Rutgers New Brunswick/Piscataway Campus
Lena Struwe's Research

I am involved in several different research areas that involves plant taxonomy and biodiversity, historical biogeography, GIS, and phylogenetics, and contemporary ethnobotany, weeds, and urban botany.  A lot of my work is interdisciplinary and involves researchers from areas such as pharmacology, history, media studies, urban studies, and genomics. I have worked in several areas of the world, with emphasis on North America and Latin America, and also have been collaborating on projects in Europe, Central Asia, Africa and tropical Asia.

I have started several projects focused on urban and global weeds, these misunderstood plants that are true success stories when it comes to survival, spread, and dominance. Within this area I focus on our love-hate of weeds, the evolutionary and ecological processes affecting urban weeds, the biodiversity of weeds in cities, the opinions and symbolic value of weeds in different cultures worldwide, and of course, edible and toxic weeds.  I also use weeds as an important teaching tool since it is an easily accessible resource for plant biology, evolution, and ethnobotany studies in any school area, urban to rural, and from pre-kindergarten children to senior citizens.



My second research focus is contemporary ethnobotany; how humanity use plants in our lives. I have worked with the development of sustainable use of plants for medicinal research on an international scale through the projects of ICBG Central Asia (until 2008) and GIBEX. We investigated new plants for medicinal use, based on old traditions and scientifically investigate their phytochemical content, variation, and safety. I teach several courses in this area and provide research related to medicinal plants, the need for quality control and vouchering in pharmaceutical research and commercial products based on wild (or cultivated) plants, and much more.



The research area that I have worked with since an undergraduate student is the historical evolution and biodiversity of angiosperms, especially plants from the order Gentianales and its families Apocynaceae (dogbanes and milkweeds), Gelsemiaceae (Carolina jessamine), Gentianaceae (gentians), Loganiaceae (strychnine family), and to a lesser degree Rubiaceae (coffee and madder family). I am investigating species diversity, evolution, and biogeography based on phylogenetic reconstructions using anatomical, morphological, and molecular data. Much of my recent work has focused on the classification and phylogeny of the families Gentianaceae and Loganiaceae, for which I have provided the most recent worldwide family classifications. The gentian family is also the focus of my research in the evolution of morphology and New World biogeography.
    This means that I look at a group of plants and track their ancestors and changes in their looks and attributes through their evolution tens of millions of years into the past. How old are these species? Where did they evolve?  How did they get there?  Which traits have they inherited from their ancestors?  Why do they look like this? How did their looks become like this? How do their flowers and fruits develop? What are their proper names and how many species are there out there?  Are they endangered?  How are they useful to humans? Why do some grow in the mountains and some in the rainforests or on savannas?
    I study these questions using modern molecular (DNA) and traditional (morphological) techniques. This requires field work for collecting new plant material, visits to herbaria in many countries to study specimens collected during the last 300 years, and work in my laboratory with DNA sequencing, herbarium material, computers, and microscopes. We also use methodologies such as histological preparations, SEM, GIS, statistical methods (multivariate statistics, etc.), light microscopy, phylogenetic analyses (parsimony, Bayesian, and maximum likelihood), and DNA sequencing.
As part of my research I have developed the method Spatial Evolutionary and Ecological Vicariance Analysis (SEEVA) with collaborators.

            My systematic botany research focus mainly on the evolution and biogeography in the flowering plant order Gentianales, which includes:

         The gentians (Gentianaceae)

         The strychnine family (Loganiaceae)

         The false or yellow jessamine family (Gelsemiaceae)

         The milkweeds and dogbanes (Apocynaceae, including Asclepiadaceae)

         The coffee and quinine family (Rubiaceae)

More specifics on my taxonomic research in Gentianales:

The gentian family (Gentianaceae)

Commonly known gentians are the deep-blue flowered alpine gentians (Gentiana), the pink-flowered centaury (Centaurium) and marsh-pink (Sabatia), as well as the cut flowers and potted plants of lisianthus (Eustoma) and Persian violet (Exacum).  I am using phylogenetic data from gentians to understand the biogeography of plants from tropical areas, especially in Latin America (the Neotropics).  The gentian family comprises ca. 87 genera and ca. 1650 species classified in six tribes.  It is distributed worldwide, but has the highest number of genera and greatest morphological diversity in the tropical areas of the world.  My research includes phylogenetic, biogeographic, taxonomic, and floristic projects using data derived from molecular, morphological, and anatomical studies (e.g., flower anatomy and development, palynology, seed anatomy, and DNA sequencing).

Publications: Struwe & Albert, 2002

Classification and monograph of the gentian family

The book Gentianaceae - Systematics and Natural History (Struwe & Albert, 2002) included chapters written by experts on evolution, biogeography, and morphological and molecular-based phylogenetic studies, phytochemistry and pharmacology, seed anatomy, and palynology. The book also included a new family-level classification of the gentians written in collaboration with Victor Albert, Joachim Kadereit, Jens Klackenberg, the late Siwert Nilsson, Mike Thiv, and Bernhard von Hagen.  This was the first classification of gentians since Ernst Gilg’s system from 1895. It was also the first comprehensive treatment of the family since Grisebach’s (1839) gentian monograph, which was published in Latin.

    The most recent worldwide family treatment will be published soon as part of the global Families and Genera of Vascular Plant series (in press)

Publications: Struwe & Pringle, in press; Struwe & Albert, 2002; Struwe et al., 2002

Neotropical biogeography: geology, speciation and geography in Latin America

Neotropical biogeography is one of my main interests, focusing primarily on the tepuis and the lowland white-sand savannas (on nutrient-poor and ancient sediments, with vegetation known as Amazon caatinga) in the Amazon basin. The tepuis are flat-topped and sharp-cliffed mountains of the Guayana Highlands in eastern Venezuela, northern Brazil, and Guyana.  I am working on research questions such as: Are the montane species of the tepui summits derived from ancestral lineages present in lowland rainforests and white-sand savannas or from montane areas such as the Andes?  Are species endemic to the nutrient poor and ancient lowland white-sand areas in the Amazonas the oldest, relictual remnants of isolated evolutionary branches of the gentian family tree?  What are the biogeographic relationships between plants in the Andes, the Amazon Basin, the Caribbean, and the two ancient geological Shields in South America (the Brazilian Shield in the southeast and the Guayana Shield in the north)? The tribe Helieae and the genus Potalia are used as model organisms for these biogeographic studies.

Publications: Mansion & Struwe, 2004; Struwe, 1999, in press; Struwe & Albert, 2002; Struwe et al., 2002, 2006

Evolution in tribe Helieae (Gentianaceae)

The gentian tribe Helieae occur only in Latin America and include Calolisianthus, Chelonanthus, Irlbachia, Macrocarpaea, Symbolanthus, and Tachia, etc. This monophyletic group of ca. 200 species contains both woody and herbaceous species and displays large variation in habit, leaves, flowers, and fruits.  Many species are narrow endemics and restricted to small areas or habitats such as tepui summits and their associated slopes with rainforest, or white-sand savannas, Andean mountain ridges, islands in the Caribbean, or highland savannas or forests in southeastern Brazil.  Molecular data from the ITS and 5S-NTS DNA regions is used to resolve phylogenetic relationships within this group and to analyze biogeographical patterns.  In the Helieae many different pollinators can be found, from hummingbirds in Symbolanthus and Lagenanthus, bats in some Chelonanthus and Macrocarpaea, insects in several genera, and hawkmoth pollination in Aripuana and Macrocarpaea.  I aim at investigating the evolution of floral traits and pollination syndromes, and also characters such as secondary woodiness, hairy leaves, inflorescence position, and pollen aggregation into tetrads and polyads in this group of gentians.  The traditionally difficult generic delimitations and species relationships in the group are being resolved using cladistic methods and modern molecular techniques.

Publications: Gould & Struwe, 2004; Grant & Struwe, 2001, 2003; Grant et al., 2006; Struwe, 2003; Struwe & Albert, 1998, 2002; Struwe & Gould, 2004; Struwe et al., 1999, 2002, 2005

Saccifolium (Gentianaceae; formerly Saccifoliaceae)

The phylogenetic position of Saccifolium bandeirae from the mountain Sierra de la Neblina on the Brazilian-Venezuelan border, had been uncertain since its discovery decades ago when it was described as the sole member of the family Saccifoliaceae.  Saccifolium has now been shown to be a member of the most basal clade of the Gentianaceae, the new tribe Saccifolieae, together with e.g., Curtia and the saprophytic genus Voyriella.

Publications: Struwe & Albert, 2002; Struwe et al., 2002; Thiv et al., 1999

Evolution in Potalieae (Anthocleista, Fagraea, and Potalia; Gentianaceae)

The tribe Potalieae was also excluded from Loganiaceae and is now placed in the Gentianaceae, a strongly supported position based on molecular, morphological, anatomical, and phytochemical data.  Phylogenetic and biogeographic relationships between and within Potalia, African-Malagasy Anthocleista, and Asian-Australian-Pacific Fagraea (all in the Potalieae) are being investigated using morphological and molecular data. Potalia and its closely related genera Anthocleista and Fagraea of Potalieae are tropical woody genera with showy flowers and fleshy or leathery berries, whereas most gentians are smaller herbs or shrubs with dry capsular fruits.  Potalia is restricted to the Neotropics and seven species are now recognized - as compared to only one species previously.  Potalia is also the gentian that is most used pharmacologically by people in the New World.  It is used against snake bites and other animal bites, poisonings, stomach aches, inflammations, fungal infections, fevers, and many other health problems.

Publications: Struwe & Albert, 1997, 2002, 2004; Struwe et al., 1998, 2002

Flower development in gentians

Other areas of my research are floral and fruit development in Gentianaceae. I investigate postgenital fusion of ovaries, development of berries vs. capsules, and anatomy and vascularization of flowers in the tribe Helieae and Potalieae. Another research project is early flower development of the supermerous flowers of Potalia and Anthocleista of tribe Potalieae.  Their unique flowers have 8-16 corolla and stamen parts instead of the usual 4 or 5 lobes/stamens characteristic for most other gentians.

Publications: Struwe, 1999; Struwe & Albert, 2002; Struwe et al., 1997, 2002

Evolution in Loganiaceae

I have also been working on the systematics of the tropical and subtropical family Loganiaceae in its older, traditional and larger circumscription.  Nowadays, several former Loganiaceae genera are placed in other families, for example: the butterfly bush (Buddleja) in Buddlejaceae (order Lamiales), Desfontainia in Desfontainiaceae, yellow jessamine (Gelsemium) in Gelsemiaceae (Gentianales), Sanango and Peltanthera in Gesneriaceae (Lamiales), and Retzia in Stilbaceae (Lamiales). Left in Loganiaceae proper are only 13 genera, namely Antonia, Bonyunia, Gardneria, Geniostoma, Labordia, Logania, Mitrasacme, Mitreola, Neuburgia, Norrisia, Spigelia, Strychnos, and Usteria. Graduate student Cynthia Frasier participates in this project.

Publications: Albert & Struwe, 2002; Molina & Struwe, 2004; Struwe & Albert, 1997; Struwe & Motley, in press; Struwe et al., 1994.

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