Hornworts of Berrien County, Michigan, and Vicinity

The hornworts (Class Anthocerotopsida) are believed to be the most ancient of the non-vascular plants. Lacking roots, stems, and typical leaves, the hornworts are easily overlooked by the casual observer.

The hornworts constitute a relatively small group of primitive plants: 180 species are recognized worldwide, 17 are known from the U.S. and Canada, and 4 have been verified from Michigan.

The two species known from southwestern Michigan (i.e., an area within 70 miles of Berrien Springs, Michigan, encompassing the counties of Allegan, Barry, Berrien, Branch, Calhoun, Cass, Kalamazoo, and Van Buren) represent 1 order, 2 families, and 2 genera.

The following list is based on Howard Crum’s (1991) Liverworts and hornworts of southern Michigan. Michigan counties within a 100-mile radius of Berrien County with confirmed records are listed in brackets. Habitat descriptions in quotations are from Crum.

ORDER ANTHOCEROTALES

Family Anthocerotaceae:

Anthoceros laevis – “on wet soil in harvested corn and soy bean fields and also in fields of winter wheat” [Kalamazoo]

Family Notothylaceae:

Notothylas orbicularis – “on heavy, wet soil in old fields, often at the corners of corn, soybean, and wheat fields, in ruts and tractor tracks, in pastures trodden by cattle, and on muddy footpaths” [Kalamazoo]

Acknowledgment: I thank the librarians and staff of the Buchanan District Library for their help in securing a copy of Crum (1991) from the Michigan e-Library.