Himalayan laburnum

I have no objection to taxonomists earning a living, but not if they succeed merely in causing confusion!

I grew this shrub from seed, having previously only known Piptanthus laburnifolius, which was also known as Piptanthus nepalensis, and of which I collected seed in Nepal in 1990. I was therefore pleased some years ago to find in a seed catalogue the plant identified as Piptanthus forrestii, and of which I now have a flourishing shrub of some 5-6ft high and wide.

Having just looked it up to make sure of getting my facts straight, I am now told that the shrub in question is now either known as Piptanthus concolor, or is in fact synonymous with Piptanthus laburnifolius, aka P. nepalensis! Are you confused yet, or is it just me!

Now my experience tells me that the plant known (by me at least!) as Piptanthus laburnifolius isn't hairy and doesn't sucker, and that the plant here illustrated is hairy and does sucker! So how can they be the same? 

If you understand all this and agree with the current nomenclature, then you are either far more intelligent (or disinterested) than I am, or maybe have just woken up from a nap!

Whatever it is, it's a lovely shrub and should be more widely grown. Seed will be available later in the year if you're interested!