Isoetes orcuttii A.A.Eaton
Descripción
Rootstock bi- or trilobed; leaves ca. 10, ca. 5 cm long, pale toward bases, triangular in mid-length transection; velum covering 100% of each sporangium; sporangial walls unspotted; megaspores white to dark gray, average 250–350 µm in diameter, smooth to obscurely tuberculate with girdle smooth; microspores brown in mass, average 25–35 µm long, tuberculate; 2n=22 (USA).A
Ejemplar revisado
BCN (Orcutt s.n., 12 Apr 1886, NY; Moran 26667, CAS, MICH).A
Elevación
300 mA
Ecología y Hábitat
Vernal pools, March–April.A
Categoría IUCN
No incluidaB
Categoría NOM-059-SEMARNAT-2010
No incluidaC
Discusión taxonómica
Isoëtes orcuttii reaches the southern extent of its range in northern Baja, California. This species is distinguished from all other Mexican species by its complete velum. Occasionally, its megaspores vary in color from white to gray. Comparisons of DNA nucleotide sequences indicate that I. orcuttii and two other western North American species, I. nuttallii A. Braun and I. minima A. A. Eaton, are more closely related to Isoëtes species in the Mediterranean region than they are to other North American species.A