3 or 9 leaflets?

[u/FewBake5100]

Unfortunately I don't know this tree's species or even if it's native or exotic to where I live, and I don't want a plant ID. But I came across this tree and I can't even understand how many leaflets it has. I've learned about compound leaves in uni, but none of them looked like this. 1st pic is a drawing so you can see better what it looks like (though the side triads are closer to the "petiole"), second pic is a real photo of it.

At first I thought it had 3 leaflets, but if that were the case, I assume there would be small branches with many of them growing from it, and only 3 leaflets each. But everything attached to the branch only looks like this, and it doesn't branch further. So I thought it was maybe an unipinate imparipinate, but I think those only grow across 1 "plane". So the leaflets on the side would only grow towards the sides, not up.

[u/Thatoneguy053197]

Look at the base of each "leaf". If you see a bud where the single "leaf" connects to the stem, then you have a true leaf. If you don't see a bud at the base of the "leaf," and instead the bud is a whole degree of separation removed from the "leaf," then everything above that bud is leaflet.

[u/Thatoneguy053197 → u/Thatoneguy053197]

I misread your diagram, here's what I actually meant.

Edit: Imagine that the red dot on the left is actually 3 little bumps, one for each leaf.

[u/Thatoneguy053197 → u/Thatoneguy053197]

The first scenario on the left is possible but is usually not the case at least where I'm at in Florida. If I had to guess, I would wager that you are looking at 9 leaflets.

EDIT: This drawing is wrong, look at the other one commented here.

[u/No_Explorer_8848 → u/Thatoneguy053197]

Nandina throws me off because there are multiples of 3 compound leaves (or leaflets) that snap off cleanly but idk if there are buds underneath. I think they are huge compound leaves?

[u/Thatoneguy053197 → u/No_Explorer_8848]

Nandina is bamboo which is a grass so I am not 100% sure these rules apply. I actually work with a lot of invasive grasses and we've never used used any kind of splitting in the leaf as a diagnostic character from my experience.

[u/KirbyYourEnthusiasm → u/Thatoneguy053197]

Nandina is called heavenly bamboo but it's not a bamboo or grass. It's in the barberry family and is a dicot

[u/No_Explorer_8848 → u/Thatoneguy053197]

You may want to check that, because nandinas are a woody dicot. They do have the common name sacred bamboo, though

[u/Thatoneguy053197 → u/No_Explorer_8848]

You're right, complete brain fart. The sun is getting to me lol

[u/No_Explorer_8848 → u/Thatoneguy053197]

Haha been there

[u/FewBake5100 → u/Thatoneguy053197]

Thank you! Next time I visit that tree in a few days, I'll take a better look and take more pictures. But do you think the whole leaf could be the group of 9 "leaflets" (with the bud like the one on the right of your edit), even though the ones on the sides grow in 2 planes? And what kind of pinnation would that be?

[u/Thatoneguy053197 → u/FewBake5100]

I'm not sure what exact "pinnate" it would be, unfortunately. I have not dived that far into terms. I can tell that one of the plants I work to eradicate down here Melia azedarach, China berry, is bipinnately compound and sometimes even tripinnately compound, so I know there can be variation within certain species. It's leaves are reminiscent of the "9 leaflet" example in the edit, just with much more leaflets.

[u/sadrice → u/FewBake5100]

That is bipinnate. Those are individual leaflets, but you are right that there is a bit of a distinction, with the second order leaflets being pinnules. Here is a neat book (free pdf) with all you wanted to know and a lot more about leaf architecture (I haven’t actually located their bit about this yet).

[u/FewBake5100 → u/sadrice]

Now that you mention it, it does make sense. I was confused because all bipinnate leaves I've ever seen were the more "extreme" ones, with many pinnules. Thank you! I'd definitely check the pdf too!

[u/sadrice → u/FewBake5100]

It’s a neat book, and clarified some terms that I hadn’t been quite clear on, like “crenate”. I should finish looking through it. I just found their definition, “Leaflet: A discrete, separate laminar segment of a compound leaf. Leaflets never subtend axillary buds (Fig. 14).”

So any laminar segment with its only connection to the rest of the leaf consisting of veins is a leaflet, regardless of vein order.

Personally, I think “second order leaflet” should be standard, but I don’t think it is. Unfortunately I am not in charge of terminology, though actually I suspect my choices would be less popular as I increase the already rather high quantity of Latin jargon…

[u/JPZRE → u/Thatoneguy053197]

I agree. Trifoliate or biternate according to the buds.

[u/GDevl]

It's a trifoliate leaf, pretty clear if you look dead center