are there any sprouts or eyes is the technical term they may be purple, white, green, its a thick shoot. If you see one of these when you put the tuber or bark :o) in the pot make sure the sprout is facing up. if you dont see a sprout i'd just put it in and see what happens. make sure it is in full sun and make sure it has enough water but not to much. I"m not an expert on planting in pots so someone else might have a better opinion. good luck!
Carrie

It shouldn't be shriveled, more like the firmness of a potato. Try misting it with water to plump it back up. The eyes form on the piece of stem that is attached to the tuber.
I started my tubers in pots wide enough to accomadate the tuber, laying the tuber on top of the soil. And learned the hard way that too much water will rot them fast !!

I posted a photo in the Dahlia gallery that shows eyes.

Thanks for your replies...I have posted photos of my dahlia tuber. I cannot identify the parts. I know the photos are not that clear but hopefully the experts will identify them. There are 2 photos in the link I pasted below. Please have a look. Also I could not identify any 'eyes'. I am thinking the 'sprout' is the thick portion that looks like a stem that has been cut off..(the top left end of the photo) The whole thing is dried and brown in color...

Here is a link that might be useful: yahoo photos - dahlia tuber

DAZED, It's really hard for me to see from a photo but I'm taking my best non expert guess as follows: Granny and Dapper also gave good advice- you have nothing to lose by planting!
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The long red circle is my guess for a shoot. If it is hard and brown like other stringy roots or stem material, then it is not a shoot, but a root or small old stem. A shoot would be very tender pale green or white, sometimes purplish. It will look very different from the brown dry tuber/stem material.
The little red circle MIGHT be an eye coming off the upright part, assuming that upright part is a stem.

The dark green tuber looks reasonably healthy and like it might support the growth of either of the red circles to go on to give you a plant.

The lighter green is either an old stem with a possible eye (red circle) also possible eye swellings in yellow circles or a tuber/part of a tuber. I am going with stem though.

The hot pink is self explanatory- dessicated, dried out, will never recover and I would cut it off where the purple slash mark is. Allow that cut to dry a couple hours before planting.

If I were you, I'd plant it exactly as you have it photographed here in a pot or ground so the tippy top is covered with 1-2 inches of soil. That will allow heat to work on that stem or eyes faster and you can fill in the remaining 2 inches of the hole as it grows up out of the dirt(hopefully.) Use slightly moistened soil, in full sun and give it two-three weeks to see if it sends out something green. You might be surprised yet!

The unlabelled, remaining brown blob to the left of the purple slash mark could be a stem, but I'm guessing more likely a broken off tuber in fair shape, not too dried out, not showing discoloration of rot (darker brown or yucky green) and because of the dried roots coming off of it.
Those are my guesses from the photo. I have enough trouble in person looking at the same clumps over and over for weeks, til I get sick of them and can't see a damnable thing that looks like life and lob them into the woods LOL or toss in compost.
Good luck, give it a whirl.

Thank you all: Dapper, GrannyMarsh, Poochella for your very valuable advice. I don't know where I could find better!

Poochella--Its incredible how you were able to clarify everything to me. I have a very good idea now. The markings on the photo was an excellent idea and you have literally walked me through it. As per your advice, I am going to slash the 'unlabelled brown blob' at the point where you drew in the purple slash. I hope others on the forum will find this post as useful as I did. Thank you.

Of course, I will keep you all posted on any progress of the tuber. Have a great day!

I hope you are going to slash the one labelled TOAST, not the unlabelled one pointing nearly straight out at the viewer.
Hope it grows for you, and please keep us posted!

Sorry about that..I read my post again. I meant to say that I was going to slash off the part labelled 'toast' (which I did) and not the unlabelled brown blob which is still intact. I will be putting it into a pot in the evening.. Will keep you all posted.