Plummers Island

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Studies of lichen floristics

Past and present flora:

· Floristic studies of lichen communities have been done at Plummers Island since the turn of the century.

· Early collections by Bruce Fink and members of the Washington Biologists Field Club are deposited in the United States National Herbarium, Smithsonian Institution.

· The Island is located just below the American Legion Bridge, built in 1965,  that carries the Capital Beltway (Interstate 495) across the Potomac River.

· Studies of lead accumulation by the rock-inhabiting lichen Flavoparmelia baltimorensis indicate that fallout patterns have changed significantly in the past 100 years.

· Significant floristic changes have also taken place during the past century, including a general reduction in species number and an absence of species known to be pollution-sensitive.

· Continued biotic surveys of the Island may help to document recovery of lichen and other communities as air quality in the region improves.

· Present-day macrolichen diversity is relatively accurate, but the diversity of crustose species has not been studied since the 1930's. The pollution-sensitivity of crustose species is also not well known at present.

· All nomenclature follows the North American Lichen Checklist maintained by T.L. Esslinger at North Dakota State University.

Bark-inhabiting macrolichens collected at Plummers Island (sensitive species in red):

1917-1935: Anaptychia palmulata Coccocarpia palmicola Collema leptaleum Collema subflaccidum Dirinaria picta Flavoparmelia caperata Fuscopannaria leucosticta Leptogium azureum Leptogium corticola Leptogium cyanescens Myelochroa aurulenta Parmelia squarrosa Parmotrema cetratum Parmotrema reticulatum Phaeophyscia erythrocardia Phaeophyscia adiastola Phaeophyscia rubropulchra Physcia americana Physcia millegrana Punctelia rudecta Pyxine sorediata Usnea sp.

1982-2004: Candelaria concolor Dirinaria aegialita Flavoparmelia caperata Flavopunctelia flaventior Parmotrema dilatatum Parmotrema hypotropum Phaeophyscia adiastola Phaeophyscia rubropulchra Physcia millegrana Punctelia rudecta Pyxine caesiopruinosa Pyxine sorediata

Crustose lichens collected at Plummers Island (all habitats):

1917-1935:

Acarospora fuscata (rock)

Anisomeridium biforme (bark)

Amandinea punctata (bark)

Arthonia sp.

Arthonia caesia (bark)

Arthonia dispersa (bark)

Arthonia punctiformis (bark)

Arthothelium spectabile (bark)

Bacidia polychroa (trees)

Bacidia rubella (bark)

Bacidia schweinitzii (bark)

Buellia spuria (rock)

Caloplaca aurantiaca (bark and rocks)

Caloplaca feracissima (rock)

Caloplaca flavovirescens (rock)

Chrysothrix candelaris (rock)

Dimelaena oreina (rock)

Graphis scripta (bark)

Lecanora campestris (bark)

Lecanora muralis (rock)

Lecanora varia (bark and rocks)

Lepraria incana (rock)

Lepraria lobificans (tree bases, rocks)

Lepraria neglecta (rock)

Micarea erratica (rock)

Ochrolechia trochophora (bark)

Opegrapha varia (bark)

Opegrapha vulgata (bark)

Pertusaria sp. (bark)

Polysporina sp. (rock)

Porpidia albocaerulescens (rock)

Pyrenula pseudobufonia (bark)

Rhizocarpon petraeum (rocks)

Rinodina sp.

Rinodina ochrocea (rock)

Strigula stigmatella (bark)

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Soil/rock inhabiting macrolichens collected at Plummers Island (sensitive species in red):

1917-1935: Cladonia apodocarpa C. caespiticia C. cervicornis subsp. verticillata C. chlorophaea C. coniocraea C. cristatella C. cryptochlorophaea C. furcata C. grayi C. macilenta C. peziziformis C. piedmontensis C. pleurota C. polycarpoides C. subcariosa C. subtenuis Collema flaccidum Dermatocarpon miniatum Flavoparmelia baltimorensis Peltigera canina Physcia subtilis Xanthoparmelia conspersa Xanthoparmelia plittii Xanthoparmelia subramigera Xanthoparmelia viriduloumbrina

1982-2004: Cladonia apodocarpa C. subtenuis C. caespiticia C. pyxidata Dermatocarpon miniatum Flavoparmelia baltimorensis Physcia subtilis Xanthoparmelia conspersa Xanthoparmelia plittii

Some of the collectors of lichen specimens at Plummers Island.

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Early literature on lichen flora of Plummers Island:

Fink, B. 1935. The Lichen Flora of the United States. Univ. Michigan Press, Ann Arbor.

Leonard, E.C. and E. P. Killip. 1939. Natural history of Plummers Island, Maryland. VIII. Lichens. Proc. Biol. Soc. Wash. 52: 23-26.

Robbins, C. A. and S. F. Blake. 1931. Cladonia in the District of Columbia and vicinity. Rhodora 33: 145-159.