When I tried to add this plant I was directed to A. millefolium. The A. millefolium is certainly completely different from the A. tomentosum in height and in color.
Catalogue of Life provisionally accepted the name.

It's tomentosa, not "tomentosum." In this case, the Catalogue of Life shows it as a provisionally accepted name, a synonym of A. leptophylla, and a synonym of A. millefolium. It's clearly unresolved here, but the ITIS search page says it's not accepted and is a synonym of A. millefolium.

http://www.catalogueoflife.org...

http://www.itis.gov/servlet/Si...

Well, have a look at the pictures and see how different it is from A. millefolium. The maximum height is about 4 inch.

I can see Jonna's confusion. I looked both plants up on the internet and they look completely different from one another?

Achillea tomentosa (Wooly Yarrow) http://www.ces.ncsu.edu/depts/...

Achillea millefolium (Western Yarrow, Common Yarrow) Taller than A. tomentosa https://www.missouribotanicalg...

We cross posted Jonna. Nice photos.

Achillea millefolium is a highly variable species. Plants can be anywhere from 3 inches to 3 feet tall and, although its flowers are usually white, they can also be pink, red, yellow, orange, lavender, among others. Achillea tomentosa is well within that range.

Sorry, but I do not agree. I grew the A, tomentosa twice from (different sources) seeds and it's really different from A. millefolium. A. millefolium grows wild in my region, but it never crossed with the A. tomentosa. I also had some A. millefolium ' paprika' and ' pink' and they cross easily with the A. millefolium.

I am an amateur, but I won't upload the pictures of 'my' A. tomentosa as A. millefolium. Sorry, but it doesn't feel good for me to do that.

I think if Kent says it's right, then it's right. He's not an amateur and we would do well to learn from his knowledge and wisdom.

Dave, did you see the pictures? And did you see the difference in height and leaves?
I don't want to disagree with Kent, he's an expert, and I'm not, but still it doesn't feel good to me to publish my pictures of the A. tomentosa as A. millefolium. Sorry, but I do not want to do that.

Well, I'm certainly no expert on the genus Achillea. However, the opinion of the people who are experts is that A. tomentosa is not distinct enough from A. millefolium to be considered a separate species. As I said before, A. millefolium is an extremely variable species. It has been vexing plant taxonomists for years and no doubt will continue to do so for years to come. :smily:

But, as of this moment, quite a few formerly recognized species of Achillea are lumped into A. millefolium, including A. tomentosa.

Jonna, the appearance of things isn't a good argument. Broccoli rapa, for instance, includes Chinese Cabbage, Broccoli, and Turnips, and I'm sure you'll agree that they look quite different.

zuzu said:Jonna, the appearance of things isn't a good argument. Broccoli rapa, for instance, includes Chinese Cabbage, Broccoli, and Turnips, and I'm sure you'll agree that they look quite different.

I know Zuzu, but Broccoli rapa is mostly named with a 3rd name, so we can see what variety is offered.

KentPfeiffer said:Well, I'm certainly no expert on the genus Achillea. However, the opinion of the people who are experts is that A. tomentosa is not distinct enough from A. millefolium to be considered a separate species. As I said before, A. millefolium is an extremely variable species. It has been vexing plant taxonomists for years and no doubt will continue to do so for years to come. :smily:

But, as of this moment, quite a few formerly recognized species of Achillea are lumped into A. millefolium, including A. tomentosa.

Just don't want to confuse people with posting the pictures of ' my' A. tomentosa as A. millefolium. Catalogue of Life (that was advised to me to look if a plant name was correct) provisionally accepted the name

Will keep posting pictures of other plants, but will wait to add the pictures of the A. tomentosum.

You're missing my point. I'm saying that plants with vastly differing characteristics can be classified as the same species, so the fact that one Achillea has different leaves and a different height does not necessarily put it in a different category than others. It's true that Brussels Sprouts and Turnips have different common names, which I assume is the "third name" you mention, but they are not differentiated by their species name. You can always include your preferred name (the synonym) in your photo caption if you wish.