HOGGARD, RON1*, PAUL KORES1, MIA MOLVRAY1, GLORIA HOGGARD1, and DAVID BROUGHTON2. 1Department of Botany and Microbiology, University of Oklahoma, Norman, OK 73019; 2Department of Applied Plant Science, The Queen's University of Belfast, Belfast, BT9 5PX. - Molecular systematics and biogeography of the amphibious genus Littorella (Plantaginaceae).
Littorella is a small, amphibious genus within the
Plantaginaceae and is represented by three closely related, disjunct
species, L. uniflora (L.) Ascherson in Europe including
Iceland and the Azores, L. americana Fernald in North
America, and L. australis Griseb. ex Bentham & Hooker in
southern South America. A recent phylogeny (Rahn, 1996) based on
morphological, embryological, and chemical data has resulted in the
reduction of Littorella to Plantago subgenus
Littorella (P.J. Bergius) Rahn and renaming of the included
species to Plantago uniflora L. (= Littorella uniflora
(L.) Aschers.), Plantago americana (Fernald) Rahn (=
Littorella americana Fernald), and Plantago araucana
Rahn (= Littorella australis Griseb.). We compared this
phylogeny to one based on DNA sequence data from the nuclear ribosomal
internal transcribed spacer region (ITS). A total of four outgroup
taxa, three species of Littorella , and 44 species of
Plantago were included in this analysis. Our molecular phylogeny
supports the generic recognition of Littorella as it is
clearly sister to Plantago . Our phylogeny also rejects the
conspecific recognition of L. americana and L. uniflora
as proposed by recent North American authors and suggests a
European origin for Littorella .
Key words: Littorella, phylogeny, Plantaginaceae, Plantago