For anecdotal evidence about the speed of Oakmont Country Club's greens, host pro Bob Ford recalls familiar scenes around the practice green.

	Chris O'Meara, Associated Press
	Dave Pelz, Phil Mickelson's short-game coach, tests the speed of the seventh green during Mickelson's practice round for the 107th U.S. Open at Oakmont yesterday.

"A guest will put a ball down and look up to say hello," Ford said with devilish glee. "When they look back down, the ball has rolled 30 feet away on its own. It's amazing to see the look on their faces."

For accurate, objective and statistically valid measurements of Oakmont's greased-lightning greens, there is a device called the Stimpmeter that the U.S. Golf Association has implemented as the national standard to record the speed and consistency of putting surfaces.

It is part of Oakmont legend that its greens were the inspiration for the invention of this esoteric piece of equipment. Scales have been invented to put a number on the intensity of earthquakes and hurricanes and tornadoes. Why not something to validate the unbelievable?

During the 1935 Open championship at Oakmont, Edward Stimpson watched from the gallery as the slick greens prevented elite golfers from breaking par. According to one version, he watched in awe as Gene Sarazen putted a ball off the green and into a bunker.

An accomplished golfer in his own right -- he was captain of the Harvard golf team and won the Massachusetts state amateur championship in 1935 -- Stimpson set his analytical mind to invention. He came up with a block of wood, 36 inches long, with a concave ramp that was notched to hold a golf ball. When the device was placed on a flat area of a green and lifted from one end, gravity took over and allowed the ball to roll. The length of the roll provided a numerical reading.

Using money out of his own pocket, Stimpson had 25 such gauges made and donated the devices to the USGA.

It wasn't an overnight sensation, by any means. In fact, the Stimpmeter lay unused in the USGA offices until the 1970s, when a standard was sought. The USGA, the bureau of standards for golf, needed a way to know the speed and consistency of greens for its championship events.

Stimpson's design was tweaked by Frank Thomas, the USGA's senior technical director. The material was changed from wood to extruded aluminum to improve consistency. The ramp was made into a V-shape to eliminate wobbles. And it was christened the Stimpmeter.

The device works with amazing simplicity. On a flat spot on a green, three different balls are rolled in one direction, and with a tape measure, an average distance in feet is calculated. Then the process is repeated in the opposite direction to obtain a second distance. Those two distances are averaged out and a reading is obtained. If, say, the average of the roll is 10 feet, the greens are said to be a 10 on the Stimpmeter.

But there is another twist to the story, again involving Oakmont.

Prior to making the Stimpmeter available to golf course superintendents and course officials in 1978, the USGA took trial measurements at 1,500 golf courses around the country over a two-year trial period.

"The average was 6.5," said Jim Snow, who heads the USGA's greens section. "There were a few at 7, and one or two really fast ones at 8. Then we went to Oakmont on a Wednesday afternoon and got an 11.5, which was more than 3 feet faster than any club we had tested in two years. That was a surprise. We were flabbergasted. We couldn't believe it."

Nowadays, the national average is a 9.5, with some clubs posting readings of 10, 11 or 12, depending on day of the week and growing conditions.

The USGA wants Oakmont's greens at 13 to 13.5 for the Open.

Which brings up another characteristic about Oakmont. The members play on greens that are faster than the speeds set for this tournament. In autumn, when conditions are drier, Oakmont greens register 14 to 15 or higher.

"Yes, it is true. The club has to slow the greens down for the Open," said Mike Davis, senior director of rules and competitions for the USGA. "We really like fast greens, and players see fast greens on a regular basis. They don't see greens like this. Here, the greens are scary fast. They're Oakmont fast."

According to the USGA's Stimpmeter instruction booklet, the tool is not intended for course comparisons, although that may not stop arguments at the 19th hole.

Stimpmeter readings can assist in determining whether a hole location is fair or unfair. The USGA wants championship greens to be fast and uniformly paced, firm but lenient. They should reward well-executed shots while exacting a penalty for less precise shots.

But one more thing about Oakmont. On six of the 18 greens, the surfaces aren't flat enough to get a Stimpmeter reading. The ball just keeps rolling and rolling. So the numbers from the 12 flatter greens are used for the course average.

Any groundskeeper can speed up a green by shaving the grass down to the nub. But scalping comes with the risk of the grass not being able to bounce back, which means a green can die. No matter how low Oakmont's greens are cut, they bounce back.

"Anybody can get really fast greens for a week," Snow said. "I don't believe any club can do it as consistently as Oakmont. I can't imagine faster greens. It's unbelievable how good their greens are."

So what it is about Oakmont?

"That's a good question. I don't know," he said.

One obvious consideration is the grass itself. The surfaces of choice for putting greens are creeping bentgrass in moderate climes or Bermuda grass for hotter areas. Oakmont's greens have been taken over by poa annua, also known as annual bluegrass or pasture grass. The most extraordinary thing about it is how ordinary it is. It's the most common weed in the world.

"You've heard of botanical species that grow anywhere but Antarctica? Well, this stuff grows even on some islands in Antarctica," said Dr. David Huff, professor of plant genetics and turfgrass breeding at Penn State University. "There isn't a place on the face of the earth where poa annua doesn't grow. It's unlike anything else."

It certainly has a mystique about it.

There's probably not a lawn in Western Pennsylvania that isn't infested with poa annua. It's an unstoppable invader that can muscle out creeping bentgrass, and most golf courses try to eradicate it, usually by digging it out by hand.

"Wild and weedy poa annua is the scourge of the golfing industry. It's public enemy No. 1," Huff said.

But there are many variations of it, and the poa annua at Oakmont seems to have undergone a micro-evolution. Over the decades, it has adapted to being cut low. It had a high density of shoots that grow straight up, which means its blades are tightly packed and it isn't grainy. Not only can it take the punishment of having lots of golfers walk on it, it can be cut really short and even withstands heavy rollers, which in turn changes its desirability.

"The beauty of it is that [certain types] can produce super high quality putting greens with super fast putting speeds," Huff said.

Normally, it spits out a lot of seed to insure that new shoots grow annually, but Oakmont Poa annua is a bit freaky. It doesn't produce any seed at all. Instead, all of its energy goes into sustaining itself year after year.

"It's a perennial annual," Huff said paradoxically. "It certainly has a mystique about it."

If you wanted to build a golf green from scratch and wanted to seed it with Oakmont grass, you're out of luck. There are no seeds. Oakmont grows reserve patches of the grass by saving the plugs when the greens are aerated, and then transplanting the plugs elsewhere.

Huff has studied poa annua for 10 years and is receiving grant money from the USGA to see if it's possible to develop seeds for a greens-type plant. Seed production may be three years away.

"We're not out to replace creeping bentgrass," he said. "But if nature is going to supply you with poa annua in such great abundance, then why not nurture it, give it a decent home and turn it into a benefit instead of a bane."

Meanwhile, it's almost a sure bet that a U.S. Open contestant will be muttering about vile weeds after a putt rolls out of control. It may take a Stimpmeter-like invention to measure the frustration levels.