Isoetes montezumae A.A.Eaton

  • Authority

    Mickel, John T. & Smith, Alan R. 2004. The pteridophytes of Mexico. Mem. New York Bot. Gard. 88: 1-1054.

  • Family

    Isoetaceae

  • Scientific Name

    Isoetes montezumae A.A.Eaton

  • Description

    Species Description - Rootstock bilobed; leaves ca. 20, ca. 30 cm long, pale toward bases, triangular in mid-length transection; velum covering less than 25% of each sporangium; sporangial walls usually brownspotted; megaspores white, average 400–550 µm in diam., smooth or obscurely to boldly tuberculate-verrucate with girdle smooth; microspores light gray in mass, average 35–45 µm long, echinatetuberculate.

  • Discussion

    Type. Mexico. Me´xico: Plains near Flor de Mari´a, Pringle 3459 (MO!; isotypes BM, E, JE, M, NY!, PH, UC, US, VT).

    Isoe¨tes montezumae and I. mexicana appear to be closely related species that could be treated as a one variable species. Differences in spore size and ornamentation, in addition to what appear to be interspecific hybrids, support recognizing them as genetically divergent species until additional evidence proves otherwise. See discussion under I. mexicana. Most collections of I. montezumae can be identified by their larger spores, tuberculate megaspores, and sporangial walls that are spotted or streaked with patches of brownish cells. In contrast, I. mexicana has smaller spores and more often shiny, smooth, porcelain-like megaspores that are contained within unspotted sporangial walls.

  • Distribution

    Ponds, streams, grassy meadows, roadside ditches in seasonally wet, oak-pine woodlands; 2000–3500 m. August–November. Mexico; Guat.

    Mexico North America| Guatemala Central America|