Abstract Detail

Systematics

Whitley, Breanna [1], Valencia-D., Janice [2], Garwood, Nancy [3], Neubig, Kurt [4].

Phylogenetic and morphometric analysis provides insight into the lineages of Trema micrantha (Cannabaceae).

Trema (Cannabaceae) is a pantropical genus of pioneer trees with a troublesome history of species circumscriptions. Trema micrantha, a Neotropical species, is particularly problematic because it is polyphyletic, exhibits variable leaf morphology, and occupies a wide geographic range. In this study, we sought to evaluate relationships within Trema micrantha using morphological and phylogenetic analyses. We used next generation sequencing to analyze the plastome and nuclear ribosmal cistron and measured eight leaf morphology characters for Trema micrantha accessions across its geographic range. We found that Trema micrantha is paraphyletic with respect to T. domingensis and identified six well-supported clades (designated as A, B1, B2, B3, C, and D) within Trema micrantha. Principle component analysis of leaf morphology demonstrates that clades C, D, B1, and B2 are morphologically distinct, while clade A occupies similar morphospace as B2, and B3 overlaps with B1 and B2. Despite morphological overlap in leaf morphology, clade A is differentiated by brown endocarps (compared to black in other clades) and clade B3 is geographically restricted to Panama and Costa Rica. Clade C occupies montane habitats and clade D is only known from the environs of Cusco, Peru. Within B1 and B2 there is significant morphological variation. B1 is distributed across the Caribbean and Central America, while B2 occurs throughout Central and South America. Further investigation, such as ecological niche analysis is required to more thoroughly evaluate clades B1, B2, and B3. We will use these results to guide future decisions of species circumscription in a taxonomic revision of Trema.

1 - Southern Illinois University, Department Of Plant Biology, 1125 Lincoln Dr., LSII, Room 420, Carbondale , IL, 62901, United States
2 - Southern Illinois University, School of Biological Sciences, 1125 Lincoln Dr, LS II, Room 416 , Carbondale, Illinois, 62901, United States
3 - Southern Illinois University Carbondale, School Of Biological Sciences, Life Science II - Mail Code 6509, 1125 Lincoln Dr., Carbondale, IL, 62901, United States
4 - Southern Illinois University, School Of Biological Sciences, 1125 Lincoln Dr., Life Science II, Room 420, Carbondale, IL, 62901, United States

Keywords:
none specified

Presentation Type: Oral Paper
Session: SYSTIV, Systematics IV: Eurosids & Basal Asterids
Location: Virtual/Virtual
Date: Wednesday, July 21st, 2021
Time: 3:00 PM(EDT)
Number: SYSTIV001
Abstract ID:734
Candidate for Awards:None