[contingo]

From the introduction, which starts by trying to give some wider taxonomic context:

>The genus Ilex comprises about 450 species growing in the tropical regions of South America and Asia. Ilex trees are located exclusively in South America...

The roughly 500-600 species in the genus Ilex are commonly called hollies and include the European Christmas holly, I. aquafolium. The genus overall has a worldwide distribution over both tropical and temperate regions, there is no particular concentration of diversity in the South American tropics. Strange to get basic facts so wrong in the opening sentences.

[DonaldFisk]

"Ilex trees are located exclusively in South America: in northern Argentina, southern Brazil, Uruguay, and Paraguay, where they cover an area of approximately 540,000 km2." That's the range of Ilex paraguariensis, the species from whose leaves yerba mate is made, not Ilex trees in general.

[doodlebugging]

A related species is Yaupon Holly that grows all over the Gulf Coast region from Texas to Florida.

That one is Ilex vomitoria and is the only native caffeine producing plant that grows in north America. I make tea from the leaves after roasting them for a few minutes on low heat. You can find Yaupon Tea for sale in quite a few places now after articles about it appeared a few years back.

It is a hardy bush that can form thickets that are nearly impenetrable. It is used as a landscape plant here in Texas and most nurseries carry dwarf varieties that form hedges. I prefer the trees. They can reach 20' tall and are covered in berries during winter. On the coldest days here in N Texas the birds descend on my trees and feast until everything is gone.

I agree that it seems like they ignored a lot of related plants in their description.

[gen220]

Do you have a Yaupon brand you can recommend? I tried some in college and found the taste too bitter (like the leaves had been improperly-stored for way too long, kind of like how basil tastes when poorly-dried).

But I'm very into the idea of finding a good Yaupon, insofar as it reduces the carbon footprint of shipping things around the world & such.

[Kaibeezy]

You’re right, it’s wrong, but not that wrong. Several sources indicate the majority of Ilex species occur in South America and Asia, so that was probably what they meant to say. Ilex paraguariensis is limited to Brazil, Paraguay, Uruguay and Argentina, and are clearly the “Ilex trees” referred to in the second sentence quoted. So, yeah, it’s imprecise and syntactically sloppy but not that far out, and not the main point of the paper, but as Jack Reacher says, “details matter”.

[contingo]

It's woefully wrong for something in the primary literature. Yes, I understood what information they were sloppily failing to be precise about. If I were refereeing this paper I'd insist on a correction.