Publications

2023

Goniopteris ×tico (Thelypteridaceae), a new hybrid fern from Costa Rica. Elissa Sorojsrisom, Olman Alvarado-Rodríguez, Weston Testo. Systematic Botany. 48: 471–481. (PDF)

Adiantum weatherbyanum Espinosa, an overlooked species from northern Chile and A. rodriguezii, a new species from Central Chile. Jefferson Prado, Regina Hirai, Michael Sundue, Weston Testo. American Fern Journal. 113:249–256. (PDF)

Sinopsis de Selaginella (Selaginellaceae) para el departamento de Antioquia, Colombia. Susana Vega-Betancur, Ricardo Callejas, Weston Testo, Alejandra Vasco. Brittonia. online in advance of issue. (PDF)

Phylogenomic evolutionary insights in the fern family Gleicheniaceae. Lucas Lima, Alexandre Salino, Michael Kessler, Germinal Rouhan, Weston Testo, Caio Argolo, GoFlag Consortium, Thais Almeida. Molecular Phylogenetics and Evolution. 184: e107782. (PDF)

2022

Madagascar’s extraordinary biodiversity: threats and opportunities. Hélène Ralimanana, … Weston Testo,… et al. [89 authors]. Science. 378: eadf1466. (PDF)

Madagascar’s extraordinary biodiversity: evolution, distribution, and use. Alexandre Antonelli, … Weston Testo,… et al. [89 authors]. Science. 378: eabf0869. (PDF)

The relationship between chlorophyllous spores and mycorrhizal associations in ferns: Evidence from an evolutionary approach. Daniela Mellado-Mansilla, Weston Testo, Michael A. Sundue, Gerhard Zotz, Holger Kreft, Mario Coiro, Michael Kessler. American Journal of Botany. 109: 2068–2081. (PDF)

Deep vicariance and frequent transoceanic dispersal shape the evolutionary history of a globally distributed fern family. Weston Testo, André de Gasper, Sonia Molino, José María Gabriel y Galán, Alexandre Salino, Vinícius Dittrich, and Emily Sessa. American Journal of Botany. 109: 1–17. (PDF)

Hydathodes in ferns: their phylogenetic distribution, structure and function. Klaus Mehltreter, Hanna Wachter, Christophe Trabi, Weston Testo, Michael Sundue, Steven Jansen. Annals of Botany. 130: 331–344. (PDF)

Close observation of a common fern challenges long-held notions of how plants move. A commentary on ‘Fern fronds that move like pine cones: humidity-driven motion of fertile leaflets governs the timing of spore dispersal in a widespread fern species’. James Watkins, Weston Testo. Annals of Botany 129: 1–3. (PDF)

A permineralized Early Cretaceous lycopsid from China and the evolution of crown clubmosses. Fabiany Herrera, Weston Testo, Ashley Field, Elizabeth Clark, Patrick Herendeen, Peter Crane, and Gongle Shi. New Phytologist doi:10.1111/nph.17874. (PDF)

2021
A global phylogenomic study of the Thelypteridaceae. Susan Fawcett, Alan Smith, Michael Sundue, Gordon Burleigh, Emily Sessa, Li-Yaung Kuo, Cheng-Wei Chen, Weston Testo, Michael Kessler, GoFlag Consortium, and David Barrington. Systematic Botany 46: 891–915. (PDF) *Using 400+ nuclear loci from the GoFlag probe set and more than 600 samples, we resolved the phylogeny of a hyper-diverse and phenomenally challenging family of ferns. A great example of how target-capture sequence data can help us leverage herbarium specimens to resolve the evolutionary history of recalcitrant plant clades.

The Lycopodiaceae of Panamá. Benjamin Øllgaard and Weston Testo. Phytotaxa 526: 1–66. (PDF)

First record of sporangiasters in Blechnaceae. Sonia Molino, Michael Sundue, and Weston Testo. American Fern Journal 111: 196–204. (PDF)

Asplenium scolopendrium var. americanum (Aspleniaceae) found in New Mexico, USA. Weston Testo, James Watkins, JohnWiley, Laura Baumann, and Eric Weaver. American Fern Journal 111: 217–222. (PDF)

A reassessment of the little-known Amazonian fern Diplazium praestans based on molecular and morphological evidence. Lindsey Riibe, Michael Sundue, Emily Sessa, and Weston Testo. Systematic Botany 46: 260-272. (PDF)

Mountains, climate and niche heterogeneity explain global patterns of fern diversity. Jacob Suissa, Michael Sundue, and Weston Testo. Journal of Biogeography 48: 1296-1308. (PDF)

Pleistocene aridification underlies the evolutionary history of the Caribbean endemic, insular, giant Consolea (Opuntioideae). Lucas Majure, Duniel Barrios, Edgardo Díaz, Bethany Zumwalde, Weston Testo, Vivian Negrón-Ortíz. American Journal of Botany 108: 1-16. (PDF)

A target enrichment probe set for resolving the flagellate land plant tree of life. Jesse Breinholt, Sarah Carey, ... Weston Testo, ..., and J. Gordon Burleigh [26 authors]. Applications in Plant Sciences 2021: e11406. (PDF)
*This is the pilot paper for the Genealogy of Flagellate Plants project, which was the focus of my postdoc at the University of Florida. In this paper we present the GoFlag 451 and GoFlag 408 probe sets, which are powerful new parts of the plant phylogenomics toolkit. These probes target hundreds of exons and flanking non-coding regions in low-copy nuclear loci, and the probe set can be used across land plants, covering 450 MY++ of evolution! If you have any questions about the GoFlag probe set and possible applications for your research, let me know.

​Insights into the evolutionary history and widespread occurrence of antheridiogen systems in ferns. Ondrej Hornych, Weston Testo, Emily Sessa, James Watkins, Courtney Campany, Jarmila Pittermann, Libor Ekrt New Phytologist 229: 607-619. (PDF)

2020
Nuevos reportes para la flora de La Española. Lucas Majure, Teodoro Clase, Weston Testo, William Cinea, and Brígido Peguero. Moscosoa 20: 151-161. (PDF).

Celebrating David Barrington's contributions to fern and lycophyte research: introduction to an American Fern Special Issue. Weston Testo.
American Fern Journal 110: 145-150. (PDF)

New Guinea has the world's richest island flora. Rodrigo Cámara-Leret, David, Frodin ... Weston Testo, ... [99 authors]. Nature 2020:1-5. (PDF)
*A nice commentary on our article in the same issue by Vojtech Novotny and Kenneth Molem is available here

A global phylogeny of Stegnogramma ferns (Thelypteridaceae): generic and sectional revision, historical biogeography and evolution of leaf architecture. Li-Yaung Kuo, Yi-Hang Chang, Yu-Hsuan Huang, Weston Testo, Atsushi Ebihara, Germinal Rouhan, Luis Quintanilla, James Watkins, Yao Moan Huang, Fay-Wei Li. Cladistics 36: 164-183. (PDF)

2019
Proposal to conserve the name Asplenium erosum (Aspleniaceae) with a conserved type. Weston Testo. Taxon 68: 594-595. (PDF)

Using RAD data to confirm parentage of polyploids in a reticulate complex of ferns. Sylvia Kinosian, Weston Testo, Sally Chambers, and Emily Sessa. American Fern Journal 109: 267-282. (PDF)

Phylogenetic and morphological analyses support the resurrection of Dendroconche and the recognition of two new genera in Polypodiaceae subfamily Microsoroideae. Weston Testo, Ashley Field, Emily Sessa, and Michael Sundue. Systematic Botany 44: 1-16. (PDF)
This was a really fun project to work on, and I learned a lot about this challenging subfamily of polypods!

The rise of the Andes promoted rapid diversification in Neotropical Phlegmariurus (Lycopodiaceae). Weston Testo, Emily Sessa, and David Barrington. New Phytologist 222: 603-613. (PDF)
*Also, a really nice commentary on our article in the same issue by lobeliologist Laura Lagomarsino, available here!

2018
Overcoming among-lineage rate heterogeneity to infer the divergence times and biogeography of the clubmoss family Lycopodiaceae. Weston Testo, Ashley Field, and David Barrington. Journal of Biogeography 45: 1929-1941. (PDF)

Are rates of species diversification and body size evolution coupled in the ferns? Weston Testo and Michael Sundue. American Journal of Botany 105: 525-535 (PDF) **(Invited contribution to special issue "Using and Navigating the Plant Tree of Life")
*A contribution to the ongoing debate about the importance of shifts in body size evolution as drivers of species proliferation: we find no evidence of body size evolution being correlated with rates of diversification across the ferns.

Novelties in Costa Rican Pityrogramma (Pteridaceae): a new species and a new hybrid from the Osa Peninsula. Weston Testo. American Fern Journal 108: 27-33. (PDF)

Target sequence capture of nuclear-encoded genes for ferns. Paul Wolf, Tanner Robison, Matthew Johnson, Michael Sundue, Weston Testo, Carl Rothfels. Application in Plant Sciences e01148 (PDF).

Phylogenetic systematics, morphological evolution, and natural groups in Neotropical Phlegmariurus (Lycopodiaceae). Weston Testo, Benjamin Øllgaard, Ashley Field, Thaís Almeida, Michael Kessler, David Barrington. Molecular Phylogenetics and Evolution 125:1-13 (PDF).

Geometry, allometry and biomechanics of fern leaf petioles: their significance for the evolution of functional and ecological diversity within the Pteridaceae. Jennifer Mahley, Jarmila Pittermann, Nick Rowe, Alex Baer, James Watkins, Eric Schuettpelz, James K Wheeler, Klaus Mehltreter, Michael Windham, Weston Testo, James Beck. Frontiers in Plant Sciences 9: 1-16. (PDF)

2017
Diplazium hybrids involving D. plantaginifolium and D. ternatum from Mexico and Central America. Weston Testo, Michael Sundue, Alejandra Vasco. Brittonia 69: 295-306. (PDF)
*It was a lot of fun to develop the ideas presented in this paper - we describe two new hybrids in the the genus and scratch the surface of the complex history of hybridization in Diplazium. There is still a lot of work to be done on reticulate evolution in tropical ferns and lycophytes!

The evolution of aluminum accumulation in ferns and lycophytes. Marco Schmitt, Klaus Mehltreter, Michael Sundue, Weston Testo, Toshihiro Watanabe, Steven Jansen. American Journal of Botany 104: 573-583. (PDF)

Phlegmariurus lehnertii, a new name for Phlegmariurus lancifolius (Lycopodiaceae). Weston Testo. Phytotaxa 297: 289-290. (PDF)

2016
A 4000-species dataset provides new insight into the evolution of ferns. Weston Testo, Michael Sundue. Molecular Phylogenetics and Evolution 105: 200-211. (PDF)
*Using a super-matrix approach, we assembled a phylogeny that includes ca. 40% of known fern species and incorporated a large fossil dataset to infer the timing of fern diversification. I think the important take-away here is that we provide evidence that many fern groups originated earlier than previous studies had suggested - subsequent studies such as Morris et al. (PNAS, 2018) and Lehtonen et al. (Scientific Reports, 2017) have corroborated our findings, which is exciting!

Huperzia continentalis (Lycopodiaceae), a new species of gemmiferous clubmoss separated from Huperzia haleakalae. Weston Testo, Arthur Haines, Arthur Gilman. Systematic Botany 41: 894-901. (PDF)
*A simple taxonomic fix for a complex and long-standing problem. Turns out Huperzia haleakalae is a (likely extinct) Hawaiian endemic and we had been misapplying that name to North American plants for decades.

​On the widespread capacity for, and functional significance of, extreme inbreeding in ferns. Emily Sessa, Weston Testo, James Watkins. New Phytologist 211: 1108-1119. (PDF)

Molecular phylogenetics and the morphology of the Lycopodiaceae subfamily Huperzioideae supports three genera: Huperzia, Phlegmariurus and Phylloglossum. Ashley Field, Weston Testo, Peter Bostock, Joseph Holtum, Michelle Waycott. Molecular Phylogenetics and Evolution 94: 635-657. (PDF)

Parapolystichum novoguineense (comb. nov.; Dryopteridaceae) from New Guinea. Michael Sundue and Weston Testo. Phytotaxa 243: 193-196. (PDF)

A community-derived classification of extant ferns and lycophytes. Eric Schuettpelz, Harald Schneider, Alan R Smith, Peter Hovenkamp, ... Weston Testo, ... Xin-Mao Zhou [94 contributors]. Journal of Systematics and Evolution 54: 563-603. (PDF)
*It was a great pleasure to be part of this large effort, which was headed up principally by Eric Schuettpelz. Ferns and lycophytes were in need of an updated, consistent, and sensible classification system; I think we achieved that here.

2015
Morphological innovation, ecological opportunity, and the radiation of a major vascular epiphyte lineage. Michael Sundue, Weston Testo, Tom Ranker. Evolution 69: 2482-2495. (PDF)

Use of gemma characters to identify North American Huperzia (Lycopodiaceae). Art Gilman, Weston Testo. American Fern Journal 105: 145-161. (PDF)

Pteris ×caridadiae (Pteridaceae), a new hybrid fern from Costa Rica. Weston Testo, James Watkins, Jarmila Pittermann, Rehman Momin. Brittonia 67: 138-143. (PDF)

An unusual form of Huperzia selago (Lycopodiaceae) and its implications for gemma homology in the genus. Weston Testo, Lynden Gerdes. American Fern Journal 105: 123-126. (PDF)

Dynamics of asymmetrical hybridization in North American wood ferns: reconciling patterns of inheritance with gametophyte reproductive biology. Weston Testo, James Watkins, David Barrington. New Phytologist 206: 785-795. (PDF)
*Interspecies sex, pheromones, and speedy sperm!

2014
Beyond antheridiogens: chemical competition between gametophytes of Polypodium appalachianum and Polypodium virginianum. Weston Testo, Matthew Grasso, David Barrington. Journal of the Torrey Botanical Society 141: 302-312. (PDF)

Primary hemiepiphytism in Colysis ampla (Polypodiaceae) provides new insight into the evolution of growth habit in ferns. Weston Testo, Michael Sundue. International Journal of Plant Sciences 175: 526-536. (PDF)

2013
Understanding mechanisms of rarity in pteridophytes: Competition and climate change threaten the rare fern Asplenium scolopendrium var. americanum (Aspleniaceae). Weston Testo, James Watkins. American Journal of Botany 100: 2261-2270. (PDF)

2012
Influence of plant size on the ecophysiology of the epiphytic fern Asplenium auritum (Aspleniaceae) from Costa Rica. Weston Testo, James Watkins. American Journal of Botany 99: 1840-1846. (PDF)

2011
Comparative development and gametophyte morphology of the hart's-tongue fern, Asplenium scolopendrium L. Weston Testo, James Watkins. Journal of the Torrey Botanical Society 138: 400-408. (PDF)

In-situ gametophyte morphology of the tropical epiphyte Oleandra articulata. James Watkins, Weston Testo, Richard Merkhofer. American Fern Journal 101: 52-56. (PDF)