Helianthus crunch session

Yesterday's botany bender/blast/outing was at Somme Prairie Grove.  I learned something horrible--there are actually four species (at least) of woodland sunflower in the Chicago region, not just Helianthus divaricatus.  I suppose I knew in the back of my mind that these three others--H. strumosus, H. decapetalus, and H. hirsutus--existed, but I figured that since they are distinct species, I would recognize them as being different if I ever saw them.  That's pretty much wrong--at first glance, they all look basically the same.  Even at a second glance, they look basically the same (and I'm still not so sure that they're not actually one species with a wide range of variation).  Luckily, all four "species" exist at Somme Prairie Grove, and site steward Stephen decided to tackle them, with about ten different botanical keys as backup.  The distinctions between them boil down to stem roughness and petiole length/leaf dimension:

1.  H. hirsutus is immediately distinguishable from the others because it is the only one that is rough/hairy all the way down to the bottom of the stem.  They all are (or may be) hairy near the top, but it's the bottom 2/3 that counts.  Unfortunately, it seems that the hairs might sometimes fall off the stem later in the season (of course they would, those little bastards).  In this case, you can tell that they used to be there because there are dark blemishes on the stem.  The leaves have very short or no petioles:

2.  H. divaricatus is the only other one with very short or no petioles, but it is smooth lower down on the stem (can't possibly show the lack of hairiness, but here are the petioles):

3.  H. decapetalus is also smooth lower down on the stem, but has long petioles, often more than 3cm long.  The leaf is generally wide and ovate, less than 3x as long as broad:

It can often be confused with Heliopsis helianthoides...oh, who am I kidding?  They all could, but especially this one because of the wide leaves.  The trick is looking at the bracts under the inflorescence...they're pointy in all Helianthuses (Helianthi?), but rounded or blunt in Heliopsis:

 This is a Helianthus.  Who knows which one.

This is Heliopsis.  Ta-da!

Also, Heliopsis has toothier leaves:

4.  H. strumosus is what they call the "wastebasket" species...it is so variable, that if you can't figure out what species you have, just assume it's H. strumosus.  It is also smooth-stemmed down to the bottom with long petioles, like H. decapetalus, but the leaves are longer and narrower (>3x as long as wide) and petioles are slightly shorter (<3cm) and the leaf tends to taper down to a winged petiole like this:

But not all of the ones that we saw tapered like that, so it's not a definite characteristic.  The photo below shows the allegedly "longer, narrower" leaves.  Nothing you'd ever notice from a galloping horse. 

Lord a-mighty!  Now that we've strained our brains, let's just look at some pretty pictures:

 Agrostis perennans, thin grass.  I've probably walked by this a thousand times thinking it was redtop.

 Brachyeletrum erectum, long-awned wood grass.

 Cirsium altissimum, tall thistle.  Whenever I try to take a picture of the whole plant to show how tall it is, it always turns out like crap.  Backlit and muddled by oak trees in the background.

 Elymus riparius!  I'm finally nailing down these ryes.

 We also learned the difference between tall & late bonesets.  This is Eupatorium altissimum (tall).  Its leaves are long and narrow, and the plant is slightly fuzzy and gray-tinged all over.

 (Even the flowers are fuzzy.)

 This is the leaf of E. serotinum (late boneset).  It's toothier and more egg-shaped.

 Its flowers are sharper-looking and not fuzzy.

 This is allegedly a hybrid between cream and bottle gentians.  Bottle gentian generally blooms much later than this, but it appears to have lent its blue tinge to the cream gentian.

 Hedeoma pulgeoides, pennyroyal, in gorgeous full bloom.  Look at those itty-bitty flowers!  This is one of those plants most people probably just walk right past, because it's tiny and doesn't look like much.

 A-ha.  This is how you can tell Indian grass before it flowers--this distinctive brown ligule that clasps the stem.  I think the narrowing of the leaf blade is also an indicator.

And finally, the state-threatened Tomanthera auriculata, earleaf false foxglove.  The ears are those pointy things on the sides of the leaves.