Date of Award

Fall 1997

Project Type


Program or Major

Plant Biology

Degree Name

Doctor of Philosophy

First Advisor

Garrett E Crow


The genus Nuphar (Nymphaeaceae) comprises 10 perennial species native to freshwaters of the Northern Hemisphere. This taxonomic assessment utilizes morphometric analyses, cladistic analyses of morphology, nuclear and chloroplast DNA sequences, evaluation of randomly amplified polymorphic DNA, and pollen fertility estimations. Evolutionary reconstructions position Nuphar at the base of the family, most closely allied to Barclaya. Phylogenetic estimates within Nuphar indicate two major evolutionary lines, largely congruent with present biogeographical distributions that indicate an Old World/New World divergence. Accordingly, the genus is subdivided into two sections, Nuphar and Astylata. Section Nuphar includes the type of the genus, N. lutea, as well as N. pumila, N. japonica, N. xintermedia of Eurasia, and N. microphylla of northeastern North America; sect. Astylata comprises N. advena, N. polysepala, N. sagittifolia, N. variegata, and N. xrubrodisca, all confined to North America. Hybridization events within and between these sections are evident. All studies illustrate high morphological variability and close relationships of species within each section. The biology of Nuphar is summarized and a comprehensive taxonomic treatment is presented.