I consider that there is but one species of this genus: two of the <lb xmlns="http://www.tei-c.org/ns/1.0" />varieties occur in <placeName xmlns="http://www.tei-c.org/ns/1.0" ref="https://edition-humboldt.de/H0005696 https://www.geonames.org/6255148">Europe</placeName>, a third in the <placeName xmlns="http://www.tei-c.org/ns/1.0" ref="https://edition-humboldt.de/H0009136 https://www.geonames.org/6252001">united states</placeName>, and the <lb xmlns="http://www.tei-c.org/ns/1.0" />fourth in the island of <placeName xmlns="http://www.tei-c.org/ns/1.0" ref="https://edition-humboldt.de/H0009525 https://www.geonames.org/3370683">Tristan d’Acunha</placeName>, but there are intermediate <lb xmlns="http://www.tei-c.org/ns/1.0" />varieties from the same places. The <placeName xmlns="http://www.tei-c.org/ns/1.0" ref="https://edition-humboldt.de/H0005696 https://www.geonames.org/6255148">European</placeName> species occur as far South <lb xmlns="http://www.tei-c.org/ns/1.0" />as the <placeName xmlns="http://www.tei-c.org/ns/1.0" ref="https://edition-humboldt.de/H0009617">Tyrolese Alps</placeName>, & extend to <placeName xmlns="http://www.tei-c.org/ns/1.0" ref="https://edition-humboldt.de/H0010187 https://www.geonames.org/2744011">Seeland</placeName>.