Sies Marjan designer Sander Lak emerged as a leading voice of New York Fashion Week on Saturday, showing a powerful collection with the steel and concrete canopy of Midtown Manhattan as a backdrop.

The theme was the countryside, or more specifically “Countryside, the Future,” Dutch architect Rem Koolhaas’ exhibition opening next month at the Guggenheim Museum, which Sies Marjan is partially sponsoring.

“This is my Dutch moment,” said the designer, about working for more than a year with fellow Dutchman Koolhaas, and having access to the exhibition materials for inspiration. “The exhibition is really a research project spanning from the days of Marie Antoinette pretending to be a farmer…to the future of how, if there is no sunshine, we still grow vegetables,” Lak said in a nod to the climate crisis and battling the changing elements.

That translated on the runway into a thoughtful exploration of pastoral elegance and layered workwear inspired by everything “from 15th-century Dutch farmers to the Eighties upstate New York leisure lifestyle,” the designer said, explaining how he collaborated with artisans on some rather revolutionary organic effects, dyeing fabrics by pressing foliage into them, for example.

It made for some gorgeous, modern classics, including the gold-leafed sheath that opened the show, and the black lace one that followed, worn over a glimmering gold shirt and pants. Utility pieces ranged from a gem of a trench with a linear design resembling a root system, to oversize shirts and trousers in natural hues worn with wooden clogs.

Fold-over waistband skirts and trousers paired with safety-orange fisherman sweaters looked great, as did quirky pinafore dresses with cargo pocket belts. And a softly tailored wool pants suit with a pressed leaf pattern was timelessly elegant.

Sies Marjan is becoming a go-to for sophisticated leather (and leather-like glossy vinyl) wardrobing. Lak leaned into the category as a signature this season with several winning pieces, ranging from a soft-as-butter full skirt, worn with chunky wool cardigan and clogs that brought to mind Diane Keaton in “Baby Boom,” to a futuristic glossy patent poncho the color of sunshine, which certainly shined down on Sander this season.