About Alnus maritima (Marshall) Muhl. ex Nutt.
Alnus maritima (Marshall) Muhl. ex Nutt., commonly called seaside alder, delmarva alder, or brook alder, is a species of shrub or small tree belonging to the family Betulaceae. This species is endemic to the United States, where it occurs naturally in three separate disjunct populations: one in Oklahoma, one in Georgia, and one spanning Maryland and Delaware on the Delmarva Peninsula. Alnus maritima is the only Alnus species native to North America that blooms in autumn; all other native North American alders flower in the spring. This autumn-blooming phenology is shared with two old-world Alnus species that are endemic to southeast Asia: Alnus nitida and Alnus nepalensis. The strong similarity in their timing of anthesis has led to these three species being classified as the only members of the subgenus Clethropsis.
