Isoetes engelmannii A. Braun
Common Name: ENGELMANN'S QUILLWORT
Coefficient of Conservatism: 10
Coefficient of Wetness: -5
Wetness Index: OBL
Physiognomy: Nt Fern Al
Status: E
Isoetes engelmannii plant D. F. Brunton plant

Disjunct from farther east and known only from one site in Allegan Co., in the wettest areas of a sandy swale between fossil dunes ridges, with typical Coastal Plain disjuncts. During dry years, this species is terrestrial, but in wet years it is aquatic or emergent.

This is the largest quillwort in Michigan, its broad, pale green leaves extending to 48 cm (in Michigan collections). The megaspores of this diploid species are tiny (comparable in size to those of I. echinospora) and exhibit a distinctive ornamentation pattern of tall, evenly reticulate ridges completely anastomosing into a network. A number of distinct polyploid (2n = 44, 2n = 66), species have been recognized in recent years elsewhere in the eastern United States from what were formerly considered larger-spored populations of this species.

Locations

Allegan County

Citation:

MICHIGAN FLORA ONLINE. A. A. Reznicek, E. G. Voss, & B. S. Walters. February 2011. University of Michigan. Web. December 15, 2017. http://www.michiganflora.net/species.aspx?id=1489.