(GREAT BARRINGTON, Mass.) – If, as they say, it’s true that the Velvet Underground only sold 1,000 albums in its time, but everyone who bought one formed a rock band, then the same can probably be said for country-rock legend Gram Parsons, who is much more talked about than he was ever heard.

Parsons is something of a spectral presence, or the spiritual godfather, of the entire alt-country movement of the last two decades – bands like Son Volt and Uncle Tupelo — even though the average music listener would be hard put to name one of his songs. Nevertheless, musicians especially love him, and the Berkshires’ own Johnny Irion, who is influenced by plenty of Americana legends, will be paying tribute to Parsons’s musical legacy on Monday,  September 5, at 8 pm, in a special concert at the Castle Street Cafe, where he’ll be joined by Matt Downing and Pete Adams. Admission is free.

“He started this whole cosmic country universe,” said Irion of Parsons recently, “fusing country songs with bluegrass, rock n’ roll, and pop ballads.”

Indeed, Parsons straddled multiple genres, on his own and with bands including the Byrds, the Flying Burrito Brothers, and the International Submarine Band. He was a late addition to the Byrds, and only was connected to the group for one short year in 1968, but it was for the making of the pivotal album, Sweetheart of the Rodeo, which saw the pioneering folk-rock group turning toward country music in a big way.

Parsons went on to record only two solo albums, GP and Grievous Angel, both of which were products of his musical alliance with a then-budding country singer named Emmylou Harris, but he was dead at the young age of 26 (he didn’t even make it to the cosmic 27) of a drug overdose even before his sophomore effort was released.

Parsons is nearly as renowned for his troubled outlook and his substance abuse as he is for his musical vision; while his friendship and musical alliance with Keith Richards is often credited with steering the Rolling Stones in the direction of country music on albums including their landmark Exile on Main Street, Parsons’s behavior was apparently even too much for the notoriously drug-loving Richards, who threw him out of his French villa where he was staying during the recording of Esile.

Irion, who performs on his own and as a duet partner with his wife, Sarah Lee Guthrie, counts himself as one of those who has been influenced by Parsons. “My voice has been compared to Gram’s a lot,” he says, not noting, also, that he even bears a physical resemblance to the baby-faced Parsons. “I thought it’d be fun to play with Matt and Pete and do something local that’s low-key, with good vibes.”

Castle Street Cafe typically presents jazz in its Celestial Bar, but chef-owner Michael Ballon went along with Irion’s suggestion to try something a little different that might appeal to a different crowd.

Irion has been going back and listening to Parsons’s recorded work, which isn’t a lot, frankly. “From his first bluegrass album with the Shilos to the Flying Burrito Brothers, every record holds up,” he says.