Dracaena draco

[Kenneth Skiles]

I went to a local greenhouse to buy some assorted dracaena.  I found the
deremensis, fragrans, marginata, sanderiana and godseffiana.  But when I
asked about the draco that I didn't see, the guy told me that they don't
sell those.  He said they get way too large for indoor plants, sort of 
like a large tree.  The book I'm using says these draco only get about
4 ft tall.  Who is wrong, the book or the greenhouse guy?
The book is 'The Photographic Encyclopedia of Indoor Plants' by 
David Squire.