Leaves of Three…

Congratulations to everyone who chose “Photo E” in the Poison Ivy quiz – you will be rewarded by many rash-free camping, hiking, hunting, and canoeing trips!  For the other 37% of you… here is some more information that might help you in the future.

First off, what were the other photos of?

Photo A: Hog Peanut.  This is a very common plant in woodlands  – it twines around other plants, sometimes up trees, and often along the ground, creating a carpet of three-leaved plants.  As a legume, its growth is characteristic of others in the pea or bean family – it has three symmetrical leaves, and fine curly tendrils at the growing end of the plant (maybe like the peas in your garden).  It gets the name “hog peanut” from its tuber-like root that is edible… if you bother to dig up enough of them to make a meal!

Photo B: Raspberry.  A couple of you guessed this one – you’ll be missing out on some tasty treats this summer!  Raspberries and blackberries often look like they have three leaves on a branch, sometimes 5, sometimes more.  The leaves have toothed or serrated edges, though, the leaves are usually somewhat fuzzy, and the veins are very clear.  The stalks usually have hairs and/or thorns on them, so you probably don’t want to get in a thicket of them without shorts on.  The flowers are white, and the berries… well, they look like raspberries (in this case black raspberries)!  The plant grows on long canes that together look like a bush, often between head- and waist-high, though the young stalks are shorter and especially blackberries can grow well above my head!

Photo C: Trillium.  This is a woodland plant that has a big, showy, white flower in the early spring – there are many different species throughout the Unites States; this one is a Large-flowered Trililum (Trillium grandiflorum).  The “tri-” in its name refers to the fact that the flower has three petals and the plant has… you guessed it… 3 leaves!  Its leaves are large like Poison Ivy’s can be, and the shape of the leaves is not always perfectly symmetrical.  However, a few things set it apart: 1) if it is blooming, it will be obvious! Even if it is done blooming, you may be able to see where the flower came from – right in the middle of those leaves.  2) Trillium, being in the Lily family, has a few long veins, rather than many shorter veins off of a central mid-rib.  3) The leaves of most trilliums rarely appear glossy.  4) Each trillium plant is a stand-alone – just a stalk with three leaves at the top, and a flower.  There may be several plants in a patch, but each one is distinct.  While it is possible to see Poison Ivy with just three leaves and a stalk, it is more common to see that grouping as part of a larger plant.  5) Trilliums are herbaceous – they wilt and die back after a few months of growth; Poison Ivy has woody stems and thus the stalks persist even when leaves are not present.

Photo D: White Oak sapling.  No one guessed this, but to me it can be a tricky look-alike.  It has a woody stem, like PI. The leaves of young white oaks, in their first year of growth. can be of varying sizes, and may or may not be symmetrical, though all of the leaves have at least some waviness to them.  A clue to this one is that you can see even younger leaves starting to grow, and if you look around you should be able to find one with a very characteristic “oak” leaf.  Also, the stem is much more robust than that of Poison Ivy, because it is the start of the trunk that will one day support the “might oak.”

Photo E: POISON IVY!!  This really is Poison Ivy.  Note a few characteristic features: 1) Glossy leaves – that is the oil that is going to cause the nasty rash!  2) A-symmetrical leaves – often one half of the leaf has a smooth edge, while the other half has a couple serrations, teeth, or waves in it.  On larger plants the leaves will sometimes look like a mitten – just a thumb and a finger showing, with the rest smooth.  If there are several plants visible in one location (which there almost always are), it is likely that all of the leaves will look a little bit different.  These leaves are the best way to ID poison ivy!  3) Poison Ivy has woody stems, but that is sometimes hard to tell.  It can grow like a small shrub, like an individual plant, or like a vine, up a tree or neighboring branch.  It doesn’t have to look like a vine, though.  4) Poison Ivy grows in a “rhizominous colony,” meaning that all of the plants in one area are likely connected by the same roots – this is what makes it grow up trees, and spread quickly once established.  5) As I showed in the previous post, PI has white berries and flowers – but you may not get close enough to be able to see that!  6)  As I also mention, PI, though characteristically found in the woods, can also grow in open fields and riparian areas.  Here in Wisconsin, our “western poison ivy” grows in open prairies, and the “eastern poison ivy” has done a great job of colonizing the floodplains of the major rivers.

Photo F: Virginia Creeper.  This is a common vine that grows in the woods.  It has a woody stem, and you can see it twining around many of the trees around you, I’m sure.  But…it has 5 leaves!  So it is clearly not Poison Ivy.  You were all smart enough to know that, and no one chose it in the quiz!  However, I know some very intelligent people who have spent their whole lives avoiding the harmless Virginia Creeper because they thought it was the dreaded PI!

Photo G: Desmodium glutinosum.  This plant has a common name, too, listed in my book as Cluster-Leaf (or Pointed) Tick-trefoil.  It is a relative of the Tick-trefoils that grow in western prairies, but this one grows in the woods.  It has somewhat irregularly-shaped leaves, in groups of three (it’s another legume – they’re tricky!), but it is yet another harmless wildflower growing around us.  A couple things that set it apart from Poison Ivy are: 1) the flowers grow on a long stalk coming up out of the center of the plant; 2) While it appears that the leaves are in groups of three, those are actually the leaflets – there are 3 leaves on the plant, but each one consists of three groups of leaflets, emanating from the central stalk.  If you can see this pattern, it’s a good bet it’s not PI; 3) This plant usually grows singly, not in large bunches, so the above pattern should be easy to discern.

Did you find any Poison Ivy this weekend?  Or avoid any near misses?!  Have more tips for identifying Poison Ivy in the wild, or tricks for healing the rash once you’ve acquired it?


Leave a Reply

Fill in your details below or click an icon to log in:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out / Change )

Twitter picture

You are commenting using your Twitter account. Log Out / Change )

Facebook photo

You are commenting using your Facebook account. Log Out / Change )

Google+ photo

You are commenting using your Google+ account. Log Out / Change )

Connecting to %s