“Too Old to Rock and Roll, Too Young to Die”? Jethro Tull’s Ian Anderson came up with that notion when he was all of 27. But today, at a spry 71, the iconic flute-playing (still on one leg!) Pied Piper of Progressive Rock remains very much in the game. On Saturday, his 50th anniversary celebration of the band packed the Mann Center shed — with a nice spillover onto terrace seats, too — for a nearly two hour, 17-song session that delighted the mostly boomer-generation crowd.

The "party pooping" Anderson has claimed he's not one for nostalgia and still churns out the occasional new album like 2014's cranky Homo Erraticus and 2017's The String Quartets.  Yet, he opted to concentrate on the first, most successful decade of the band's work — that eclectic mishmash of blues (like the evening's early bird special "My Sunday Feeling" and "New Day Yesterday"), crunchy rock riffage (show-closing "Locomotive Breath" scorched by guitarist Florian Opahle) and several representations of back-to-our-agrarian-roots English folk ("Heavy Horses," "Songs From the Wood," "Farm on the Freeway") that have been key to the band since they named themselves after the inventor of the automatic seed-planting machine.

Less represented were other branches of the Tull tree of life like classical and jazz, though of course they had to do the essential mash-up of Johann Sebastian Bach and Rahsaan Roland Kirk that is "Bouree." Also given short shrift were those East Asian flavors that Anderson likes to play. I was really craving a taste of the raga-beat "Fat Man," likewise "Nothing is Easy" and "Living the Past."

Still there were enough samples from all columns in this eclectic musical menu to remind anew how Tull set the “anything goes” tone for the free-form rock radio stations of their era (like WMMR, also celebrating its 50th birthday with an alumni bash this month) and all the listeners who fell under its sway. Given the band’s liberating impact, it’s truly a crime that Jethro Tull hasn’t been inducted into the Rock and Roll Hall of Fame.

Always a great showman, Ian Anderson upped the ante of his once-innovative "Tullavision," a closed-circuit video system this time with a well-synchronized and artful rear projection display that let the band play along with youthful versions of themselves and their predecessors, as well as with ringers like Icelandic singer-fiddler Unnur Birna Björnsdóttir and actor/musician Ryan O'Donnell — who hit all the high notes on "Aqualung," now beyond Anderson's reach. The front man also had keyboardist John O'Hara and bass player David Goodier handle some of the high harmony notes, on songs the studio-obsessive Anderson originally overdubbed himself. But Anderson's odd (for rock) baritone voice is so distinctive he can't really have others sing in unison with him as cover-ups, he recently shared in a chat, as contemporaries like Brian Wilson, Billy Joel, and Paul McCartney often do.

Happily, the Tull-acaster is blowing his flute and harmonica with as much strength and skill as ever, which helps explain why instrumentals played such a big (maybe exaggerated) part of the anniversary play list — from "Dharma for One"  (with a big drum solo by Scott Hammond ) to a left-field "medieval folk rock" entry credited to King Henry VIII.

Also dressing up the video screen and adding to the festive celebration were invited band alumni (Jeffrey Hammond-Hammond, Mick Abrahams, John Evans) and noted fans (like Joe Bonamassa and Black Sabbath's Tony Iommi) to introduce their favorite Tull tunes.

Oddly missing in action was the band's last departing original, guitarist Martin Barre, who left in a 2011 breakup, but has since contributed anecdotes to deluxe reissues of Jethro Tull albums. There was also no reintroduction of the group's longtime arranger and sometime keyboardist formerly known as David Palmer. Now she's Dee Palmer.