Many commercial sellers seem to list
T. tarda as "
T. tarda (syn.
dasystemon)" for some reason. They have been doing this for as long as I can remember looking at bulb catalogues (about 40 years). I can only assume that a long time ago
T. tarda was circulating in cultivation but wrongly named / misidentified as
T. dasystemon. Given that
T. tarda is not a synonym for
dasystemon I can't understand why they are still doing this.
Misidentifications happen, correct the mistake, move on.
And while we're at it, "Fritillaria uva-vulpis (syn. assyriaca)" is another common one of these.... there is really no excuse for it, they are different species.
Anyway, rant over!
Tristan