About

Norman Douglas is an Associate Instructional Professor in the Department of Biology at the University of Florida. He holds a Ph.D. from Duke University, earned in 2007. His research interests include plant systematics and phylogeography. In addition to his research, he serves as the Undergraduate Coordinator for the Botany, Zoology, and Marine Science majors, providing advising sessions primarily on Tuesdays via Zoom or by prior arrangement. His contact information includes an email address (nadouglas@ufl.edu), phone number (352-294-2842), and office location in 618A Carr Hall. Norman Douglas is actively involved in teaching and advising within the College of Liberal Arts and Sciences.

Research topics

• Botany
• Evolutionary biology
• Biology
• Anatomy
• Anthropology
• Ecology

Selected publications

• A phylogeny of the evening primrose family (Onagraceae) using a target enrichment approach with 303 nuclear loci

  BMC Ecology and Evolution · 2023-11-17 · 11 citations

  articleOpen access

  BACKGROUND: The evening primrose family (Onagraceae) includes 664 species (803 taxa) with a center of diversity in the Americas, especially western North America. Ongoing research in Onagraceae includes exploring striking variation in floral morphology, scent composition, and breeding system, as well as the role of these traits in driving diversity among plants and their interacting pollinators and herbivores. However, these efforts are limited by the lack of a comprehensive, well-resolved phylogeny. Previous phylogenetic studies based on a few loci strongly support the monophyly of the family and the sister relationship of the two largest tribes but fail to resolve several key relationships. RESULTS: We used a target enrichment approach to reconstruct the phylogeny of Onagraceae using 303 highly conserved, low-copy nuclear loci. We present a phylogeny for Onagraceae with 169 individuals representing 152 taxa sampled across the family, including extensive sampling within the largest tribe, Onagreae. Deep splits within the family are strongly supported, whereas relationships among closely related genera and species are characterized by extensive conflict among individual gene trees. CONCLUSIONS: This phylogenetic resource will augment current research projects focused throughout the family in genomics, ecology, coevolutionary dynamics, biogeography, and the evolution of characters driving diversification in the family.

  PublisherOA PDFDOI

• Target Enrichment and Extensive Population Sampling Help Untangle the Recent, Rapid Radiation of <i>Oenothera</i> Sect. <i>Calylophus</i>

  Systematic Biology · 2022 · 18 citations

  • Biology
  • Evolutionary biology
  • Botany

  Oenothera sect. Calylophus is a North American group of 13 recognized taxa in the evening primrose family (Onagraceae) with an evolutionary history that may include independent origins of bee pollination, edaphic endemism, and permanent translocation heterozygosity. Like other groups that radiated relatively recently and rapidly, taxon boundaries within Oenothera sect. Calylophus have remained challenging to circumscribe. In this study, we used target enrichment, flanking noncoding regions, gene tree/species tree methods, tests for gene flow modified for target-enrichment data, and morphometric analysis to reconstruct phylogenetic hypotheses, evaluate current taxon circumscriptions, and examine character evolution in Oenothera sect. Calylophus. Because sect. Calylophus comprises a clade with a relatively restricted geographic range, we were able to extensively sample across the range of geographic, edaphic, and morphological diversity in the group. We found that the combination of exons and flanking noncoding regions led to improved support for species relationships. We reconstructed potential hybrid origins of some accessions and note that if processes such as hybridization are not taken into account, the number of inferred evolutionary transitions may be artificially inflated. We recovered strong evidence for multiple evolutionary origins of bee pollination from ancestral hawkmoth pollination, edaphic specialization on gypsum, and permanent translocation heterozygosity. This study applies newly emerging techniques alongside dense infraspecific sampling and morphological analyses to effectively reconstruct the recalcitrant history of a rapid radiation. [Gypsum endemism; Oenothera sect. Calylophus; Onagraceae; phylogenomics; pollinator shift; recent radiation; target enrichment.].

  PublisherOA PDFDOI

• Target enrichment and extensive population sampling help untangle the recent, rapid radiation of <i>Oenothera</i> sect. <i>Calylophus</i>

  bioRxiv (Cold Spring Harbor Laboratory) · 2021-02-20 · 2 citations

  preprintOpen access

  ABSTRACT Oenothera sect. Calylophus is a North American group of 13 recognized taxa in the evening primrose family (Onagraceae) with an evolutionary history that may include independent origins of bee pollination, edaphic endemism, and permanent translocation heterozygosity. Like other groups that radiated relatively recently and rapidly, taxon boundaries within Oenothera sect. Calylophus have remained challenging to circumscribe. In this study, we used target enrichment, flanking non-coding regions, summary coalescent methods, tests for gene flow modified for target-enrichment data, and morphometric analysis to reconstruct phylogenetic hypotheses, evaluate current taxon circumscriptions, and examine character evolution in Oenothera sect. Calylophus . Because sect. Calylophus comprises a clade with a relatively restricted geographic range, we were able to extensively sample across the range of geographic and morphological diversity in the group. We found that the combination of exons and flanking non-coding regions led to improved support for species relationships. We reconstructed potential hybrid origins of some accessions and note that if processes such as hybridization are not taken into account, the number of inferred evolutionary transitions may be artificially inflated. We recovered strong evidence for multiple origins of the evolution of bee pollination from ancestral hawkmoth pollination, the evolution of edaphic specialization on gypsum, and permanent translocation heterozygosity. This study applies newly emerging techniques alongside dense infraspecific sampling and morphological analyses to effectively address a relatively common but recalcitrant problem in evolutionary biology.

  PublisherOA PDFDOI

• Diversity, distribution, development, and evolution of medullary bundles in Nyctaginaceae

  American Journal of Botany · 2020 · 14 citations

  • Biology
  • Evolutionary biology
  • Botany

  PREMISE: Medullary bundles, i.e., vascular units in the pith, have evolved multiple times in vascular plants. However, no study has ever explored their anatomical diversity and evolution within a phylogenetic framework. Here, we investigated the development of the primary vascular system within Nyctaginaceae showing how medullary bundles diversified within the family. METHODS: Development of 62 species from 25 of the 31 genera of Nyctaginaceae in stem samples was thoroughly studied with light microscopy and micro-computed tomography. Ancestral states were reconstructed using a maximum likelihood approach. RESULTS: Two subtypes of eusteles were found, the regular eustele, lacking medullary bundles, observed exclusively in representatives of Leucastereae, and the polycyclic eustele, containing medullary bundles, found in all the remaining taxa. Medullary bundles had the same origin and development, but the organization was variable and independent of phyllotaxy. Within the polycyclic eustele, medullary bundles developed first, followed by the formation of a continuous concentric procambium, which forms a ring of vascular bundles enclosing the initially formed medullary bundles. The regular eustele emerged as a synapomorphy of Leucastereae, while the medullary bundles were shown to be a symplesiomorphy for Nyctaginaceae. CONCLUSIONS: Medullary bundles in Nyctaginaceae developed by a single shared pathway, that involved the departure of vascular traces from lateral organs toward the pith. These medullary bundles were encircled by a continuous concentric procambium that also constituted the polycyclic eustele, which was likely a symplesiomorphy for Nyctaginaceae with one single reversion to the regular eustele.

  PublisherDOI

• Clarifying generic delimitation in Nyctaginaceae tribe Pisonieae after more than a century of taxonomic confusion

  Botanical Journal of the Linnean Society · 2019-01-05 · 10 citations

  article

  After more than a century of taxonomic confusion in Nyctaginaceae tribe Pisonieae, we aim to clarify relationships in the tribe by analysing combined sequences of nuclear ribosomal ITS and plastid intron rps16 using phylogenetic analyses based on parsimony and Bayesian inference and performing ancestral character estimates of morphological traits traditionally used in the tribe. Results could be used as the basis for taxonomic restructuring of this notoriously complicated group, suggesting that Pisonieae are subdivided into three distinct lineages, clades A, B and C. Clade A comprises species with pedicellate flowers of Pisoniella, Pisonia section Prismatocarpae and P. section Timeroya, and clades B and C comprise species with sessile flowers of P. section Pisonia (clade B) and P. section Paucistaminatae (P. sandwicensis), Guapira and Neea (Clade C). In addition, results indicate that exserted stamens are highly homoplastic in the Guapira/Neea lineage, whereas dry anthocarps with conspicuous glandular emergences are ancestral in Pisonieae. We recommend that Pisonia should be recircumscribed to correspond to clade B, which includes the type species of the genus (although the topology would also allow for recognition of Pisonia s.l.). Neea should be synonymized under Guapira. Ceodes and Rockia merit generic resurrection.

  PublisherDOI

• What are the "sticky rings" on stems of Anulocaulis and related taxa (Nyctaginaceae) from arid regions?

  Journal of the Botanical Research Institute of Texas · 2019-10-31 · 3 citations

  articleOpen accessSenior author

  Anulocaulis, commonly known as “ringstem,” is a small, unusual genus restricted to the Chihuahuan, Sonoran, and Mojave deserts of North America. Here we combined light microscopy and histochemical tests to characterize for the first time the “sticky structures” (here called secretory rings) found on the stem internodes of Anulocaulis. The secretory rings were shown to be groups of epidermal cells, or unicellular glandular trichomes, which largely differ from their neighboring cells both in structure and histochemistry. The cells start to differentiate in early stages of stem development. They begin as regular epidermal cells, but later their anticlinal and external tangential walls start to enlarge. At maturity the cells become remarkably elongated, even balloon-like, with dense cytoplasmic content. Although the secretory rings have been reported as “mucilaginous structures” based on morphological observations, preliminary histochemical analyses showed that its exudate is complex, including a mixture of mucilage, proteins, and phenolic compounds. Future investigations are needed to compare the anatomy of the secretory rings within related genera of Nyctaginaceae and characterize the chemical components of their exudate more specifically to search for potential homologies and adaptive functions of these structures.

  PublisherDOI

• Plastid phylogenomic insights into the evolution of Caryophyllales

  Molecular Phylogenetics and Evolution · 2019-02-05 · 210 citations

  article
  PublisherDOI

• Disparity, Diversity, and Duplications in the Caryophyllales

  bioRxiv (Cold Spring Harbor Laboratory) · 2017-05-01 · 8 citations

  preprintOpen access

  Summary The role whole genome duplication (WGD) plays in the history of lineages is actively debated. WGDs have been associated with advantages including superior colonization, various adaptations, and increased effective population size. However, the lack of a comprehensive mapping of WGDs within a major plant clade has led to uncertainty regarding the potential association of WGDs and higher diversification rates. Using seven chloroplast and nuclear ribosomal genes, we constructed a phylogeny of 5,036 species of Caryophyllales, representing nearly half of the extant species. We phylogenetically mapped putative WGDs as identified from analyses on transcriptomic and genomic data and analyzed these in conjunction with shifts in climatic niche and lineage diversification rate. Thirteen putative WGDs and twenty-seven diversification shifts could be mapped onto the phylogeny. Of these, four WGDs were concurrent with diversification shifts, with other diversification shifts occurring at more recent nodes than WGDs. Five WGDs were associated with shifts to colder climatic niches. While we find that many diversification shifts occur after WGDs it is difficult to consider diversification and duplication to be tightly correlated. Our findings suggest that duplications may often occur along with shifts in either diversification rate, climatic niche, or rate of evolution.

  PublisherOA PDFDOI

• Disparity, diversity, and duplications in the Caryophyllales

  New Phytologist · 2017-09-11 · 93 citations

  articleOpen access

  The role played by whole genome duplication (WGD) in plant evolution is actively debated. WGDs have been associated with advantages such as superior colonization, various adaptations, and increased effective population size. However, the lack of a comprehensive mapping of WGDs within a major plant clade has led to uncertainty regarding the potential association of WGDs and higher diversification rates. Using seven chloroplast and nuclear ribosomal genes, we constructed a phylogeny of 5036 species of Caryophyllales, representing nearly half of the extant species. We phylogenetically mapped putative WGDs as identified from analyses on transcriptomic and genomic data and analyzed these in conjunction with shifts in climatic occupancy and lineage diversification rate. Thirteen putative WGDs and 27 diversification shifts could be mapped onto the phylogeny. Of these, four WGDs were concurrent with diversification shifts, with other diversification shifts occurring at more recent nodes than WGDs. Five WGDs were associated with shifts to colder climatic occupancy. While we find that many diversification shifts occur after WGDs, it is difficult to consider diversification and duplication to be tightly correlated. Our findings suggest that duplications may often occur along with shifts in either diversification rate, climatic occupancy, or rate of evolution.

  PublisherOA PDFDOI

• A new resource for the development of SSR markers: Millions of loci from a thousand plant transcriptomes

  Applications in Plant Sciences · 2016-06-01 · 36 citations

  articleOpen access

  PREMISE OF THE STUDY: The One Thousand Plant Transcriptomes Project (1KP, 1000+ assembled plant transcriptomes) provides an enormous resource for developing microsatellite loci across the plant tree of life. We developed loci from these transcriptomes and tested their utility. METHODS AND RESULTS: Using software packages and custom scripts, we identified microsatellite loci in 1KP transcriptomes. We assessed the potential for cross-amplification and whether loci were biased toward exons, as compared to markers derived from genomic DNA. We characterized over 5.7 million simple sequence repeat (SSR) loci from 1334 plant transcriptomes. Eighteen percent of loci substantially overlapped with open reading frames (ORFs), and electronic PCR revealed that over half the loci would amplify successfully in conspecific taxa. Transcriptomic SSRs were approximately three times more likely to map to translated regions than genomic SSRs. CONCLUSIONS: We believe microsatellites still have a place in the genomic age-they remain effective and cost-efficient markers. The loci presented here are a valuable resource for researchers.

  PublisherOA PDFDOI

Frequent coauthors

• Pamela S. Soltis

  Florida Museum of Natural History

  16 shared

• Norman J. Wickett

  Clemson University

  10 shared

• Michael J. Moore

  10 shared

• Krissa A. Skogen

  Clemson University

  10 shared

• Jeremie B. Fant

  Brooklyn Botanic Garden

  9 shared

• Rick Overson

  Arizona State University

  7 shared

• Matthew G. Johnson

  Texas Tech University

  7 shared

• Benjamin J. Cooper

  Prisma Health

  6 shared

Education

• PhD, Biology

  Duke University

  2007

• B.Sc., Ecology & Evolutionary Biology

  University of Arizona

  1995