Dockrillia striolata comparison (maybe D. mortii?)

Any Dockrillia experts out there? I have to admit I haven't spent any time researching this yet so just wanted to throw it out there.

I have three plants all labelled as Dockrillia striolata / Dendrobium striolatum. Here are all three. They are from 3 different sources. The one on the left and in the center look similar and also look like on-line photos so I am assuming they are correctly labelled. The one on the right has a completely different form, branching stems and numerous air roots, thinner roots and leaves, more prone to growing pendulous.


Here is the one I am reasonably certain to be D. striolata. There are masses of short roots and the leaves are more robust, relative to the other. This is the only of the 3 that has flowered for me so far. Here is a post of it Dockrillia striolata | OrchidsForum.com


Here is the one in question. The roots are much longer and thinner and there are numerous air roots. The leaves are thinner but of similar length. There is more branching and the plant in general is less robust.


So, I have 2 questions.
Has anyone noticed this much intraspecific variation for this species?
If you think it is not D. striolata do you have any suggestions?

 

Here is a side-by-side comparison

 

Does anyone grow Dockrillia mortii? I'm wondering if the one on the right could be mortii?