Not sure what all you got going on there.. but those really long pointy leaves aren't marjoram. If you put out/bring in your pots, you might have picked up some weed seed there.

Like I said, they're on the same stems as the small leaves (except a few that aren't). Yep, I've confirmed that. I'd show you a picture showing that, except the plants are all tangled up. The big ones taste like marjoram too. The large leaves are opposite, as are the small leaves. They are, however, somewhat pointed, which the small leaves are not. Now, I believe that wild marjoram (volgare) has larger leaves than sweet marjoram (majorana). Don't suppose that, like parsley, which I posted about a few days ago, we're seeing some sort of reversion? These aren't anonymous transplants. They're from Territorial seeds.

Sure, maybe cross-pollenation. Or perhaps some reversions happening. Or maybe you just have herbs that seem to grow different leaves from the same plant. You have parsley that does it, why not the marjoram as well? Perhaps it's a growth cycle thing, or something with the nutes or environmental that's causing your leaves to change on the same plant.

I can see several different seedlings there including a tomato and what might be a birch. I’m very sceptical, in fact I’m certain, that this is not any kind of marjoram and it is definitely nothing like wild marjoram. I think the mix is contaminated. Pull that big one out. I‘ll bet it is not connected to the smaller leaved plants.

Gee, y'all are hard to please. The big leaves ARE connected to the smaller leaves.

And no, there are no tomatoes in there. I should add that I planted a slew of seeds from that packet, and they all came up looking like this. The stuff sure tastes like marjoram.

Well, if it’s not a tomato, it’s a pepper. At 10:00. unknown serrate seedling at midnight.

As for the abberrant seedling, I’d contact the seed company. That is a truly weird phenomenon.

I did contact the seed company. I was mistaken. It was Botanical Interests. I sent them the picture I posted here. April Shelhon, their experienced horticulturalist, answered promptly and says, quite simply, that both leaf sizes are not unusual for marjoram. So let's just call it truly weird and be done with it. Nothing aberrant. Besides, if it tastes like marjoram, that's good enough for me.

Well, its a new one on me. Never seen the large leaves on Marjoram. I’ve learned something today.

It has been more than two years of Covid. Anything is possible with our human lack of meddling. 😜 I’d still like a plant with your two versions of parsely.

Might it be etoliated from getting less direct sun?

And in the 1st photo, I do see what looks like a pepper seedling front and center. Its stem is emerging from the soil...

Etiolation wouldn't make the leaves so much bigger and a different shape.

In fact, etiolation makes smaller leaves (though perhaps more elongated). Besides, everyone there gets the same amount of light.

I thought I'd give an update on this. VERY WEIRD. The oddness continues. What was happening two months ago was that my marjoram was indoors in a pot in the winter. Temps in the high 60sF. Minimal sunlight. Almost all leaves were very small (a quarter inch across), and I was occasionally seeing a larger leaf. See picture above. The seed providers said that this was normal. Now, the pot is outside, where the temps are near 100F, and the plant is getting lots of sunlight. Kaboom! Now ALL the leaves are large (more than an inch across.) Same leaf shape, but wildly different sizes. This does sound somewhat like etiolation, but I've never seen such a profound effect.

I’d be interested in seeing a picture. Any chance?

Is the flavour/scent any different between the two leaf types?

See below.

The regrowth leaves are the big ones. The small ones at the center are fill-in that I just transplanted into the pot. These big leaves are actually a couple of inches across! They are a little more pointed than I would have expected. I can't believe that these are weeds because the soil was sterilized before planting, and I'm pretty sure that they are the original plants. I don't notice anything unusual about the taste.

They really don’t look like anything Marjoram at all. Even the texture is wrong. More like peppers or something. If they are Marjoram they would have a strong herbal smell and taste. But I find it really hard to believe.

They strongly resemble pepper plants to my eye as well.

The tiny plant in between them looks like marjoram, tho...

Here's what marjoram looks like - leaves are fuzzy and no more than 1/2" - usually smaller:

I have a plant in a pot that's many years old now, it has a woody 'trunk' like a miniature tree.