Peddocks Island Plants

In a two-year project funded by the Island Alliance to study the vegetation of the Boston Harbor Islands National Park Area, 32 islands were surveyed and inventoried for vascular plant species. Field surveys began on 9 June 2001 and ended on 30 September 2002.

Below is the data collected for Peddocks Island.

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Island Acreage: 210.4
Owner: MDC
Rare Plants: Rumex pallidus (T)
Quadrangle: Hull, MA
Survey Dates: 15 June, 2001; 10 July, 2001; 2 August, 2001; 7 September, 2001; 21 June, 2002, 12 August, 2002; 30 September, 2002.

Data Notes:
* = introduced species
(v) = voucher specimen
(p) = photograph

Due to formatting restrictions, species scientific names are not italicized in the data table.

Plant information on Peddocks Island

Species Scientific Name	Species Common Name	Family	Date Observed	Habitat

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Notes on Habitats and Flora

With a variety of old fields, thickets, and woodlands, Peddocks Island has one of the most varied assortment of upland habitats on the Harbor Islands. The East Head drumlin has the finest stand of large trees anywhere on the Islands outside of World’s End: an extensive woodland with a canopy of large Norway maples (Acer platanoides). Other trees in this Norway maple-dominated community include white ash (Fraxinus americana), hackberry (Celtis occidentalis), and black pine (Pinus nigra). As in other Island woodlands, shrub and herbaceous species are to a large extent comprised of non-native plants.

Thickets occur throughout Peddocks Island. A good example is a mature thicket on the highest part of the central drumlin, which includes species unusual for the Islands such as smooth shadbush (Amelanchier arborea) and red chokeberry (Aronia arbutifolia). Dense, forbidding thickets on Prince Head have the mix of species more typical of Harbor Island shrub communities: oriental bittersweet (Celastrus orbiculatus), bayberry (Myrica pensylvanica), staghorn sumac (Rhus typhina), and saltspray rose (Rosa rugosa).

Field habitats range from weedy sites adjacent to roads, trails, and buildings to dry, open habitats in the narrow, sandy necks between drumlins. Plants found in these dry habitats include four-o-clocks (Mirabilis nyctaginea), bracted plantain (Plantago aristida), and sleepy catchfly (Silene antirrhina).

Beach strand habitat occurs around most of the island’s perimeter. Prince Head has long stretches of sandy beach, and its northeastern side has the only large population of seabeach dock (Rumex pallidus) in the Harbor Islands. In 2001, this population, which is scattered along the beach for a distance of about 800 feet, consisted of 160 fruiting stems and 50 vegetative stems. Most of the mature, fruiting seabeach dock plants were found right at the base of the drumlin’s eroding cliffs, where the soils have some moisture and organic matter. Rumex pallidus plants that occured in drier, sandier soil below the uppermost edge of the high tide line were more anemic, usually consisting only of basal leaves.

There are no immediate threats to these seabeach dock plants, but the progressive erosion of Prince Head could diminish the population by burying plants and creating drier and more nutrient-starved conditions than the species can tolerate. That said, this population has increased since MNHESP started tracking it in 1981, the year the plants were discovered by Dale Levering.

Wetland habitats include a salt marsh between the central drumlin and Prince Head, and a disturbed, brackish pond on the island’s southeast corner. The salt marsh is one of the largest on the Islands (though far smaller than the one at Thompson Island). One of the only Island occurrences of saltmarsh arrowgrass (Triglochin maritimum) was found in this marsh.

Previous florisitc surveys on Peddocks include inventories by Dale Levering (1978) and Bill Perkins (unpublished, 1980’s?—need to locate paper). Perkins found a population of the infamous kudzu vine (Pueraria lobata) around the old military buildings on East Head, one of only two known locations in Massachusetts for this more southerly invasive plant (Sorrie and Perkins 1988). Kudzu was not observed in this survey (found 6/21/02).