Plants that indicate water

My job takes me all over the place and I meet many people. This week I met a real Monk at a real monastery. The Fathers and Brothers invited me to stay for lunch. They have 2000 or so acres and have had 10k turkeys and raised cows for cheese. You get the picture. Great lunch and conversation to say the least.
So in the middle of lunch one of the monks tells me that he can show me a grass out side that when it shows up water will eventually start to flow or spring forth from the ground there. I stopped chewing and said, WHAT? He said yes. I'll show you. I dropped my fork and said you first...
He showed my the grass and I cut some for keepsake and future reference. I'll try to post it with this text but have been having trouble today attaching photos. I promis ill get one up though.
The grass is oblong in cross section. Very tough dark green. The photos are of grass that has been weed whipped so the tops are frayed.

I mention this because I wonder if others of you have seen or know of water indicating plants. Sub surface water. I have been told that a pine on our property likes wet feet. Any one out there believe they know of true indicator plants?
Jim photo to follow.

Picture attempt

This grass was taken in a Permaculture type area that was in the middle of the Mojave dessert. Just think of the well digging money saved if one could accurately predict sub surface water! This field, Permaculture is at its infancy as Paul in his podcasts says. I believe it is true. We are just beginning to scratch the surface.
That said. What if a group of us here began to document our observations of plants that are unique to otherwise unknown subsurface water. i.e. indicator plants. Find two in an area and maybe triple your chances of water.
If gust is interest in this thread ill get up a photo of the pine that OS supposed to be an indicator.

I look forward to hearing what you have to share.

Jim

Looks like some kind of rush (Juncus spp.) Wetland plant indicator ratings are based on years and years of field work...
http://plants.usda.gov/wetinfo.html
No really an indicator of well digging success, but at least season soil saturation...

The vegetation ecology literature has continued to advance since Bill Mollison left the academy... I particularly appreciate JP Grime
http://scholar.google.com/scholar?q=JP+Grime&btnG=&hl=en&as_sdt=0%2C48

in our area an indicator of water near the surface is cattail rushes, sometimes other rushes as well. You won't necessarily get a flowing well, but you will find water if you dig there.

Paul and Benda,

Great info. This is what I was hoping for. Trees that indicate would be interesting too. Hoping someone may know of some species that tend to have deep roots and need water.

Willows and cottonwoods indicate the presence of water...

yes here it would be willows aspen and alders, also black spruce and cedar