Tod Stuessy

• Ph.D.
• Professor Emeritus at The Ohio State University

The backbone of interpreting patterns of relationship and inferring processes of evolution must be done within the context of phylogeny. Early efforts in phylogenetic reconstruction in Melampodium in the 1970s were based on morphology and cytology. The resolution of evolutionary relationships among all species was greatly improved with nuclear and...

This chapter presents in some detail the range of chromosomal variation within Melampodium. Surveys over several decades have resulted in chromosome numbers being determined for all 40 species, including those described more recently. The range of haploid numbers is broad with n = 9, 10, 11, 12, 14, 18, 20, 23, 24, 27, 28, 30, and 33. Karyotypes ha...

This chapter summarizes the breadth of morphological variability within and among species and indicates which morphological characters are particularly useful taxonomically within the genus. There is a striking range of morphological types ranging from tiny, prostrate herbs to suffruticose shrubs, and erect herbs over two meters tall. Most of the s...

Phylogenies make it possible to infer modes of speciation within Melampodium. This chapter begins with an analysis of isolating mechanisms in the genus, with emphasis on spatial and ecological differentiation. Phenological differences among species are rare. Another mode of isolation derives from the presence of different chromosome numbers that mi...

Human survival depends upon maintaining and preserving biodiversity, which provides fundamental services and products. Learning about biodiversity in all taxonomic groups and all parts of the planet provides us with a deeper understanding to allow management of the global ecosystem for future generations. Monographic studies are an important means...

With such a diversity of chromosome numbers and broad morphological diversity within Melampodium, these data have impacted classification within the genus. Chromosome numbers have been seen as significant at the sectional level going back to the first comprehensive revision. New molecular phylogenetic studies have greatly improved the understanding...

The present concentration of species of Melampodium is in western Mexico, an area of considerable habitat (vegetational) diversity, where the Sierra Madre Occidental, the Sierra Madre del Sur, The Balsas Depression, and the Mexican Transvolcanic Belt converge. Ancestral area reconstruction infers this region as ancestral for the genus. Similarly, r...

Melampodium ranges from Arizona south throughout Mexico and down into Central America and northern South America. One species, M. divaricatum, has become invasive in many other countries, having been reported in Cuba, Brazil, the Philippines, and elsewhere. Most of the interest centers on Mexico, where 39 species occur in many different ecological...

Armed with more robust phylogenetic hypotheses, it has been possible to examine with more precision the evolution of chromosomes within Melampodium. Analyses have revealed that the base number of the genus is x = 11 (the same number observed in the related genera Acanthospermum and Lecocarpus), other base numbers (x = 9, 10, 11, 12, 14) originating...

Within the large family Asteraceae (23,000 species), Melampodium, containing 40 species, belongs to the Heliantheae Alliance, tribe Millerieae. The genus is characterized by radiate heads, 3–5 outer involucral bracts (phyllaries), envelopment of the female, fertile ray achenes by the inner series of morphologically variable phyllaries, and function...

Background The genus Robinsonia DC. (tribe Senecioneae, Asteraceae) endemic to the Juan Fernández Islands in Chile is one of the most conspicuous insular plant groups in the world. Unlike typical herbaceous Asteraceae plants, these plants demonstrate spectacular and unusual rosette tree growth forms as shown by the alpine giant senecios (genus Dend...

Premise Island plants have long interested biologists because of their distinctive morphological features and their isolation on small land areas in vast oceans. Studies of insular endemics may include identifying their ancestors, tracing their dispersal to islands, and describing their evolution on islands, including characters adaptive to island...

Erigeron represents the third largest genus on the Juan Fernández Islands, with six endemic species, five of which occur exclusively on the younger Alejandro Selkirk Island with one species on both islands. While its continental sister species is unknown, Erigeron on the Juan Fernández Islands appears to be monophyletic and most likely evolved from...

The human footprint on marine and terrestrial ecosystems of the planet has been substantial, largely due to the increase in the human population with associated activities and resource utilization. Oceanic islands have been particularly susceptible to such pressures, resulting in high levels of loss of biodiversity and reductions in the numbers and...

Based on molecular phylogenetic studies, Barnadesioideae have been proposed to be the basal subfamily of Asteraceae. This is a complex of 10 genera and 87 species distributed primarily along the Andean mountains, Patagonia, and into southern Brazil and Uruguay. Phylogenetic analyses have recovered all genera as monophyletic groups and have provided...

Based on molecular phylogenetic studies, Barnadesioideae have been proposed to be the basal subfamily of Asteraceae. This is a complex of 10 genera and 87 species distributed primarily along the Andean mountains, Patagonia, and into southern Brazil and Uruguay. Phylogenetic analyses have recovered all genera as monophyletic groups and have provided...

A new endemic species, Centaurodendron schilleri, is described from the Juan Fernández Archipelago, Chile. This is the third species of the endemic genus, Centaurodendron, which is closely related to Plectocephalus of the Chilean mainland. The new species is confined to Alejandro Selkirk Island, whereas the previously known species, C. dracaenoides...

Colonization, levels of speciation and vegetational metamorphosis during ontogeny of oceanic islands over geological time are central evolutionary and biogeographic concerns. A suitable archipelago in which to examine such events is the Juan Fernández (Robinson Crusoe) Archipelago, located at 33° S latitude off the coast of continental Chile and co...

Asteraceae subfamily Barnadesioideae (ten genera, c. 90 species), confined to South America, are sister to the remainder of the family. The relative antiquity of the barnadesioids might lead one to expect that they contain more wood features plesiomorphic for the family, but only one character clearly falls in that category. Pits on imperforate tra...

Loss of genetic diversity reduces the ability of species to evolve and respond to environmental change. Araucaria araucana is an emblematic conifer species from southern South America, with important ethnic value for the Mapuche people (Pehuenche); the Chilean Government has catalogued its conservation status as vulnerable. Climatic fluctuations we...

The lentil (Lens culinaris Medik.) belongs to the legume family (Fabaceae), and it possesses benefits at nutritional, sustainable, and crop rotation system levels. Its occurrence and consumption in Chile originated from imports from Canada, but molecular tools now group Canadian lentils apart from those of the Mediterranean agro-ecological zones in...

Dendroseris D. Don comprises 11 species endemic to the Juan Fernández islands in Chile. They demonstrate spectacular and unusual growth forms of rosette trees with extremely variable morphology and occupy wide ecological ranges on the islands. These unique plants are now highly threatened with extinction with very small population sizes, typically...

We performed an integrated phylogeographical and palaeoclimatic study of an early-diverging member of Asteraceae, Duseniella patagonica, endemic to Argentina. Chloroplast and nuclear markers were sequenced from 106 individuals belonging to 20 populations throughout the species range. We analysed genetic spatial distribution, diversity and structure...

Oceanic islands and archipelagos are natural laboratories for investigating patterns and processes of evolution. Islands change through time, resulting in a dynamic ontogeny over millions of years. The combined forces of tectonic plate subsidence and erosion from waves, wind, and rainwater, bring about substantial geomorphological change over milli...

The classification of the family Compositae (Asteraceae) has been much improved in the last decades by the application of molecular methods culminating in the recompilation published in 2009, Systematics, evolution, and biogeography of Compositae . Additional evidence of relationships has come from the use of high‐throughput sequencing methods. Our...

Between Skottsberg’s second and third expeditions to the Juan Fernández Archipelago, other visitors arrived. World War I caused no direct impact on the islands, because Chile was neutral, but the German cruiser, Dresden, followed by three British warships, had anchored In Cumberland Bay to obtain supplies. Believing that the Dresden was leaving, th...

The Challenger expedition was a major scientific undertaking that lasted from 1872 to 1876, stopping on Robinson Crusoe Island from 13–15 November 1875. The botanist, Henry Moseley, collected 105 different species of plants, and these were given to William Hemsley, Royal Botanic Gardens, Kew, who published results in 1884. Hemsley’s report was the...

The constant harassment of Spanish shipping and coastal communities led Spain in 1750 to build Fort Santa Bárbara in the village of San Juan Bautista on Robinson Crusoe Island. A colony of 100–200 people was established, which accelerated cutting of forests for lumber and firewood. In 1793 Spain and England achieved peace, which opened the islands...

Natural disturbances result in landscape modifications during ontogeny of oceanic islands. As an island subsides and erodes over millions of years, the original size and shape of the island is modified and eventually disappears under the sea. Geomorphological modifications have been hypothesized for the Juan Fernández Archipelago. On Alejandro Selk...

The modern period included the U.S.-Chile botanical expedition of 1965, the 12 expeditions from 1980–2011 led by personnel from Ohio State University, the University of Vienna, and the Universidad de Concepción, Chile, and expeditions led by Philippe Danton and Christophe Perrier from Grenoble, France, from 1997 to the present. These efforts have r...

Mary Graham was a well-educated English traveler who visited Robinson Crusoe Island for two days in 1823, during which time she made plant collections. David Douglas, sponsored by the Horticultural Society of London, visited Robinson Crusoe Island 14–18 December 1824 and made collections, commented on the cultivated plants, and obtained seeds. Carl...

Development of San Juan Bautista on Robinson Crusoe Island led to considerable modification of the vegetation. This has been the center of economic development utilizing forest and marine resources as well as a penal colony during the late 18th and 19th centuries. Domesticated animals, left unconfined in the four major valleys, Valle Colonial, Puer...

In the past two decades, Josef Greimler from Vienna and collaborators from Concepción, Chile, have produced modern vegetation maps of all three islands. The plant associations on Alejandro Selkirk Island are distributed in distinct zones. Near the coast is a grassland of introduced Anthoxanthum and Nassella. On the sides of the quebradas occur fore...

The Swedish botanist, Carl Skottsberg, made three expeditions to the Juan Fernández Archipelago: eight days in 1907–1908; five months in 1916–1917; and three months in 1954–1955 (at age 74). The first trip so fascinated Skottsberg that he planned and successfully executed the second major expedition, from which came most of his scientific contribut...

Some personal recommendations for conservation in the archipelago are offered. Many needs have already been achieved, such as permits for research and collecting activities and better control of domesticated animals. More fencing is needed to keep cattle and sheep restricted to areas that now only contain introduced plants. Focus should be on cutti...

The Juan Fernández archipelago lies in the southeastern Pacific Ocean, west of continental Chile at 33°S latitude. There are three major islands: Robinson Crusoe Island, 667 km from the mainland; Santa Clara Island, 1 km southwest of Robinson Crusoe Island; and Alejandro Selkirk Island, 181 km further west into the Pacific Ocean. Robinson Crusoe Is...

More than one-half (267) of the taxa in the Juan Fernández Archipelago consists of weedy plants from Europe (61%), America (excluding Chile, 22%), Chile (11.4%), Africa (2.9%), Australia/New Zealand (2.3%) and the Pantropics (0.6%). Due to human activities in and around the village of San Juan Bautista, Robinson Crusoe Island and Santa Clara Island...

The Juan Fernández Archipelago has an important political significance for Chile. Its position, combined with that of Easter Island, provides the country a strategic area in the eastern Pacific Ocean. The islands are ecologically significant, having been designated as a Chilean national park in 1935, and as a UNESCO Biosphere Reserve in 1977. Impor...

There never were indigenous peoples in the Juan Fernández Archipelago; prior to its discovery by Europeans in 1574, all changes resulted from natural causes. Documentation of visits by numerous explorers provides an account of human impacts to the islands. The archipelago was well situated as a place to repair ships after the arduous voyage around...

Inventories of the vascular flora of the Juan Fernández Archipelago began with reports by Bertero, Philippi and Hemsley in the nineteenth century and have continued to the present day. The recent totals are 135 endemics, 73 natives, and 267 introduced taxa. Blechnum cycadifolium and Dicksonia berteroana are prominent tree ferns in the vegetation of...

The present vascular flora is in a fragile condition. Estimates of the conservation status of native and endemic species indicate that 4/5 of the flora is regarded as vulnerable to critically endangered. From its origin in 1972, CONAF (Corporación Nacional Forestal) has done a very good job with conservation initiatives, and the Plan de Manejo in 1...

Systematic biology is fundamental for providing organized information about the living world. It clarifies what organisms share our planet, and it also reveals the basic short‐term and long‐term processes that have given rise to this diversity. Human society is rapidly modernizing, largely through increased digital communications tied closely to sa...

This is a compilation that includes the obituary of Dr. Turner, printed in the Austin Statesman, 14 June 2020, plus memories by students, colleagues and friends of Billie, slightly edited (but not censured) by Robert P. Adams, ed., Phytologia, Biology Department, Baylor University, Waco, TX, 76798, USA, robert_adams@baylor.edu, Published on-line ww...

The floras of countries of Latin America offer research opportunities on numerous significant themes, such as: adaptation in diverse habitats, island biogeography, speciation in high mountain ecosystems, evolution in lowland tropical zones, and impact from Pleistocene glaciation. Because these biological perspectives transgress country borders, col...

Morphological features of the heads (capitula) of Asteraceae have been used extensively in classification of the family at different levels of the taxonomic hierarchy. Among the various characters, features of stamens have been employed to determine relationships from specific to tribal levels, including size, shape, colour, cell size and shape of...

The Juan Fernández Archipelago is located in the Pacific Ocean west of Chile at 33° S latitude. Robinson Crusoe Island is 667 km from the continent and approximately four million years old; Alejandro Selkirk Island is an additional 181 km west and only one million years old. The natural impacts of subsidence and erosion have shaped the landscapes o...

This article is a Commentary on Wagner et al. 223: 2039–2053.

The article Factors driving adaptive radiation in plants of oceanic islands: a case study from the Juan Fernández Archipelago, written by Koji Takayama, Daniel J. Crawford, Patricio López‑Sepúlveda, Josef Greimler, Tod F. Stuessy was originally published electronically on the publisher’s internet portal (currently SpringerLink) on 13 March 2018 wit...

ABSTRACT. This revision treats the 41 South American species of Hypochaeris, plus the northwest African H. angustifolia, all now placed in a single monophyletic section Phanoderis. The New World species constitute subsection Phanoderis, and the single African species comprises subsection Africana. The species in South America represent a challenge...

Adaptive radiation is a common evolutionary phenomenon in oceanic islands. From one successful immigrant population, dispersal into different island environments and directional selection can rapidly yield a series of morphologically distinct species, each adapted to its own particular environment. Not all island immigrants, however, follow this ev...

Oceanic islands are vulnerable ecosystems and their flora has been under pressure since the arrival of the first humans. Human activities and both deliberately and inadvertently introduced biota have had and continue to have a severe impact on island endemic plants. The number of alien plants has increased nearly linearly on many islands, perhaps r...

The reconstruction of phylogeny is one of the first steps to understanding patterns and processes of evolution in any group of plants in any part of the world. Without a framework of relationships that show relative affinities of organisms, it is impossible to infer modes of speciation and completely inefficient to attempt to test hypotheses. Long...

To allow an appreciation of the evolutionary data and interpretations presented in this book, we provide in this chapter an outline of the botanical expeditions and collecting that have taken place over the past three centuries. The main objective is to indicate that the floristic inventory of the Juan Fernández Islands is strong. In our own invest...

Every current visitor to the Juan Fernández Islands quickly becomes aware that extensive parts of the landscape are devoid of vegetation. This raises the question of whether these areas are naturally barren or have resulted from more recent human (anthropogenic) influence. In this chapter we attempt to answer this question by surveying natural and...

To understand processes and patterns of evolution in any area of the world requires having a clear context of place and time. Oceanic islands have the great advantage in that they are delimited spatially on all sides by water, and in this way, they are more clearly defined than most continental regions. Nevertheless, to interpret evolutionary event...

One of the very positive achievements over the past half century has been the acceptance in human society of the need to preserve global biodiversity. While arguments may still rage over the need to save a particular species of plant or animal in a particular part of the world, especially in consideration of other human needs such as economic devel...

This chapter presents a list of ferns, gymnosperms, and angiosperms that reside in the Juan Fernández Archipelago. Having an inventory of existing species is fundamental to all other data and concepts presented in this book. At a general level, a list of included species provides the reader with a concept of what the flora entails. This is particul...

To reveal evolutionary relationships and to understand modes of speciation in the flora of any part of the world, having chromosome numbers available is essential (Stebbins 1971; Levin 2002; Stuessy et al. 2014a). Strict genetic and epigenetic forces that control heredity and hence affect evolution are most important to investigate, and these have...

Bringing together results from over 30 years of research on the Juan Fernández Archipelago off the coast of Chile, this book offers comprehensive coverage of the plants of these special islands. Despite its remote setting in the southeastern Pacific Ocean, the Juan Fernández Archipelago is in many ways an ideal place to ask and attempt to answer ba...

Oceanic islands represent excellent places for investigating processes of evolution and development of organismic diversity (Warren et al. 2014). Islands offer special challenges because of their dynamic formation, erosion, and subsidence overlain by colonization, establishment, and survival of new biota over millions of years. Although contiguous...

As an overview, the climate of the Juan Fernández Islands is usually classified as a warm-temperate climate, characterized by equivalent dry and moist seasons (Fuenzalida 1966) or, alternatively, as a Mediterranean-type climate with a strong oceanic influence (Hajek and Espinoza 1987). Novoa and Villaseca (1989) define the climate as a warm-marine...

It is well known that the floras of oceanic archipelagos have been long under pressure from human activities (Caujapé-Castells et al. 2010; Trusty et al. 2011; Gillespie et al. 2012; Moreira-Muñoz et al. 2014). Oceanic islands, with their often mild climates, attractive beaches, and fascinating forms of wildlife, have served as magnets to draw peop...

Speciation is arguably the most fundamental process in plant evolution because it leads to evolutionary lines that represent the basic units of plant classification, the species, and is the means of diversification within lineages (Rieseberg and Brouillet 1994; Coyne and Orr 2004). In addition, the plant diversity for a given area is usually presen...

We analysed pappus characters in 31 of the c. 34 accepted Leontopodium spp. (edelweiss). Micromorphological pappus character states were useful for discriminating between individual species and intrageneric groups. The pappus differs in number, length, breadth, surface structure, colour and the tips of the bristles. Several features characterize si...

Chamaerops humilis L. is 1 of 2 native palms occurring in Europe and the only native palm in the West Mediterranean region. Our aims were: (1) to describe its phylogeographic structure; (2) to infer a biogeographic scenario to explain its present distribution; and (3) to assess changes in its distribution from the last interglacial period. Twenty-t...

Phylogenetic systematics, especially involving molecular data, has had a remarkable impact on systematic biology. Numerous tree-building computer programs exist for the reconstruction of phylogenies, and many packages are available for analysis of population genetic data for estimating genetic divergence within and among populations. These advances...

The review of paraphyly in botanical systematics by Schmidt-Lebuhn brings together a number of useful perspectives for the reader. It fails to offer new ideas, however, and it does not recognize the fallacies of strict cladistic classification, namely accepting only holophyletic groups, and insisting that sister groups have the same rank. The reaso...

Phytomelanin is a hard, brown to black, resistant layer found in the pericarp of cypselae of taxa mostly restricted to eight tribes within the Heliantheae alliance of Compositae (also known as the Phytomelanin Cypsela Clade). Sixty-five species in 8 tribes (34 subtribes) were examined for surface sculpturing of the phytomelanin layer and its system...

The genus Leontopodium (Pers.) R.Br. (Asteraceae, Compositae) is economically important for both pharmaceutical and horticultural purposes. This importance, however, has not led to a good understanding of species coherence and the delimitation of species. One fundamental aspect of a good understanding of a species is how many chromosomes it has and...

Over the past 50 years, many different quantitative approaches have been developed to infer systematic relationships, and these have led to three distinct schools of systematics: phenetics, cladistics, and quantitative evolutionary systematics (= explicit phyletics). Phenetics emphasized quantitative assessment of overall similarity and taught the...

Monographs are fundamental for progress in systematic botany. They are the vehicles for circumscribing and naming taxa, determining distributions and ecology, assessing relationships for formal classification, and interpreting long-term and short-term dimensions of the evolutionary process. Despite their importance, fewer monographs are now being p...

Monographs are fundamental for progress in systematic botany. They are the vehicles for circumscribing and naming taxa, determining distributions and ecology, assessing relationships for formal classification, and interpreting long–term and short–term dimensions of the evolutionary process. Despite their importance, fewer monographs are now being p...

The phylogeny of the genus Nassauvia and closely related genera was reconstructed using sequences from the internal transcribed spacer regions (ITS) of nuclear ribosomal DNA. The genus Triptilion is nested within Nassauvia, making the latter genus paraphyletic. Neither of the two subgenera Nassauvia and Strongyloma is resolved as monophyletic, and...

Despite the broad acceptance of phylogenetic principles in biological classification, a fundamental question still exists on how to classify paraphyletic groups. Much of the controversy appears due to (1) historical shifts in terminology and definitions, (2) neglect of focusing on evolutionary processes for understanding origins of natural taxa, (3...

Rumex bucephalophorus is a very polymorphic species that has been subjected to various taxonomic studies in which diverse infraspecific taxa have been recognised on the basis of diaspore traits. In this study we used molecular markers (ITS and AFLP) to explore this remarkable diversity, to test previous hypotheses of classification, and attempt to...

Flavonoid profiles were determined for 11 species representing five genera of Calyceraceae: Acicarpha, Boöpis, Calycera, Gamocarpha, and Nastanthus. Kaempferol, quercetin, 6-methoxykaempferol, and 6-methoxyquercetin (patuletin) were unequivocally identified. Kaempferol and quercetin occurred as 3-O-mono- and 3-O-diglycosides, whereas the latter two...