[antoncohen]

> Eusociality typically requires two other conditions. ... And since the ferns spread asexually on shared roots, they don’t actually exhibit an active system of resource acquisition typical of brood care.

> One key question is what defines an individual fern. If a colony can begin with a small plume of strap fronds sticking up from a few nest fronds and then spread asexually on the same roots, perhaps it is a single plant

There is a lot of talk about the amazing cooperation of these plants. And then they say it is actually one plant. Is it interesting if one plant grows different leaves at different heights?

[rackjack]

"But Uli Ernst, a behavioral ecologist at the the Apicultural State Institute at the University of Hohenheim, Germany, adds that since older and younger ferns (their clones) live together sharing water and nutrients, one could technically call these overlapping generations and brood care." (emphasis mine)

In the same paragraph, clones, not the same plant. Strawberries clone themselves. They aren't the same plant.

"The difference, Burns says, is that the whole strawberry patch looks the same. The ferns, by contrast, differ markedly in morphology and reproduction depending on their role in the colony." (emphasis mine)

Right underneath the paragraph you were quoting, they have different roles, not just different heights.

Also,

"Drawing conclusions about staghorn social organization may ultimately hinge on the nuances of eusociality—some definitions frame the concept as more of a spectrum, notes evolutionary biologist Guy Cooper, at the University of Oxford in the UK, who was not involved in the fern study." (emphasis mine)

So I guess its significance depends on how you define "eusocial".

[pvaldes]

> The difference is that the whole strawberry patch looks the same.

In fact this depends a lot on the location, soil and age of the clones.

> The ferns, by contrast, differ markedly in morphology and reproduction depending on their role in the colony."

First of all, population is not the same as colony.

Second, many plants have auxiliary structures (temporary, marcescent or permanent). The concept of bract, thorn, nectarium or stipula is not a strange one for botanists but those are parts of one individual, not individuals in a colony.

Is well known that gametophytes and sporophytes are different individuals. Many algae and ferns have it. If we want to bend the concepts for non useful reasons, then any pregnant woman should be called an "eusocial colony" with three individuals.

[marcosdumay]

What is the difference between a very cooperative colony of independent single cell organisms and a multi-cellular organism?

On practice the only difference is on the level of collaboration. You get a similar phenomenon here, it's different because those plants collaborate less than the leaves of a single plant, so we give them a different name. From that point of view, this finding is quite boring. What makes it interesting is that it's an independent evolution of collaborative behavior.