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\"This user's guide covers the highly threatened cycad family and how it is regulated by the Convention on International Trade in Endangered Species (CITES). The text is written for the non-expert and the guide explores the major groups of cycads in trade, their distribution, conservation status, use and levels of trade as well as the likelihood of illegal trade. Exemptions from CITES regulations are also outlined, together with suggestions to aid enforcement. The guide includes a fully illustrated PowerPoint training presentation and a checklist of cycad species, their distribution and synonymy.\"--Page 4 of cover.

Background This study documents cycad-human relationships in Mexico, Belize, Guatemala, El Salvador, and Honduras over the last 6000 years. The impetus was acute need for a better understanding of previously undocumented uses of cycads in this region, and the need to improve cycad conservation strategies using ethnobotanical data. We hypothesized that cycads are significant dietary items with no long-term neurological effects, are important to religious practice, and contribute to cultural identity and sense of place, but that traditional knowledge and uses are rapidly eroding. Guiding questions focused on nomenclature, food and toxicity, relationships to palms and maize, land management issues, roles in religious ceremony, and medicinal uses, among others, and contributions of these to preservation of cycads. Methods From 2000 to 2017, the authors conducted 411 semi-structured ethnographic interviews, engaged in participant-observation in Mexican and Honduran communities, and carried out archival research and literature surveys. Results We documented 235 terms and associated uses that 28 ethnic groups have for 57 species in 19 languages across 21 Mexican states and 4 Central American nations. Carbohydrate-rich cycads have been both famine foods and staples for at least six millennia across the region and are still consumed in Mexico and Honduras. Certain parts are eaten without removing toxins, while seed and stem starches are detoxified via several complex processes. Leaves are incorporated into syncretic Roman Catholic-Mesoamerican religious ceremonies such as pilgrimages, Easter Week, and Day of the Dead. Cycads are often perceived as ancestors and protectors of maize, revealing a close relationship between both groups. Certain beliefs and practices give cycads prominent roles in conceptions of sense of place and cultural heritage. Conclusions Cycads are still used as foods in many places. Though they do not appear to cause long-term neurological damage, their health effects are not fully understood. They are often important to religion and contribute to cultural identity and sense of place. However, because most traditional knowledge and uses are rapidly eroding, new community-based biocultural conservation efforts are needed. These should incorporate tradition where possible and seek inspiration from existing successful cases in Honduras and Mexico.

The near-threatened cycad Dioon edule (Zamiaceae) is distributed in the Sierra Madre Oriental in Mexico. An important ancestral cultural tradition in the region is seed collecting by indigenous and nonindigenous communities to prepare food up to more than six times a year, without the regulation of the frequency of collection and the number of seeds extracted. In natural conditions, 90% of plants die in the early stages of their life cycle, because of natural and anthropic factors. The objectives of this study were to assess the structure and dynamics of populations where seeds are frequently collected and compare with populations where seed collection does not occur to determine the effect. According to our study of demography, seed collection affects the dynamics and structure of the populations by altering the male:female ratio of plants. This could affect the continuity of the species in the long term, since the number of seeds available for incorporation into the population with the possibility of becoming reproductive adults decreases. It is suggested to design plans that allow the sustainable use of this resource and, in turn, allow the conservation of the traditional knowledge of the Xi'iuy indigenous group. Management of sustainable seed collection could be achieved by rotating collection in stands over a minimum period of 15 years, which is long enough to recover the minimum seed production.

The important cultural role of an ancient, endangered plant Under the Shade of Thipaak is the first book to explore the cultural role of cycads, plants that evolved over 250 million years ago and are now critically endangered, in the ancient and modern Mesoamerican and Caribbean worlds. This volume demonstrates how these ancient plants have figured prominently in regional mythologies, rituals, art, and foodways from the Pleistocene-Holocene transition to the present. Contributors discuss the importance of cycads from a variety of disciplinary perspectives, including biology and population genetics, historical ecology, archaeology, art history, linguistics, and conservation and sustainability. Chapters pay special attention to the enduring conceptual relationships between cycads and maize. This book demonstrates how a close examination of cycad-human relationships can motivate conservation of these threatened plants in ways that engage local communities, as well as promote the significance of ancient and modern practices that unite nature and culture . Contributors : Francisco Barona-Gómez | Emanuel Bojorquez Quintal | Mark A. Bonta | Edder Daniel Bustos-Díaz | Dánae Cabrera-Toledo | Michael Calonje | Michael D. Carrasco | Angélica Cibrián-Jaramillo | Joshua D. Englehardt | Jorge González-Astorga | Naishla M. Gutiérrez-Arroyo | José Saíd Gutiérrez-Ortega | Thomas Hart | Jaime R. Pagán-Jiménez | Francisco Pérez-Zavala | Luis Rojas Abarca | Esteban Sánchez Rodríguez | Dennis William Stevenson | Amber M. VanDerwarker | Luis R. Velázquez Maldonado | Andrew P. Vovides

On 12 February 2015, the South African Police Services confiscated 39 Encephalartos longifolius plants (Thunberg's cycad or Zuurberg cycad) and nine Encephalartos lehmannii (Karoo cycad) plants illegally removed from the wild on a farm adjacent to the Darlingtondam section of Addo Elephant National Park (AENP). The confiscated plants were delivered to AENP on Saturday, 14 February 2015 (Figure 1). 

• Niche conservatism is the tendency of lineages to retain the same niche as their ancestors. It constrains biological groups and prevents ecological divergence. However, theory predicts that niche conservatism can hinder gene flow, strengthen drift and increase local adaptation: does it mean that it also can facilitate speciation? Why does this happen? We aim to answer these questions. • We examined the variation of chloroplast DNA, genome-wide single nucleotide polymorphisms, morphological traits and environmental variables across the Dioon merolae cycad populations. We tested geographical structure, scenarios of demographic history, and niche conservatism between population groups. • Lineage divergence is associated with the presence of a geographical barrier consisting of unsuitable habitats for cycads. There is a clear genetic and morphological distinction between the geographical groups, suggesting allopatric divergence. However, even in contrasting available environmental conditions, groups retain their ancestral niche, supporting niche conservatism. • Niche conservatism is a process that can promote speciation. In D. merolae, lineage divergence occurred because unsuitable habitats represented a barrier against gene flow, incurring populations to experience isolated demographic histories and disparate environmental conditions. This study explains why cycads, despite their ancient lineage origin and biological stasis, have been able to diversify into modern ecosystems worldwide.

Taxonomic data is essential to advance the discovery and description of biodiversity, as well as the study of evolutionary processes. Emerging large-scale datasets and new methods of analysis have provided different approaches to describe biodiversity. Here, we present a review of the taxonomic history in Cycadales including an analysis of historical taxonomic concepts and approaches used for species delimitation. We examine the trends in the publication of new species following taxonomic works in books, journals and horticultural catalogues, monographic projects and floras where species treatments were published. In addition, we review the studies concerning species delimitations using the literature available in scientific journals appearing in the database ISI Web of Knowledge. The approaches used were discussed throughout all research focused on empirical and theoretical considerations in each study. We review the current state of the studies on causal processes that have given rise to the currently recognized diversity. The trend shows that taxonomic work on discovery and description of species has been intensive in the last 40 years culminating in 38.8% of binomials published. As a result, we consider the relevance of the monographs and floras for identification of species for other biological disciplines and the content of these contributions is compared and discussed. A total of six criteria (diagnosability, phenetic, phylogenetic, genotypic cluster, niche specialization and coalescent) were detected from the following three approaches to species delimitation within Cycadales: traditional, integrative taxonomy, and monophyletic. In all cases, the results from these species delimitations not only provided a taxonomic treatment or proposed a new species, but also supposedly clarified the other species involved as a result of the new taxonomic concept of the new species described. Most investigations of species delimitation used the traditional approach or a phenetic criteria. Finally, we discuss evolutionary studies on causal processes involved in cycad diversity. This is considered in the context of species delimitation as hypothesis testing for a successful evaluation of variation in both genetic and morphological understanding.

Premise of research. The genus Zamia L. (Zamiaceae), consisting of 79 species, is the most species-rich and widely distributed cycad genus in the New World and arguably the most morphologically and ecologically diverse genus in the Cycadales. However, a strong phylogenetic framework for this genus is still lacking. Methodology. We used a multilocus sequence data set of 10 independent loci (nine single-copy nuclear genes [SCNGs] and one plastid) and extensive taxon sampling (ca. 90% of species) to infer phylogenetic relationships within Zamia. We implemented a concatenated matrix analysis with maximum parsimony, a partitioned maximum likelihood (ML) analysis, and a time-calibrated Bayesian species tree-estimation approach. Diversification, historical biogeography, and ancestral character state reconstruction analyses were conducted using the species tree topology that was the most morphologically and geographically congruent. Pivotal results. We inferred a robust phylogenetic tree for the genus with a strong geographic delimitation of clades and found that four morphological characters typically used for diagnostic purposes in the genus exhibit a high degree of homoplasy. The stem group of Zamia was estimated to have originated at 68.28 Ma (95% highest posterior density [HPD] 51.0–84.5) and the crown group at 9.54 Ma (95% HPD 9.0–10.62). The majority of species richness in the genus appeared during the Pliocene and Pleistocene, with the highest diversification rates occurring in clades comprising Caribbean and South American species. Biogeographic analysis suggests a Caribbean or Mesoamerican origin for Zamia with subsequent dispersal to the Central American Isthmus and South America, where the genus reaches its maximum species and morphological diversity. Conclusions. The high degree of convergence found in multiple morphological characters has historically confounded efforts to elucidate species relationships using nonphylogenetic methods. This study presents the most species-comprehensive, well-resolved hypothesis of phylogenetic relationships within Zamia and provides a strong phylogenetic framework for further studies.

Premise of research. This study compares the pinnule morphology of three fossil Bowenia species, one Eobowenia (fossil) species, and several Bowenia fossil pinnule fragments with the two extant Bowenia species. Methodology. Pinnule area, stomatal density, and size have been measured on fossil and extant specimens. Measures have been correlated with solar radiation and temperature to ascertain any correlations. Environment and climate variables have been chosen, as they have changed since the Eocene and Lower Cretaceous when the Australian and South American fossils were growing. Pivotal results. Two of the fossil Bowenia species and Eobowenia have significantly smaller pinnules than the living species, and all the fossils have relatively small and sparse stomata compared with the living species. Extant Bowenia pinnule area is positively correlated with daily radiation and temperature. Conclusions. Those fossil species with small pinnules likely lived in relatively dark environments where small pinnules aided the capture of sunflecks and/or facilitated light capture. The smaller and sparser stomata may have limited the potential sites for fungal invasion in the extremely humid growth conditions without hampering overall growth rates in the prevailing very high atmospheric CO2 levels.

Aim: Gymnosperms are often described as a marginal and threatened group, members of which tend to be out-competed by angiosperms and which therefore preferentially persist at higher latitudes and elevations. The aim of our synthesis was to test these statements by investigating the global latitudinal and elevational distribution of gymnosperms, as well as their conservation status, using all extant gymnosperm groups (cycads, gnetophytes, ginkgophytes and conifers). Location: Worldwide. Methods: We developed a database of 1014 species of gymnosperms containing latitudinal and elevational distribution data, as well as their global conservation status, as described in the literature. The 1014 species comprised 305 cycads, 101 gnetophytes, the only living representative of ginkgophytes, and 607 conifers. Generalized additive models, frequency histograms, kernel density estimations and distribution maps based on Takhtajan's floristic regions were used. Results: Although the diversity of gymnosperms decreases at equatorial latitudes, approximately 50% of the extant species occur primarily between the tropics. More than 43% of gymnosperms can occur at very low elevations (≤ 200 m a.s.l.). Gymnosperms, considering all species together as well as their main taxonomic groups separately, do not exhibit a latitudinal diversity gradient as commonly observed for many other taxa. Gymnosperms, and especially conifers, are on average less threatened at higher and equatorial latitudes. Main conclusions: Gymnosperms display an unusual latitudinal diversity gradient, which we suggest cannot fully be accounted for by angiosperm dominance and competitive superiority. We hypothesize that other factors explain their present distribution, such as the development of centres of endemism in several regions and the adaptation of certain taxa to cold and arid climates.