Draining the swamp dodders: Systematics of Cuscuta gronovii s.l. (subgenus Grammica, sect. Oxycarpae)
Creators: name: Costea, Mihai
name: Wright, Michael
name: Glofcheskie, Morgan
name: Genter, Wade
name: Stefanović, Saša
Publisher: name: Zenodo
Year: 2023
Subjects: atypical pollen grains
Morphometry
new species
parasitic plants
molecular phylogeny
swamp dodder
Weed
Cuscuta gronovii
Convolvulaceae

description: <em>Cuscuta</em> <em>gronovii</em> species complex (sensu lato, s.l.) is a North American group of species that belong to sect. <em>Oxycarpae</em> of subgenus Grammica. Members of <em>C</em>. <em>gronovii</em> s.l. are often associated with riparian or wet habitats, and their delimitation has been problematic historically. DNA sequences from multiple plastid and nuclear ribosomal non-coding regions were used to reconstruct evolutionary relationships among taxa. Molecular phylogeny supported the resurrection of <em>C</em>. <em>saururi</em>, a taxon that has been treated either as <em>C</em>. <em>gronovii</em> var. <em>latiflora</em> or a nomenclatural synonym of <em>C.</em> <em>gronovii</em> var. <em>gronovii</em>. <em>Cuscuta</em> <em>saururi</em> was inferred to be sister to <em>C. cephalanthi</em>, but the relationships among the rest of taxa, although forming a clade with a moderate support, remained largely unresolved. Thus, the species limits of <em>C. gronovii</em> s.l. aggregate were also comprehensively investigated through a morphometric study. Plants with 4-merous flowers from New Brunswick and Nova Scotia, Canada, which were previously thought to be <em>C. cephalanthi</em>, were described as a new species, <em>C. acadiana</em>. <em>Cuscuta</em> <em>acadiana</em>, although fertile and producing abundant seeds, is unusual in that the majority of its pollen grains intergrade from zonocolpate, syncolpate or pantocolpate, with variously shaped or twisted ectoapertures. <em>Cuscuta gronovii</em> var. <em>calyptrata</em>, a widely accepted but virtually unknown taxon, was typified and included in all the analyses. <em>Cuscuta</em> <em>umbrosa</em> was treated as a variety of <em>C. gronovii</em> (var. <em>curta</em>), and <em>C. rostrata</em> was maintained as a species. An identification key, detailed descriptions, illustrations, and a summary of geographical distribution, ecology and conservation status were provided for all the members of <em>C. gronovii</em> s.l. The only taxon of this species complex found to be weedy, especially in cranberries, was <em>C. gronovii </em>var. <em>gronovii</em>.
description: Excel and Word (Microsoft).Funding provided by: Natural Sciences and Engineering Research Council of Canada<br>Crossref Funder Registry ID: http://dx.doi.org/10.13039/501100000038<br>Award Number: 327013Funding provided by: Natural Sciences and Engineering Research Council of Canada<br>Crossref Funder Registry ID: http://dx.doi.org/10.13039/501100000038<br>Award Number: 326439
description: The dataset consists of 47 characters measured or scored from rehydrated and dissected flowers, fruits and seeds of seven <em>Cuscuta</em> taxa. 200 herbarium specimens deposited in different herbaria from North America were used for this purpose (For full details of the specimens see Appendix 1 in the article). This Dryad submission also includes: - One supplementary table (Table S1); - Theree supplementary figures (Figs. S1, S2, S3). For more details, see the article.