Delphinium tatsienense vs. D. grandiflorum

It seems we are naturally ‘inclined’ to want plants that bear names with an exotic resonance.
For example, D. tatsienense may ‘sound’ better than D. grandiflorum; not that the name should be the criterion when choosing what plants to grow.

Few years ago I bought seeds of D. tatsienense, I grew it, boasted about it, collected its seed, until doubts started to creep in about its identity.
I stopped offering seeds but kept some; I grew more seedlings with the precise purpose to have a closer look at it.

The differences between the two species are somewhat minute considering Flora of China (which always gives me the blues when I have to rely on it). Nevertheless, after looking closely and taking meticulous measurements I am pretty sure this is D. grandiflorum; and probably 90% or more, of what goes around in the trades (seeds and plants) as D. tatsienense is actually D. grandiflorum.

The Papilio butterfly, which was busy feeding when I was doing measurements on the cut flowers, gave me the sort of look – “does it really matter?”….Well, it matters for us.

All that’s needed for ID, if you have plants of either of them, are a strong hand lens & small measuring tape. Flora of China see here – link to Delphinium.
Disclaimer: following the link to the Delphinium keys might give you the blues.
Better grow some plants when the seeds are ready, regardless of the name!