Cryptic speciation in allotetraploids: Lessons from the Botrychium matricariifolium complex

Area of Science:

• Botany
• Genetics
• Taxonomy

Background:

• Cryptic species pose challenges for botanists and taxonomists.
• The genus Botrychium (Ophioglossaceae) exhibits instances of allopolyploid speciation.
• Improving species delineation in Botrychium is crucial for understanding plant diversity.

Purpose of the Study:

• To improve species delineation within the Botrychium genus.
• To investigate a cryptic species complex in Botrychium using genetic and morphological data.
• To determine if distinct morphotypes warrant taxonomic recognition.

Main Methods:

• Sampling across the B. matricariifolium complex in Michigan.
• Allozyme electrophoresis (10 enzyme systems) on over 1500 samples.
• Morphological character analysis (42 traits) on over 650 individuals.
• Amplified Fragment Length Polymorphism (AFLP) analysis on 145 samples.

Main Results:

• Allozyme variation partially correlated with B. matricariifolium morphotypes.
• B. michiganense possesses unique alleles, suggesting a distinct hybrid origin.
• Genetic distinction between B. matricariifolium and B. michiganense was greater than within B. matricariifolium morphotypes.

Conclusions:

• B. acuminatum is taxonomically within B. matricariifolium.
• B. matricariifolium and B. michiganense likely arose from hybridization events.
• Morphotypes within B. matricariifolium result from repeated hybridization between the same parental species.
• Genetic analyses aid in resolving field-observed morphological variation.