Let's rather discuss the desirability of including Celtis in the
Cannabinaceae

You piqued my curiosity. This is what I found:
Family Latin Name:Celtidaceae + Cannabinaceae
Family Common Name:Hackberry Family
Order:Rosales
Order Type:Eudicots-rosids I
Defining Features:Wind pollinated. Fruits are adapted for dispersal by birds.
Defining Morphology:Floral Features: Flowers are usually unisexual (Plants are
monoecious). Flowers are very small and borne in an inflorescence of
determinate, axillary clusters, raceme-like or reduced to a solitary flower.
Ovaries are superior with apical placentation. Fruit and Seed Features:
Dicotyledon. Fruits are often drupe and have sweet flesh. Vegetative Features:
Habit as trees or shrubs or as a vigorous herb, either twining or erect, with
strong stem fibers. Leaves are alternate, simple, deciduous with oblique bases
or compound or palmately lobed and either alternate or opposite. Leaves margin
is serrate. Stipules are present.
Distribution:Temperate regions of N. Hemisphere and few species in the tropics.
Economic Use:As a source of timber, as cultivated garden ornamental, as the
source of hops used in brewing beer and as the source of marijuana, hashish and
hemp fiber. The family has a long history of association with humans, which has
resulted in many various cultiva
Number of Genera Globally:11
Genera Planted in Garden:Celtis, Humulus.
Number of Species Globally:180

The older authorities, including IPNI (IK) include Celtis in the Ulmaceae,
which belongs to the order Urticales. When did the above happen, & what is the
rationale?
Iris,
Central NY, Zone 5a, Sunset Zone 40
"If we see light at the end of the tunnel, It's the light of the oncoming
train."
Robert Lowell (1917-1977)