McGarrigles’ Insight Improves With Age

“This song is about life,” Anna McGarrigle deadpanned at the Ash Grove on Saturday, drawing chuckles from everyone in the room, including younger sister Kate, her musical partner. “It’s called ‘Why Must We Live?’ ”

The reason for the laughs was that the song--the title track from the French-Canadian duo’s new album, “Matapedia”--followed two songs about death, including a new one titled “Why Must We Die?” The unspoken punch line is that all the McGarrigles’ songs are about life and have been for the nearly 25 years that they’ve been folk-pop cult heroines.

It’s just that now, in midlife, mortality is increasingly part of their vitality. But in their low-key way, they offer it with all the fervor and immediacy that their younger countrywoman Alanis Morissette does with her generation’s concerns.

Time and experience, though, have only enriched their art, both in the vividness of their personal lyrics and the rustic colors of their voices and music, with their piano, guitars, banjo and accordion supported nimbly Saturday by Joel Zifkin’s fiddle and Michel Pepin’s bass and electric guitar.

At least two members of Morissette’s generation get the connection. Siblings Rufus and Martha Wainwright were given the stage for two songs Saturday and showed not only remarkable harmonies, but also strikingly poetic songwriting talent. Of course, they have a head start--they’re Kate’s kids from her ‘70s marriage to singer-songwriter Loudon Wainwright.

* Kate and Anna McGarrigle play tonight at the Ash Grove, 250 Santa Monica Pier, Santa Monica, (310) 656-8500, 8:30 p.m., $20.