# How would geometric leaves and flower petals evolve?

## How would a plant grow leaves and flowers that are square and/or geometrically shaped?

Outside of being restricted by external forces like growing in a tight space, how could my plant species grow petals and leaves that are shaped like squares, or triangles, or other geometric shapes?
I'd prefer if they were as exact as possible. However, I know that nature finds it very difficult making precise patterns and angles such as these.

I specifically mean as straight edges and sharp corners as a Minecraft flower or something. I'm less concerned of why they might evolve this, as it wouldn't give much - if any - benefit compared to rounder leaves. Just a little idea that I thought was interesting.

• What does geometrically shaped mean? What is a non geometric shape? Of you want arbitrary shaped leaves in world jut let it be so. As written this looks more like an idle question than like you have a specific world building problem you want help with. Commented May 18 at 4:28
• @sphennings I've considered trying to accomplish this in the past and it recently came up again. 'Geometrically shaped' is outlined in the question's description -- something like a square or a triangle. The question is asking how leaf shape can differ, and how specifically shaped I can make it while keeping it science-based. It isn't an 'idle question' -- nearly all questions on this site would be considered 'idle questions' given this reasoning. Commented May 18 at 4:35
• There's a lot of highly-geometric plants in reality, just do some image searches...some of them are in the form of square flowers and plants. Commented May 20 at 15:39
• May I suggest a change of wording. All leaves are geometric, but what you're looking for are leaves in the shapes of a polygon. Commented May 22 at 3:28

These Plants evolved in an environment of extreme competition for sunlight, and growing a completely opaque canopy became their "weapon" of choice. They would grow a perfectly flat, umbrella-like crowns and block all the sunlight, killing the competition underneath.

At first, these plants had normal drop shaped leaves, but those would capture sunlight imperfectly. Over time, their leaves grew more lozenge shaped, so they could mesh better with one another. From there some sub species speciated to have square leaves, while some grew perfectly triangular ones. A few rarer species evolved perfectly hexagonal leaves.

Time passed, and these leaves became so perfectly shaped (perfect angles, straight lines etc) that when their edges touched they would not only block nearly all sunlight, but capture most water too, and funnel it towards their own trunk. The space between the leaf edges was just too narrow for water to seep through, and acted like a capillary grid instead.

This presented one problem though: a perfect grid of leaves made it impossible for the plant's own flowers to bloom through, without disrupting the grid. It caused the plants to grow flowers with petal shapes complementary to the leaves: for example, the Square-leaf Tree evolved flowers with right-triangle petals, that would perfectly fit in into a square grid once opened.

"Shape wars". Of course, since plants compete, this presented a problem for them. When a Triangle-leaf and Square-Leaf plant grow side by side, their crowns would disrupt each other's grids, since a perfect triangle and a perfect square cannot align. This intense competition would cause both to evolve new weapons: like square leaves that are exactly 1/2 of the regular square leaf, but can be inserted into a triangular leaf configuration to disrupt it, or a very long and narrow triangular leaf that can "cut into" a square grid.

Some plants even managed to grow a form of symbiotism out of it. For example the Square Inch Leaf plant and the Two-inch Rectangle Leaf plant mesh with each other perfectly and share water. On swamps and ponds, there are entire symbiotic colonies of Hexagon floaters that mesh perfectly together, and can even rotate and reconfigure to defeat their non-hexagonal "enemies".

Some of the hardiest trees take it a step further. They evolved to fold their leaves into cubes made of 8 leaves each. The cubes would then harden into a dense, perfectly cubic nutshell with a seed inside. This "seed box" would be extremely durable, because it evolved to sit and wait on the forest floor for decades, if not centuries, until some breach in the canopy would allow sunlight and water in, thus allowing it to sprout.

This means that the dead, dark, dry forest floor would be littered with billions of wooden boxes (some no bigger than a matchbox, some the size of a shipping crate!) The strange fungi and lichens of the forest floor would thus evolve into angular sheets that could grow between and around these cubes. Animals, in turn, would evolve to utilize the cubical wooden spaces, turning into "Jack-in -The-Box" like creatures, crawling rectangular sheets, or even living forlifts.

In effect, you have a whole ecosystem of enforced straight lines and angles, where squares and cubes reign supreme, and triangles aggressively try to fill niches.

“I'm less concerned of why they might evolve this” … Unfortunately, with evolution, how is why. Why does geometric leaves benefit seeding the next generation? The only idea I’ve been able to brainstorm is bird mating rituals. Birds frequently build very precise stages and nests for attracting a mate. If you get a bird that starts off placing a layer of leaves to form a bed, over generations, the species might become increasingly picky about the layout of those leaves. So they only nest in trees that provide such leaves. Make the birds very territorial such that they fight off any bugs that walk on the bark of their tree — but bugs on flowers are fine. Now the birds provide a defense for the tree, which means more of the tree’s flowers survive to spread seeds into the next generation. Trees that attract more of these birds are the trees that have the most geometric leaves that fit the birds’ tiling patterns. Over a couple hundred generations, geometric leaves dominate.

If we assumed that there were evolutionary forces selecting for plants with geometric leaves, whether they be triangular, square, pentagonal, hexagonal or whatever, as long as it's consistent for each species, then the plants will evolve leaves that are very close to those shapes.

We don't need to know how they do it... just that genes that produce the selected-for shape will be preferred over genes that don't produce the right shape. They probably won't be precisely the mathematical shape desired, but they will probably be visually close enough to that shape that it doesn't matter unless someone goes and measures it.

How many people can say what biochemical processes lead to the shape of real-world leaves... and how many would be interested?

• There are many shapes naturally occurring in nature. Spiral shells and hexagonal honeycomb. Some have specific reasons, some less so. Why not square honeycombs? It just happens that way. Commented May 22 at 20:22

Rock Camouflage

The plants camouflage with rocks.

You have to come up with dramatic long-term geological history. For example, at some point the underlying ground had volcanic fissures that made the rocks extremely geometric. Some natural examples are gypsum crystalline caves or basalt formations. Tectonic plates- Maybe it was the coast of an old ocean?

Then it dried up and got arid. The only plant life that grew were succulents. These succulents retain water for long periods of time making them attractive to foraging animals, so they developed a unique evolutionary strategy to survive.It could be a mountain goat or something, or a bird pecking at these to get at the moisture, well anyways the plants have adopted a survival strategy like the lithop (cactus seeds) or 'living stones' from real life Africa. Except these ones are very rectangular or triangle shaped, whatever works in your story.