Systematics of the northern Andean Isoetes karstenii complex

The Isoetes karstenii complex includes those species characterized by laevi gate megaspores, acute to free ala apices, a highly reduced labium, and dis tributions in the high altitude paramos of Venezuela, Colombia, and Ecuador . These species have been variously treated in the literature. Many early a uthors placed all Andean laevigate-spored specimens in Isoetes lechleri, a central Andean species, while one later author recognized up to eight north ern Andean species distinct from I. lechleri. This research represents a re visionary study to determine the number and identity of the taxa in this co mplex. Multivariate and descriptive analyses of morphological data and chro mosome counts were performed. Five species axe recognized including the pre viously described I. karstenii and I. palmeri. One variety is transferred f rom I. lechleri to I. karstenii (I. karstenii var. anomala). Three of the r ecognized species are newly described: I. fuliginosa, I. hemivelata and I. precocia. Chromosome counts revealed that I. karstenii and I. precocia are diploids (2n = 22) and that I. palmeri is tetraploid (2n = 44). Estimates o f chromosome number based on spore size for I. fuliginosa and I. hemivelata indicate that they are polyploid (2n greater than or equal to 44).