When it comes to thorny trees in southeast Michigan floodplain forests, the most impressively thorny is easily the honey locust (Gleditsia triacanthos, Fabaceae). It’s not the only thorny tree I find, however. Just as common are hawthorns (Crataegus sp., Rosaceae).
While not nearly as thorny as honey locusts, hawthorns make up for it by producing large numbers of showy white or pink flowers in April and May:
The flowers are very similar to those of other members of the rose family, including apples, cherries, pears, and plums. Among these some wild plums (Prunus sp.) also have thorns, but the lobed leaves shown here are distinctively those of hawthorns.
Also like many other members of the rose family, hawthorns produce fruit that are pomes, much like small apples. After the flowers are pollinated in the spring, the fruit grow through the summer and drop from the trees in the fall.