''Alnus maritima'', the seaside alder or brook alder, is a species of shrub or small tree in the family

Betulaceae Betulaceae, the birch family, includes six genera of deciduous nut-bearing trees and shrubs, including the birches, alders, hazels, hornbeams, hazel-hornbeam, and hop-hornbeams, numbering a total of 167 species. They are mostly natives of ...

. ''Alnus maritima'' is

endemic Endemism is the state of a species being found only in a single defined geographic location, such as an island, state, nation, country or other defined zone; organisms that are indigenous to a place are not endemic to it if they are also foun ...

to the United States, and is found naturally in three disjunct populations in

Oklahoma Oklahoma ( ; Choctaw language, Choctaw: , ) is a landlocked U.S. state, state in the South Central United States, South Central region of the United States. It borders Texas to the south and west, Kansas to the north, Missouri to the northea ...

Georgia Georgia most commonly refers to: * Georgia (country), a country in the South Caucasus * Georgia (U.S. state), a state in the southeastern United States Georgia may also refer to: People and fictional characters * Georgia (name), a list of pe ...

, and in

Maryland Maryland ( ) is a U.S. state, state in the Mid-Atlantic (United States), Mid-Atlantic region of the United States. It borders the states of Virginia to its south, West Virginia to its west, Pennsylvania to its north, and Delaware to its east ...

and

Delaware Delaware ( ) is a U.S. state, state in the Mid-Atlantic (United States), Mid-Atlantic and South Atlantic states, South Atlantic regions of the United States. It borders Maryland to its south and west, Pennsylvania to its north, New Jersey ...

on the

Delmarva Peninsula The Delmarva Peninsula, or simply Delmarva, is a peninsula on the East Coast of the United States, occupied by the majority of the state of Delaware and parts of the Eastern Shore of Maryland and Eastern Shore of Virginia. The peninsula is l ...

. ''Alnus maritima'' is the only autumn-blooming member of the genus ''

Alnus Alders are trees of the genus ''Alnus'' in the birch family Betulaceae. The genus includes about 35 species of monoecious trees and shrubs, a few reaching a large size, distributed throughout the north temperate zone with a few species ext ...

'' native to North America. All other North American alders bloom in the spring. The autumn-blooming

phenology Phenology is the study of periodic events in biological life cycles and how these are influenced by seasonal and interannual variations in climate, as well as habitat factors (such as elevation). Examples include the date of emergence of leav ...

is a characteristic that ''Alnus maritima'' shares with two old-world ''Alnus'' species, ''

Alnus nitida ''Alnus nitida'', the west Himalayan alder, is a species in the genus ''Alnus'', native to Pakistan, the western Himalayas, and Nepal. It is a tree reaching 20 to 25m, preferring to live along the banks of rivers. It is used locally for timber an ...

'' and '' Alnus nepalensis'', which are endemic to

southeast Asia Southeast Asia is the geographical United Nations geoscheme for Asia#South-eastern Asia, southeastern region of Asia, consisting of the regions that are situated south of China, east of the Indian subcontinent, and northwest of the Mainland Au ...

. This profound similarity in their timing of anthesis has led to their classification as the only three members in the subgenus ''Clethropsis''.

Taxonomy

In 2002, the three populations were recognized as

subspecies In Taxonomy (biology), biological classification, subspecies (: subspecies) is a rank below species, used for populations that live in different areas and vary in size, shape, or other physical characteristics (Morphology (biology), morpholog ...

and given the names ''Alnus maritima'' subsp. ''oklahomensis'', ''Alnus maritima'' subsp. ''georgiensis'', and ''Alnus maritima'' subsp. ''maritima'', respectively. While some believe that subspecies ''maritima'' is the oldest of the three subspecies and that the other two disjunct populations resulted from some form of long distance dispersal, evidence from morphometric and

phylogeographic Phylogeography is the study of the historical processes that may be responsible for the past to present geographic distributions of genealogical lineages. This is accomplished by considering the geographic distribution of individuals in light of ge ...

studies indicates that the Oklahoma population (subsp. ''oklahomensis'') is in fact the most ancestral and that the species probably had a wide, continuous distribution across the United States in the past.

References

External links

* * {{Taxonbar, from=Q2589489 maritima Endemic flora of the United States Taxonomy articles created by Polbot