There are many different coastal grassland and heathland assemblages found among the sandplains of Cape Cod. Heathlands are areas where low growing shrub species dominate the vegetation cover. They generally occur on well drained, acidic soils. The coastal heathlands of Cape Cod National Seashore are home to a number of globally rare species. Heathland assemblages on Cape Cod are characterized by the presence of broom crowberry as well as other low growing shrubs and often contain a wide variety of forbs, grasses and lichens.
Broom crowberry is a regionally endemic plant that is found in coastal sandplain communities from New Jersey to Newfoundland. It is listed as a Species of Special Concern by the state of Massachusetts. Cape Cod has long harbored some of the largest and best known populations of broom crowberry, with descriptions by early settlers depicting carpets of the plant and healthy seedling recruitment. Unfortunately many of the populations on Cape Cod and the surrounding islands are aging and it is unknown if recruitment is sufficient to maintain these populations. Current broom crowberry research efforts are focused on seed dispersal and fire management and hope to shed more light on the subtle ways in which the plant species interacts with and persists in its environment.