Very common species like Achillea millefolium, Filago pyramidata or the genus Senecio lack even the plant kingdom:
New backbone building algorithm
Strange enough the genus Achillea is properly included in the classification: http://www.gbif.org/species/3119995
I suppose you already realized, but all the species mentioned belong to different genus in the same family.
These all have proper classifications now in the new backbone: