Abstract Detail


Baniaga, Anthony [1], Spriggs, Elizabeth [2], Edwards, Erika [2], Donoghue, Michael [2].

Polyploidy underlies morphological and ecological diversity in the taxonomically difficult Viburnum dentatum species complex of eastern North America.

The Viburnum dentatum species complex (Adoxaceae) is a clade of several closely related lineages that exhibit complex patterns of geographical, morphological, and molecular variation. Populations are widely distributed throughout a variety of microhabitats (mesic forests, wetlands, sand dunes) from eastern Texas across to Florida and northward to Nova Scotia. Across this range, populations are highly variable in leaf size, shape, toothiness, pubescence, and the timing of leaf emergence, and on this basis between two and thirteen taxa have been recognized by various authors. Previous work in this system hinted at geographically structured chromosome number variation within the complex, there being both tetrapoloids and octoploids. Over the past several years we have collected extensively across the range of the complex and coupled morphological measurements with RAD-sequencing, flow cytometry, and anatomical studies. Recently we have concentrated in the northeastern USA on the distinction that has been made between the widespread V. recognitum and V. venosum, which is largely endemic to the Long Island-Cape Cod coastal islands and lowlands. Originally described from Nantucket Island, at times V. venosum has been treated at the rank of species, has had several different varieties of it recognized, and has been treated at the rank of variety belonging to the V. scabrellum lineage. We have found that V. recognitum plants are tetraploids, while plants matching V. venosum are octoploids.  We show that octoploidy is correlated with more robust plants with larger leaves, stellate pubescence, and more marginal leaf teeth. Several anatomical traits are also correlated, such as larger and less dense stomatal guard cells in the octopoloids. Tetraploid and octoploid plants are comingled in several localities, which raises questions about the factors that maintain these two forms. Differences in the timing of flowering may favor assortative mating and in turn may promote the differentiation of these two cytotypes. We hypothesize that the same factors may explain the differences observed across the entire range of the V. dentatum complex.  

1 - Yale University, Ecology & Evolutionary Biology, 165 Prospect Street, New Haven, CT, 06511, USA
2 -
3 - Yale University, Department Of Ecology And Evolutionary Biology, 165 Prospect St, New Haven, CT, 06511, United States
4 - Yale University, Department Of Ecology And Evolutionary Biology, 21 Sachem Street, Po Box 208106, New Haven, CT, 06511, United States

Cytotype Coexistence
Coastal Islands
Viburnum dentatum

Presentation Type: Oral Paper
Session: ECOPH3, Ecophysiology III
Location: Virtual/Virtual
Date: Thursday, July 30th, 2020
Time: 3:15 PM
Number: ECOPH3002
Abstract ID:183
Candidate for Awards:None

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