Rita Donahue, Mikhail Baryshnikov, Aaron Loux, Dallas McMurray, Maile Okamura, Amber Star Merkens in Mark Morris Dance Group's "A Wooded Tree." (Tim Summers/Tim Summers)

Mikhail Baryshnikov is dancing.

He is 65.

And so, as a friend asked when I told him the news, what is there to see?

Well. A great joyous appetite, for starters. The former ballet star’s delight in performing — skipping, clowning around, showing off his still-beautiful arabesque — hits you like sunlight at Wednesday’s opening of the Mark Morris Dance Group’s two-week season in Brooklyn. The group is performing four works, two of them world premieres, in a 150-seat theater in its home building. (The run is sold out, but a few tickets are up for bids on eBay.)

The space, a converted studio, is so intimate, you can hear the leather of the dancers’ shoes creak as they pivot and spin. Its humble scale is the perfect frame for an evening focused on the small details of life. Afterward, the dancers mingled with the audience over wine and cookies, Baryshnikov included. In rimless glasses, a dark blue shirt and black jeans, he looked more comfortable schmoozing with his fans than I’ve ever seen him.

Aaron Loux, Mikhail Baryshnikov, Dallas McMurray in Mark Morris Dance Group's "A Wooded Tree." (Stephanie Berger/STEPHANIE BERGER PHOTOGRAPHY. ALL RIGHTS RESERVED.)

Perhaps this was because the role he had just danced was an exceptionally wise and true fit. “A Wooden Tree,” a piece unveiled last fall in Seattle, was accompanied by the crackly recorded vocals of Ivor Cutler, the Scottish poet and humorist who has a 6-year-old’s way with words and an old salt’s attention to life’s frailty (among his songs heard here were “Cockadoodledon’t” and “I Love You but I Don’t Know What I Mean”).

The dance is kooky, charming and very funny, and also a little bit sad, in a way that makes you ache. It leaves you with a strange, mixed-up feeling, though the dancers seem to be having a grand time, and none appears happier than the slim, gray-haired dancer with a distinct lightness in his step.

Baryshnikov has a long and fruitful history with Morris. In 1990, after Baryshnikov left American Ballet Theatre, which he had directed, the two men founded the White Oak Dance Project, a modern-dance repertory group. Morris was a featured choreographer and Baryshnikov its box-office draw. Morris has created many works for his friend, the last one being “The Argument” in 1999; it was a serious piece with dark undertones. Baryshnikov was devastating in it, a little dangerous.

There are flashes of darkness in “A Wooden Tree,” but Morris undermines our expectations. We’re on a planet of eccentric misfits, where Baryshnikov is the benign funny uncle. He is the embodiment of Cutler’s wry wit and — importantly — his wistful, understanding, backward look at his youth.

Nostalgia is in the air even before we hear Cutler grouse on the soundtrack about contemporary music: “I feel that all the old values have gone.” Michael Chybowski’s lighting, superb all evening, is golden and shadowy. The cast of eight is dressed in bulky woolens and argyle socks, as if there’s a duck hunt in the offing. Or do they bear a touch of hipster irony? (Not Baryshnikov; he’s in trim trousers and a proper shirt, though his socks connect him with the others.)

Baryshnikov is fully part of the group, step for step, and there’s a gorgeous amount of bubbly, crisscrossing action here. But vanish into the ensemble? That’s the one trick he can’t do. He makes you watch his every move: the little grapevine step with a smooth, elastic bounce. And the way he glides as he walks, his weight perfectly gathered underneath him.

He has us from the start, well before the moment when he strikes a low arabesque pose on a chair, his leg extended behind him, chest proud and high. He looks like the prow of a ship, cutting through a sea of whipped cream. A couple of the female dancers hold him steady, the way a ballet prince would partner his ballerina — ha-ha! Later, when he whisks one of the women around in a quick waltz — just two or three steps, his hand at her back — the audience seduction is complete.

Was it all canny magic mixed with sentiment, the way an aging star can make you think you’re seeing more than you are? Baryshnikov is a magician — always has been — but his appeal remains aesthetic. He is our Beethoven of the body, his expressive powers no less diminished with time. You see that in the fullness of his arms, their simple, majestic shapes, and in the snappy little jig he dances at the end, shimmying his hips and slapping his hands, playing to the seats as only he can.

As Cutler chants “Little Black Buzzer” in a monotone dee-dee-dee-dit / da-da-da-DAH, and you think of the last living human sending a message to no one, Baryshnikov is curled up on the floor, tapping Morse code onto the seat of a chair with his fingers, with a look that is both focused and faraway. In “I Got No Common Sense” he giddily jiggles every joint like one of those antique jumping-jack toys on a string. In other words, he’s a throwback, a relic. Have all the old values gone, as Cutler lamented? Baryshnikov is the perfect dancer to make us think of what has vanished and is vanishing.

We’ve been waiting a long time to see whether they make dancers like him any more. This program offered an answer: Spencer Ramirez, a Virginia native who trained at Silver Spring’s Maryland Youth Ballet, came to the fore, suggesting a compelling likeness to the famous Russian. He’s a much younger version, obviously, and that is a key part of his charm — to the compact, balanced proportions and close-cropped haircut he shares with Baryshnikov, he adds boyish good looks. Also, charisma.

But it’s mostly Ramirez’s crisp, effortless, gliding way of moving that recalls the older star. It’s no wonder Morris used him in the three other works, including a duet (one of the world premieres) named for him and his partner: “Jenn and Spencer.” In it, the smothered violence between the two finally erupts when she slaps him, sending him spinning. Henry Cowell’s Suite for Violin and Piano, played live as was the case for each piece except “A Wooden Tree,” rumbled like approaching thunder.

This was a heavy, bitter dance in a coarse language I haven’t seen before from Morris. It’s not coldhearted, though. We get a sketch of their past passions. At one point, Jenn Weddel slides down Ramirez’s legs, sniffing him all the way, sniffing even his plumbing. When such intoxicating intimacies corrode, beware the explosion.

But there was velvet, too: Ramirez can slip from one position to another in zero time, no transition. As my companion pointed out, he doesn’t even sweat. Effortless.

By contrast, Weddel conveyed an earthy, substantial weight. As much as women have powerful roles in so many Morris works, on this program they were more often the bad guys. In “Crosswalk,” the second premiere, set to Carl Maria von Weber’s Grand Duo Concertante for Clarinet and Piano in E-flat, two of the three women were hard, clinging obstacles in the smooth cresting and receding rhythms of the 11-man ensemble. There was so much texture and fire in the music, a wild ride with Todd Palmer on clarinet and Colin Fowler on piano. Onstage, a luxurious coolness reigned, except for those flaming females.

In “The Office,” which the company performed in February at George Mason University, you see a whole world come to life and vanish in 30 minutes or so. A woman carrying a clipboard is all cold, bureaucratic evil, escorting one of the dancers into the wings at the end of each movement of Dvorak’s Bagatelles for Two Violins, Cello and Harmonium, Op. 47. She is unmoved by the rich, spirited folk dancing. As he did with Baryshnikov, Morris undermines our expectations throughout this program: The women he puts in leadership positions are not the sensitive, feeling ones.

But the other dancers carry on regardless. This is significant. “We keep on singing because we’re optimists,” says Cutler in his frail, jagged voice, near the end of “A Wooden Tree.” Add “dancing” to “singing,” and I believe you have the Morris credo. Baryshnikov gave it further power. Aging, decline and eventually death, too, will come. But until then, there is dancing.