2013/04/19 by Michael F. Fay · 1 citation
Agricultural and Biological Sciences · Biochemistry, Genetics and Molecular Biology · #Plant Diversity and Evolution #Plant and animal studies #Plant and Fungal Species Descriptions #Biology #Botany
paper · pdf · doi:10.1111/boj.12052
openalex publication_date 2013/04/19 · openalex created_date 2022/05/12 · openalex updated_date 2026/07/30
Monocots (c. 25% of flowering plants) number some 60000 species, of which > 25000 and > 11000 are orchids (Orchidaceae) and grasses (Poaceae), respectively, the latter group being of huge economic importance as the source of many of the major crops for human and animal food. Other well known groups include sedges, rushes, palms and lilies, but, as discussed at previous Monocots Conferences, the monocots also encompass many taxa which were little known and difficult to place in classifications (e.g. Wilson & Morrison, 2000) until the advent of analyses based on DNA sequence data. To mark the 5th International Conference on Comparative Biology of Monocotyledons (Monocots V) to be held in New York in July, a virtual issue of the journal (http://onlinelibrary.wiley.com/journal/10.1111/(ISSN)1095-8339/homepage/monocotsvirtualissue.htm) has been compiled which includes ten significant papers from the 19th–early 21st centuries relating to monocots to give an impression of how the study of monocots has been represented in the Linnean Society journals and how it has changed over this period. These illustrate the use of different types of data (morphological, anatomical, biochemical and molecular) for clarifying patterns of relationships, dating lineages etc. in monocots. Bentham (1877), focusing on Australian monocots, proposed the division of the monocots into four alliances (Epigynae, Coronariae, Nudiflorae and Glumales) based mostly on floral characters and combining ‘practical convenience with supposed natural affinity’; the resulting classification resembles many other monocot systems in that the families now known to form two large orders (Asparagales and Liliales sensu APG III, 2009) were intermingled. Other classifications included in the virtual issue were proposed by Rolf Dahlgren (1980) and Gertrud Dahlgren (1989). These illustrate attempts to organise the monocots into more meaningful higher level groups, and they were among the first to recognize Asparagales and Liliales as distinct orders in a modern sense, albeit not with the same circumscriptions as in the APG system. Dahlgren (1989) did, however, identify areas that she considered still problematic; e.g. she stated that ‘The family taxonomy in this order [Asparagales] is in great need of revision, and the present tendency to split may lead, by secondary fusion of some of these families, to a balanced taxonomy that agrees with evolutionary concepts’. Morphological and anatomical studies on monocots have been well represented in the journal (Schönenberger & von Balthazar, 2012), and several papers in the virtual issue belong in this area. The earliest focuses on mycoheterotrophs. Parasitic plants can be subdivided into mycoheterotrophs (parasites of fungi, often incorrectly referred to as saprophytes in the literature) and haustorial parasites (parasites of other plants), and both forms are widespread in the angiosperms (e.g. Fay et al., 2010, and references therein). However, although several families of monocots include mycoheterotrophs, no monocots are haustorial parasites. Groom (1895) presented one of the earliest detailed anatomical studies of mycoheterotrophic monocots, focusing on Orchidaceae, and summarized work by others, including that of Joseph Hooker (see Fay, 2011, and references therein for further information on Hooker). Other papers in the virtual issue focusing on morphology and anatomy describe variation in plant parts, e.g. leaves (Arber, 1922; Conover, 1991) and seedlings (Haines & Lye, 1979), or use anatomy to inform patterns of relationships (e.g. subfamily Apostasioideae of Orchidaceae; Stern, Cheadle & Thorsch, 1993). Other recent examples have related to Eriocaulaceae (Echternacht et al., 2001), Marantaceae (Ley & Claßen-Bockhoff, 2012), Xyridaceae (Remizowa et al., 2012), Flagellariaceae and Joinvilleaceae (Sajo & Rudall, 2012) and Orchidaceae (Davies & Stipczyńska, 2012). Before DNA sequence data became applicable to studies of plant systematics, other molecular data were used to some extent. Seed proteins, for example, were used to demonstrate that Hanguanaceae, Flagellariaceae and Joinvilleaceae were distinct from each other and merited family status (Lee, Pin & Yew, 1975), but these types of studies often did not allow the development of hypotheses about how the families were related to each other and to other families. The availability of DNA sequence data marked a major change in understanding of relationships of groups of plants to each other, and other types of molecular data were more or less abandoned as a result of major phylogenetic analyses of DNA sequence data (Chase et al., 1995, 2000), and the papers in the Angiosperm Phylogeny Group series (APG, 1998; APG II, 2003; APG III, 2009) and related papers (e.g. Chase, Reveal & Fay, 2009) demonstrate how these data have allowed an increasingly stable system of classification to be developed. The final paper chosen for the virtual issue is an example of the types of additional analyses that are possible with DNA sequence data. Janssen & Bremer (2004) presented the first attempt to estimate crown and stem node ages for orders and families of monocots, based on sequence data and comprehensive taxon sampling, revealing that considerable monocot diversification took place during the early Cretaceous and most families were present at the Cretaceous–Tertiary boundary. Orchidaceae were shown to be among the oldest families, dating back to the early Cretaceous. They commented on possible error sources and the necessity for methodological improvement in molecular dating, and more recent papers relating to dating of phylogenetic trees have involved some of these improved methods (e.g. Pirie & Doyle, 2012; Pillon, 2012; Buerki et al., 2013). In addition to the virtual issue, volume 172 parts 1 and 3 also focus on monocots. In part 1, Kim et al. (2013) present a phylogenetic analysis of Liliales, Behnke et al. (2013) revise the African representatives of Velloziaceae and Jersáková et al. (2013) investigate genome size evolution in Apostasioideae, the first such study for this least well known subfamily of Orchidaceae. Following previous papers on Cyperaceae (e.g. C3 lineages of Cyperus L., Larridon et al., 2011; phylogenetics of Erioscirpus Palla; Yano et al., 2012), Larridon et al. (2013) propose a phylogenetic framework for revising classification of the C4 members of Cyperus. In part 3, Thi, Kim & Kim (2013) present a molecular phylogenetic analysis of Colchicaceae. Then, following on from earlier cytogenetic studies of monocots (e.g. Pellicer, Fay & Leitch, 2010; Bozek et al., 2012; Kaur, Datson & Murray, 2012; Moraes, Leitch & Leitch, 2012; Tacuatiá et al., 2012), de Assis et al. (2013) investigate cytogenetics in Epidendrum L. Papers on phylogenetics in Liliaceae have appeared in the journal (e.g. Clennett et al., 2012, on Erythronium L.) and the next two papers add to this series, focusing on Tulipa L. The first, by Turktas et al. (2013), is a phylogenetic analysis of Turkish Tulipa, recovering the four subgenera currently recognized, and the second, by Christenhusz et al. (2013), is a phylogenetic analysis of Eurasian Tulipa and includes an annotated checklist of recognized names and synonyms. The next two papers relate to orchids. Vale et al. (2013) investigate the reasons for the rarity of Broughtonia cubensis (Lindl.) Cogn., and Pedersen, Watthana & Srimuang (2013) present an investigation of one of the few rheophytic orchids, Epipactis flava Seidenf. Finally, Bugg et al. (2013) present a study of leaf anatomy in Carex L. (Cyperaceae). I hope that the papers in the virtual issue and the two regular issues in the Botanical Journal of the Linnean Society are of interest to the delegates of Monocots V and that the Conference is a great success.