Hard to say without a flower if this is collina.  In any case, it’s gorgeous and one of the slowest growing plants I’ve ever propagated (filmy ferns not far behind this one).  I’ve had it for nearly 4 years and only ever propagated four or five plants. It grows from leaf cutting but in my experience has taken around a year for new growth to emerge.  Being so slow, I’m not sure how large it gets.  It’s covered in small hairs.  The imported plant I received died except for one leaf, which was about 5″ in length.  It’s possible it gets larger, but, it might take a decade. The paper describing Acranthera collina can be found here. It was described in 2019.  

Available plants are 2 years old and well rooted in 2″ pots.  The last photo is representative of the size plants available. Very limited quantity available.