Beach pinweed (Lechea maritima) COSEWIC assessment and status report: chapter 11

Special Significance of the Species

Canadian populations of beach pinweedare of a variety endemic to the southern Gulf of St. Lawrence and have a very limited geographic range. Only 15 populations in five regions of occurrence are known to exist on New Brunswick’s eastern coast and Prince Edward Island’s north coast. These populations are unique in representing the northern and eastern limit of Lechea maritima range and are approximately 370 km disjunct from the closest occurrence in Maine’s Hancock County. Having presumably become disjunct from the species’ main range following glacial retreat, Gulf of St. Lawrence populations have differentiated to the point of taxonomic recognition. The genetic distinctness of this variety is undocumented and should be further investigated. The effects of isolation, genetic drift and natural selection can produce genetic, ecological, and morphological divergence in peripheral populations, giving those populations a disproportionate significance to the species as a whole (Lesica and Allendorf 1995, Garcia-Ramos and Kirkpatrick 1997).

Lechea maritima is one of a distinct suite of southern coastal species, mostly of estuaries, having disjunct populations along the relatively warm Gulf of St. Lawrence coast, including the COSEWIC species eastern lilaeopsis (Lilaeopsis chinensis, discovered during 2006 AC CDC fieldwork) and “Bathurst” aster (Symphyotrichum subulatum). In a broad sense, the species shares its dune habitat with two species designated as endangered by COSEWIC; the Piping Plover (Charadrius melodus) and the Gulf of St. Lawrence aster (Symphyotrichum laurentianum), as well as a substantial number of provincially rare species of dunes.

No evidence of aboriginal traditional knowledge or use of this or other pinweed species was found (Lennox Island, PE and Elsipogtog and Burnt Church, NB bands contacted), or of any other human use of any pinweed. The only on-line reference to the genus Lechea in medicine refers to frostweed (Helianthemum canadense), a member of the Cistaceae formerly called Lechea major (Grieve 1931).

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