transform when the ABM executes.
 
 	---- Everything from here down is optional.
 
 	dry_early_node = "string", -- This value is ignored except for jungle
-				-- grass (a corner case needed by that mod),
-				-- where it indicates which node the grass
-				-- must be on in order for it to turn from
-				-- the short size to "default:dry_shrub"
-				-- instead of the medium size.
-	grow_nodes = {table},	-- One of these nodes must be under the plant
-				-- in order for it to grow at all.  Normally
-				-- this should be the same as the list of 
-				-- surfaces passed to the spawning ABM as the
-				-- "nodenames" parameter.  This is so that the
-				-- plant can be manually placed on something
-				-- like a flower pot or something without it
-				-- growing and eventually dieing.  Defaults to
-				-- "default:dirt_with_grass".
+						-- grass (a corner case needed by that mod), where it
+						-- indicates which node the grass must be on in order
+						-- for it to turn from the short size to
+						-- "default:dry_shrub" instead of the medium size.
+	grow_nodes = {table}, -- One of these nodes must be under the plant in
+						-- order for it to grow at all.  Normally this should
+						-- be the same as the list of surfaces passed to the
+						-- spawning ABM as the "nodenames" parameter.  This is
+						-- so that the plant can be manually placed on
+						-- something like a flower pot or something without it
+						-- necessarily growing and perhaps dieing.  Defaults
+						-- to "default:dirt_with_grass".
 	facedir = num,		-- Same as with spawning a plant.
-	need_wall = bool,	-- Set this to true if you the plant needs to
-				-- grow against a wall.  Defaults to false.
-	verticals_list = {table}, -- List of nodes that should be considered
-				-- to be wall surfaces when growing the plant
-				-- vertically.  If not provided, the walls
-				-- check is skipped.
+	need_wall = bool,	-- Set this to true if you the plant needs to grow
+						-- against a wall.  Defaults to false.
+	verticals_list = {table}, -- same as with spawning a plant.
+	choose_random_wall = bool, -- same as with spawning a plant.
 	grow_vertically = bool,	-- Set this to true if the plant needs to grow
-				-- vertically, as in climbing poison ivy.
-				-- Defaults to false.
-	height_limit = num,	-- Set this to limit how tall the desired node
-				-- can grow.  The mod will search straight
-				-- down from the position being spawned at to
-				-- find a ground node, set via the parameter
-				-- below. Defaults to 5 nodes.
-	ground_nodes = {table},	-- What nodes should be treated as "the
-				-- ground" below a vertically-growing plant.
-				-- Usually this should be the same as the
-				-- grow_nodes table, but might also include,
-				-- for example, water or some other
-				-- surrounding material.  Defaults to
-				-- "default:dirt_with_grass".
+						-- vertically, as in climbing poison ivy. Defaults to
+						-- false.
+	height_limit = num,	-- Set this to limit how tall the desired node can
+						-- grow.  The mod will search straight down from the
+						-- position being spawned at to find a ground node,
+						-- set via the field below. Defaults to 5 nodes.
+	ground_nodes = {table},	-- What nodes should be treated as "the ground"
+						-- below a vertically-growing plant. Usually this
+						-- should be the same as the grow_nodes table, but
+						-- might also include, for example, water or some
+						-- other surrounding material.  Defaults to
+						-- "default:dirt_with_grass".
 	grow_function = something, -- [*] see below.
 	seed_diff = num,	-- [*] see below.
 }
@@ -457,13 +421,16 @@ and grow_result is ignored.
 
 
 =====
-find_adjacent_wall(pos, verticals)
+find_adjacent_wall(pos, verticals, randomflag)
 
 Of the few helper functions, this one expects a position parameter and a table
 with the list of nodes that should be considered as walls.  The code will
 search around the given position for a neighboring wall, returning the first
 one it finds as a facedir value, or nil if there are no adjacent walls.
 
+If randomflag is set to true, the function will just return the facedir of any
+random wall it finds adjacent to the target position.  Defaults to false if 
+not specified.
 
 =====
 is_node_loaded(pos)
@@ -490,11 +457,11 @@ call the usual spawn_tree() functions.  This rerouting exists as a way for
 other mods to hook into plants_lib's tree-growing functions in general,
 perhaps to execute something extra whenever a tree is spawned.
 
-plantslib:generate_tree(pos, treemodel) is called any time a
-tree is spawned at map generation time.  'pos' is the position of the block on
-which the tree is to be placed.  'treemodel' is the standard L-Systems tree
-definition table expected by the spawn_tree() function.  Refer to the 'trunk'
-field in that table to derive the name of the tree being spawned.
+plantslib:generate_tree(pos, treemodel) is called any time a tree is spawned
+at map generation time.  'pos' is the position of the block on which the tree
+is to be placed.  'treemodel' is the standard L-Systems tree definition table
+expected by the spawn_tree() function.  Refer to the 'trunk' field in that
+table to derive the name of the tree being spawned.
 
 plantslib:grow_tree(pos, treemodel) does the same sort of thing whenever a 
 tree is spawned within the abm-based growing code, for example when growing a
diff --git a/plants_lib/init.lua b/plants_lib/init.lua
index dba332b..d41b52b 100644
--- a/plants_lib/init.lua
+++ b/plants_lib/init.lua
@@ -483,7 +483,7 @@ function plantslib:spawn_on_surfaces(sd,sp,sr,sc,ss,sa)
 				  and pos.y >= biome.min_elevation
 				  and pos.y <= biome.max_elevation
 				  then
-					local walldir = plantslib:find_adjacent_wall(p_top, biome.verticals_list)
+					local walldir = plantslib:find_adjacent_wall(p_top, biome.verticals_list, biome.choose_random_wall)
 					if biome.alt_wallnode and walldir then
 						if n_top.name == "air" then
 							minetest.set_node(p_top, { name = biome.alt_wallnode, param2 = walldir })
@@ -555,7 +555,7 @@ function plantslib:grow_plants(opts)
 			local root_node = minetest.get_node({x=pos.x, y=pos.y-options.height_limit, z=pos.z})
 			local walldir = nil
 			if options.need_wall and options.verticals_list then
-				walldir = plantslib:find_adjacent_wall(p_top, options.verticals_list)
+				walldir = plantslib:find_adjacent_wall(p_top, options.verticals_list, biome.choose_random_wall)
 			end
 			if n_top.name == "air" and (not options.need_wall or (options.need_wall and walldir))
 			  then
@@ -612,12 +612,24 @@ end
 -- function to decide if a node has a wall that's in verticals_list{}
 -- returns wall direction of valid node, or nil if invalid.
 
-function plantslib:find_adjacent_wall(pos, verticals)
+function plantslib:find_adjacent_wall(pos, verticals, randomflag)
 	local verts = dump(verticals)
-	if string.find(verts, minetest.get_node({ x=pos.x-1, y=pos.y, z=pos.z   }).name) then return 3 end
-	if string.find(verts, minetest.get_node({ x=pos.x+1, y=pos.y, z=pos.z   }).name) then return 2 end
-	if string.find(verts, minetest.get_node({ x=pos.x  , y=pos.y, z=pos.z-1 }).name) then return 5 end
-	if string.find(verts, minetest.get_node({ x=pos.x  , y=pos.y, z=pos.z+1 }).name) then return 4 end
+	if randomflag then
+		local walltab = {}
+		
+		if string.find(verts, minetest.get_node({ x=pos.x-1, y=pos.y, z=pos.z   }).name) then walltab[#walltab + 1] = 3 end
+		if string.find(verts, minetest.get_node({ x=pos.x+1, y=pos.y, z=pos.z   }).name) then walltab[#walltab + 1] = 2 end
+		if string.find(verts, minetest.get_node({ x=pos.x  , y=pos.y, z=pos.z-1 }).name) then walltab[#walltab + 1] = 5 end
+		if string.find(verts, minetest.get_node({ x=pos.x  , y=pos.y, z=pos.z+1 }).name) then walltab[#walltab + 1] = 4 end
+
+		if #walltab > 0 then return walltab[math.random(1, #walltab)] end
+
+	else
+		if string.find(verts, minetest.get_node({ x=pos.x-1, y=pos.y, z=pos.z   }).name) then return 3 end
+		if string.find(verts, minetest.get_node({ x=pos.x+1, y=pos.y, z=pos.z   }).name) then return 2 end
+		if string.find(verts, minetest.get_node({ x=pos.x  , y=pos.y, z=pos.z-1 }).name) then return 5 end
+		if string.find(verts, minetest.get_node({ x=pos.x  , y=pos.y, z=pos.z+1 }).name) then return 4 end
+	end
 	return nil
 end