Hi Gillspec

Personaly i don't know the answer but i always google everything.

This link was the result ... hope it helps

http://www.crocus.co.uk/plants/_/perennials/classid.2917/

Hellebores are confusing, like many other plants, because they interbreed easily - producing hybrids, which are just the offspring from plants of different strains.
Hybridus is the latin word for hybrid - so the plant so described is not being given a specific name, it's being called a Hellebore, but you knew that anyway.

And "hybridus" can be applied to all sorts of things - unless you're breeding true strains of, say, bull dogs or Charolais cattle or fruit flies, everything is a hybrid!

"Orientalis" should mean "from the orient".

Hellebores come in lots of different species - for example, Hellebore niger (Christmas rose), H. foetidus (Stinking Hellebore), H. argutifolius (Corsican hellebore).
Hellebore orientalis is one of these species - it comes from an area in the Ukraine and the Caucasus and is one of the "parents" or great ...great... great grandparents of lots of hybrids available in garden centres etc.

Don't stress about all the confusing names, if you like it, buy it

have a look at - http://www.hellebores.org/helleborushybridus.html

Gill - just to add to Beatties answer...the Hellebores that you will most frequently see offered for sale are all forms of H. x hybridus.

BUT, unfortunately, many (possibly most) sellers persist in calling these plants H. orientalis. The true species of H. orientalis is very rarely seen in cultivation in the UK, is not particularly ornamental in flower, and is very much the preserve of collectors rather than general gardeners.

Some sellers refer to the hybrids as "H. orientalis hybrids", but that's incorrect too, since such plants are actually inter-crosses of different forms of H. x hybridus and have no direct relationship with H. orientalis.

Also the name Helleborus x hybridus is the true, valid published botanical name for these complex inter-species Hellebores, it's not just a short-hand way of saying that the plants are hybrids...if you see what I mean!

The only reason that non-specialist sellers persist in using the invalid name is that it is more familiar to some gardeners, and so the assumption is that the plants will sell better when labelled H. orientalis. Having said that the name H. x hybridus was first published/used for these plants in 1894, so it's not exactly new!

Thanks for the clarification Ilex.

Thanks from me too. I think this may be one of those questions that some people will never understand fully. Not helped if the sellers aren't labelling their plants correctly.