"Dutch elm" is a (natural) hybrid between Ulmus glabra (Wych elm) and Ulmus minor (field elm), with the botanical name Ulmus x hollandica. In Europe, the first two species readily hybridize, creating fertile offspring. That means that locally U. glabra is very common...while somewhere else U. minor might be very common...or in a third area where both species exist, Ulmus x hollandica is the most prevalent. Confusing!
All three species have excellent wood with similar properties. All great bowwood. I prefer to split and de-bark elm as soon as possible. Insects really like the sapwood, and it dries easily with little drying checks. Seals the ends of course, but it's not necessary to seal the back as well, IMO.
The two words "Dutch elm" are more often used in the context of "Dutch elm disease". A devastating fungal disease affecting basically any species of Ulmus, named after the country where if was first discovered and described - not the country where the disease originates from.