Are Bush Killer berries rare? / 3-leaflet and 4-leaflet Bush Killer

Porcelain berry is in the grape family.

Bush killer is also in the grape family.
However, I never see bush killer berries.

I feel like I've seen the flowers bloom, though... And if it's in the grape family, I feel like it should bear fruit like the porcelain berry... Why?

Just when I thought that, I discovered a plant that actually had berries on it.

It's a bush killer, right!?

Since it's in front of someone's house, I can't stand there for too long, but I was surprised because I've never seen them before (maybe I just ignored them even if I had seen them).

However, even though I feel like I've seen bush killer flowers everywhere (I can't observe the flowers much because hornets come around), the berries are only here... Is it a plant that has trouble producing fruit?

When I searched for that, it turns out that many bush killers are "triploids" that cannot produce fruit, and especially in eastern Japan, triploids are common, so it seems berries are rarely seen.

...What is a triploid?

"Triploid" has to do with genes (?), and it seems to be something that has 3 sets of chromosomes. Triploid organisms seem to have difficulty with sexual reproduction. That's why they say that in fruits, triploids are artificially created to make seedless fruits.

Bush killers are often triploids, and even if they don't produce seeds, they seem to propagate well through underground stems.

It is said that those that don't bear fruit are triploids, and bush killers that do bear fruit are diploids.
It seems there are differences between diploids and triploids other than whether they produce fruit; the leaves of triploids are always in sets of 5 small leaves, while diploids have a mix of 3 or 4 leaflets.

Come to think of it, bush killer leaves always look the same, so it's interesting that there are 3-leaflet and 4-leaflet ones.
Since there are berries here, there might be a diploid nearby. I want to pay attention to the leaves too.

So, when I started paying attention to the leaves, I found things everywhere that looked like "Are these 3-leaflet or 4-leaflet ones?"
They might have been eaten by insects, or maybe they aren't actually bush killers...

...And so, although there are no berries, there are many that look like 3-leaflet or 4-leaflet leaves.

Does that mean these bush killers have the ability to bear fruit, but just aren't doing so because the conditions aren't right?
Or maybe if they can propagate through underground stems, there's no need to bear fruit.

I've been watching vines, and I kind of wonder if they don't feel settled when they are crawling on the ground, and if it's easier for them to bear flowers and fruit when they are tangled up in high places...

So, looking at bush killers in slightly higher positions.

Oh, there are berries!
But they are far away!

There were berries nearby too, but they were mostly hidden and there was only one.

In the first place, since bush killer weeds get mowed, maybe it's hard for them to grow to the point of producing seeds. Hornets also come to bush killers, too...

However, since Cayratia japonica also propagates via underground stems, it is said to be persistent, as it grows back even if you try to pull it out completely.
Considering that it might be eaten by herbivores, it might be better for it to snap off rather than being pulled out completely by the roots, allowing the above-ground parts to be eaten while the plant recovers and grows back.

With that said, this was a post about Cayratia japonica berries.

Click here for previous posts featuring Cayratia japonica.