One hundred years ago, the newest greenhouses looked like cathedrals; now, the newest cathedrals look like greenhouses. It was the grand strategy of Victorian aesthetics to “dignify” the crude functionalism of the Industrial Revolution with a healthy dollop of high-church aspiring. Today, through an antithetical – but basically identical – process, we feel compelled to deconsecrate all that is sacred through a vocabulary of increasingly ornamental functionalism.

The Nolen Greenhouses, which recently opened at the New York Botanical Garden, are for once a triumph of real, rather than ornamental, functionalism. Some of the most ambitious such structures ever built, they look, as you might expect, quite like greenhouses. I cannot detect in their endless, modular corridors of steel and tempered glass, or in the ridge and furrow roofs of the 36,000-square-foot interior, the vaguest hint of any impulse beyond utility in conserving energy and caring for plants. From the operable roof to the north-south axis, absolutely every detail of the buildings achieves maximum efficiency. But Nolen Greenhouses, designed by Jan Keane and James Braddock of Mitchell/Giurgola Architects, are a lovely crystalline mirage of buildings.

To mark its inauguration, a delightful exhibition, “Glasshouses: The Architecture of Light and Air,” has opened in the New York Botanical Garden’s library, designed by Robert Gibson early in the last century. The exhibition relates the history of greenhouses from their 17th-century origins to the present.

What is so fascinating about these early structures, aside from their decisive role in the genesis of modern architecture, is that they represented, of necessity, a nearly unique instance of functional design in a culture – the European baroque – that fought against functionalism at every step. In an age when any use of stone, even the most functional, invited a triglyph, a swag, or a guilloche, such flourishes were rarely attempted in the glass and iron that went into making the first greenhouses. The resulting structures at times look disconcertingly modern, even as far back as the 17th century. You see this in an illustration from Richard Bradley’s “New Improvements of Planting and Gardening” of 1718, which depicts a wood-and-brick house for bud propagation, as well as in the primitive orangery depicted in Heinrich Hesse’s “Neue-Garten-Lust” from 1690.

The most famous glass structure of premodern times was Sir Joseph Paxton’s Crystal Palace, the magnificent building. It was completed in London’s Hyde Park in 1851 and burned to the ground over 80 years later. Most New Yorkers, however, probably do not realize that, shortly after the London building was completed, a similar structure arose in New York, in what is now Bryant Park.

In both cases an ornamental, even romantic, effect was achieved more through overall massing than through any vernacular detail. The three tiered London structure could be read as a shimmering glass simulacrum of the Duomo in Milan, its rayonnant facade approximated by the stately striations of the cast-iron skeleton. It even had a barrel-vaulted midsection, doubtless intended to be read as a transept to the nave that made up the rest of the building.

By contrast, the New York structure was an architectural hybrid, a sprawling, centralized arthropod of a building, whose interior dome and series of minarets along the circumference played into the Orientalism of the day by strongly recalling Hagia Sophia in Istanbul. At the same time, along the circumference were endless sequences of blind glass arcades, a central portico and behind it, a glass wall configured to recall the rose window of Notre Dame de Paris.

Half a century later, Lord & Burnham, described in the show as “the biggest and busiest manufacturer of glasshouses in North America,” designed what is now known as the Enid A. Haupt Conservatory, the jewel in the crown of the New York Botanical Garden’s architectural heritage. By the time it was built, in 1910, the full weight of the Beaux Arts aesthetic, as well as the City Beautiful movement, had kicked in. The domed, centralized structure, flanked by two pavilions, looks back to Palladio’s Villa Barbaro Maser and laterally to McKim Mead & White’s nearly contemporary additions to the Metropolitan Museum.

Aroid House, constructed in 1917 and one of the predecessors to the newest construction, was built by Lord & Burnham on the basilican plan. It was a continuous nave whose glass roof, punctuated by two masonry ribs, rises above a red brick base. On either side, an entrance recalled the slightly Dutch aesthetic of the subway station at 72nd Street and Broadway.

The initial effect of the Aroid must have been very different from that of the Nolen Greenhouses that have just opened. The two main components of the latter, joined by a central administrative center, expand in a dizzying abundance of tempered glass that rises around you like the oversized installation art of Lucas Samaras or Yayoi Kusama. Which is to say that, at its most functional, the Nolen inadvertently become supremely ornamental.