Architects know and use the word fenestrate; it stands for the arrangement of windows in a building. Everything from pointy or goth-like to typical rectangles or squares, and the imitations of nature with Antoni Gaudi's glorious architectural buildings in Spain (arching and irregular). The most famous Gaudi creation is Casa Batilo, which was considered an eye-sore when it was built, now a destination for anyone interested in architecture.
In the plant world, the well-known Swiss cheese plant or Monstera adansonii has leaves that are perforated with tear-drop shaped holes. Popular in the '70's and possibly more so now, it is not overly expensive or rare, but a good example of fenestration in plants. A tropical vine, native to Central and South America, of the Araceae family, related to philodendron.
A similar species is Monstera obliqua which has even larger leaf holes, often referred to as more holes than leaf, the connecting green parts can become thread thin.
There is little doubt that the gardener will confuse the two since the latter species is neither readily available nor inexpensive. Searching online will bring up many sources for this coveted plant, the most popular is simply called Peru, I'm guessing a special selection with more fenestration. Not easy to grow, to keep this Swiss cheese plant happy it requires 80-90 degrees Fahrenheit and humidity levels above 90 percent (terrarium environment). With its limited leaf surface, the growth rate is barely a crawl, another reason for the hefty prices. The difference in value of M. obliqua to M. adansonii is easily one hundred dollars higher just for an unrooted leaf node. For a fully rooted cutting in a pot the price jumps to a thousand dollars for one small Monstera obliqua plant. Of the 45 or so species of monstera, there are others that produce windows in the leaves. Monstera deliciosa (named after its tasty fruit or breadfruit) is well known, a common houseplant but a very large vine when found growing in the wild.
Curiosity got the best of me when it came to understanding what role the leaf holes play. There are a couple of reasons and if you really think about it, I'm sure you will come up with a few theories. Since these inhabit tropical rainforests, they compete with many large leafed plants, a lot of rain, and intense sunlight. As vines, the early stages might not show signs of fenestration, better to grow with a larger leaf surface to photosynthesize under the canopy of big leaves, fenestration becomes more pronounced as they grow and age (reach sunlight). The holes allow sunlight to reach their vining trunk and also to let rain in to soak the arial roots which anchor to any support they climb. Secondly the winds, particularly hurricanes, will be less likely to knock them off their perch, instead will blow through. Imagine the years of evolution it took for that brilliant que?! As a botanist searching for the most fenestration, I suspect that a high elevation (more wind) might be home to plants that are a bit holier, like places in Peru?
Add variegation and the price tag skyrockets to unimaginable heights. A Monstera adansonii (the common Swiss cheese plant) with variegated leaves can easily run over $1,000. A Monstera deliciosa 'Variegata' could set you back $6,000. to $10,000.! And I might add that people are buying them, it's the "in" thing.
There is also fenestration in succulent plants and an entire genus known as Fenestraria. In this case the succulent parts have windows that are under the surface which open to let in more light, or close to do the opposite. Common house plants like baby toes and string of pearls do just that. In the string of pearls, the windows are elliptic or eye shaped, running down the side of each round pearl.
In the world of odd horticultural terms, this is just another that ranks with guttation, allelopathy, and stratification, all worthy of exploration.
