Isoetes panamensis, Maxon & C. V. Morton, Ann. Missouri Bot. Gard.

Kessler, Michael & Smith, Alan R., 2018, Prodromus of a fern flora for Bolivia. IV. Isoëtaceae, Phytotaxa 344 (1), pp. 83-86 : 85

Isoëtes panamensis Maxon & C.V.Morton, Ann. Missouri Bot. Gard. 26(4): 272. 1939.

Range:— Western Guatemala to Panama; coastal Ecuador and Peru; interior Brazil, Paraguay, and Bolivia (CO, LP).

Ecology:— Locally common; submerged aquatic and seasonally emergent in fluctuating or ephemeral water bodies such as pools, streams, river banks, and marshes, mostly on muddy ground, sometimes among floating vegetation; to 500 m.

Notes:— Velum rudimentary; megaspores 0.38–0.58 mm in diameter, baculate; microspores 27–40 μm long, smooth, sparsely echinate or papillate; 2 n =44 ( Costa Rica). Throughout its extensive but disjunct range, the megaspores of this species are variable in shape, size, and distribution of the baculi on the megaspores, and microspore ornamentation also varies; more than one taxon may be involved.

A presumably undescribed species of Isoëtes is known from eastern Santa Cruz (Abbott 16383, MO). It has shorter (ca. 15–20 cm long) and thicker leaves than I. panamensis .