To lump or to split? Revision of Cuscuta section Indecorae using a combined morphometric, phylogenetic and host range approach

Cuscuta section Indecorae is an infrageneric clade of subgenus Grammica that originated in N America which includes three species: C. indecora, C. coryli, and C. warneri. Some forms of C. indecora are agricultural weeds, while C. warneri and C. coryli face conservation problems regionally or globally. Cuscuta indecora is a morphologically diverse species with three recognized varieties: indecora, longisepala, and attenuata. Two recent broad-scale molecular phylogenetic studies raised questions about the circumscription of C. indecora and the validity of its infraspecific taxa. Therefore, we conducted an extensive morphometric study and used DNA sequences from plastid and nuclear ribosomal non-coding regions to reconstruct evolutionary relationships among taxa. In addition, we studied the host range of all taxa using herbarium specimens, bipartite networks, and Venn diagrams. Results from all types of evidence confirmed the circumscription of the three species but differed on the infrasp..., 1) Section_sect_Indecorae_MORPHOMETRIC-matrix. A total of 47 morphological characters were measured/scored using rehydrated plant material from 188 herbarium specimens. A total of 47 morphological characters were measured/scored (see article and Readme file). Empty cells in the Excel spreadsheet represent missing data for that particular trait and specimen. The extent of morphological variation was visualized with both principal coordinates analysis (PCoA or multidimensional scaling) and unweighted pair-group average (UPGMA), using the Gower’s coefficient of similarity.
2). Cuscuta-sect-indecorae-host-matrix. 964 herbarium specimens for which the host plants could be identified at species, genus, or family level were used to calculate a HFI index at these three taxonomic levels. The HFI shows the frequency (percentage) of a Cuscuta taxon to be encountered on a particular host (at family, genus, and species level), in relation to the total number of host occurrences. HFI data were then m..., , # To lump or to split? Revision of *Cuscuta* section *Indecorae* using a combined morphometric, phylogenetic and host range approach

[https://doi.org/10.5061/dryad.p8cz8wb02](https://doi.org/10.5061/dryad.p8cz8wb02)

## Description of the data and file structure

Two Excel files are included:

**1) Section_sect_Indecorae_MORPHOMETRIC-matrix (Morphology and Morphometric Analyses)**

This is the full dataset consisting of an Excel spreadsheet that includes all measurements and scores for 47 characters (columns) obtained from 188 herbarium specimens (lines) representing the taxa of sect. *Indecorae*. See more details about the rehydration of specimens and microscopy in the article. **Empty cells in the Excel spreadsheet represent missing data (\"gaps\") for those herbarium specimens and characters specific values could not be obtained**.

The characters measured/scored were:

*Continuous Characters.*

Pedicel length (mm)
Bract length (mm).
Bract width (measured at the base, mm).
Angle of...