Abstract Detail

Systematics Section/ASPT

Larsén, Eva [1], Rydin, Catarina [2].

Disentangling the phylogeny of Isoetes.

Isoetes is a genus of heterosporous lycopsids with around 150-200 extant species with cosmopolitan distribution. It is the only remaining representative of the rhizomorphic lycopsids, an ancient clade that historically was more diverse and includes the famous tree lycopods from the Carboniferous period, such as Lepidodendron. The modern species have a reduced plant body with very restricted apical growth and occur either fully submerged or in semi-aquatic habitats, but a few terrestrial species also exist. There is very little morphological and molecular divergence between species, despite the worldwide distribution and probable Palaeozoic origin of the family. Phylogenetic analysis of the genus based on molecular data has been further complicated by the distant relationship to the sister group Selaginella. And despite efforts to determine the relationships between Isoetes species based on morphology and molecular data, the phylogeny, biogeography, and divergence times of clades within the genus are still not well understood. We add to the previous endeavours and I will discuss the major relationships within Isoetes and a first assessment of divergence times of clades. The results indicate that the crown group is surprisingly old, despite the low molecular and morphological divergence among species.

1 - Stockholm University, Department of Ecology, Environment and Plant Sciences, Lilla Frescativägen 5, Stockholm, SE-106 91, Sweden
2 - Stockholm University, Department of Ecology, Environment and Plant Sciences, Lilla Frescati 5, Stockholm, 10691, Sweden

Keywords:
Isoetes
Phylogeny
molecular dating.

Presentation Type: Oral Paper:Papers for Sections
Session: 33
Location: Salon 10/The Shaw Conference Centre
Date: Tuesday, July 28th, 2015
Time: 8:15 AM
Number: 33002
Abstract ID:827
Candidate for Awards:None