Honey locust, Gleditsia tricanthos, has both pinately
and bi-pinately compound leaves, while the related water locust, G. aquatica, only has the former like
black locust, Robina psudoacacia. The legumes
of honey locust have a sweet interior, which resulted in the vernacular name,
and they are much longer than those of water locust. Another difference is wetland indicator
status where it is obvious from both the specific epithet and the common name
that water locust is an obligate wetland species while honey locust is more
likely to be found in uplands although I often see it on sandbars and in an
early successional stage of fields that are in flood plains. The most notable feature of honey locust is
the thorns that can be over a foot long and branch three times as the specific
epithet indicates. The number of thorns varies
widely from nearly obscured trunks to those with no thorns all that are considered to be a form known as thornless
honey locust, G. triancanthos form inermis.
This has made a thornless male cultivar very popular as a street tree because there are no legumes besides having leaves that disintegrating thus leaving virtually no mess with a need to rake in the fall. As
a result of this there is the risk from overplanting such as occurred with the American
elm, Ulmus americana