Keir Wefferling

So it’s true, I do love reticulate complexes, preferably allopolyploid and usually more or less sessile. While my published work to date has been on flowering plants (moonseeds and buttercup relatives mostly), I am diving headlong into the wonderful (and terrifying) world of seed-free plants; in particular Pteridaceae, in more particular cheilanthoid ferns, in very particular Pentagramma,  the xeric-adapted, farinose goldback and silverback ferns (see Schuettpelz et al. 2015 for an excellent background and summary of the systematics within this western North American genus).

While working as a postdoc here in the Rothfels lab, I will study the cytogeography, biochemistry, and systematics of Pentagramma across their geographic range, and query the polyploid “spectrum” (i.e., the range between the extremes of auto- and allopolyploids). I aim to test the hypothesis that there is a particular genetic distance between parents that is optimal for formation of evolutionarily “successful” offspring; i.e., that a goldilocks zone exists (Sessa et al. 2012), at least within a particular lineage. Wish me luck!


Schuettpelz E, Pryer KM, Windham MD (2015) A unified approach to taxonomic delimitation in the fern genus Pentagramma (Pteridaceae). Systematic Botany 40:629–644.

Sessa EB, Zimmer EA, Givnish TJ (2012) Unraveling reticulate evolution in North American Dryopteris (Dryopteridaceae). BMC Evolutionary Biology 12:104.

Just outside Lassen NP, locating the not-so-elusive Caltha biflora!

Please see my webpage for more information on my interests and research questions, outreach activities, or my Google Scholar page.

Reach me at keirwefferling [at]


Peer-reviewed publications


Wefferling KM, Hoot SB (2018) Dated phylogeography of western North American subalpine marshmarigolds (Caltha spp., Ranunculaceae): Miocene-Pliocene divergence of hexaploids, multiple origins of allododecaploids during the Pleistocene, and repeated recolonization of Last Glacial Maximum glaciated regions. Journal of Biogeography 45:1077–1089. doi:


Wefferling KM, Hoot SB (2017) Species circumscription of the Caltha leptosepala polyploid complex (Ranunculaceae) based on molecular and morphological data. Phytotaxa 316:201–223. doi:

Wefferling KM, Castro S, Loureiro J, Castro M, Tavares D, Hoot SB (2017) Cytogeography of the subalpine marsh marigold polyploid complex (Caltha leptosepala s.l.). American Journal of Botany 104:271–285. doi:

2015 and earlier

Wefferling KM, Owen HA, Hoot SB (2015) Caltha leptosepala DC. In: Marhold, K. (ed.), IAPT/IOPB chromosome data 20. Taxon 64:1350, E36–E39. doi:

Hoot SB, Wefferling KM, Wulff JA (2015) Phylogeny and character evolution of Papaveraceae s. l. (Ranunculales). Systematic Botany 40:474–488. doi:

Wefferling KM, Hoot SB, Neves SS (2013) Phylogeny and fruit evolution in Menispermaceae. American Journal of Botany 100:883–905. doi: 10.3732/ajb.1200556

Herrera F, Manchester SR, Hoot SB, Wefferling KM, Carvalho MR, Jaramillo C (2011) Phytogeographic implications of fossil endocarps of Menispermaceae from the Paleocene of Colombia. American Journal of Botany 98:2004–2017. doi: 10.3732/ajb.1000461

Other publications

Wefferling KM, Hoot SB (2014) Disentangling the mountain marsh-marigold species complex: Speciation and hybridization in Caltha leptosepala sensu lato (Ranunculaceae). Douglasia 38: 4–9.