Tag Archives: Taxonomy

Mnemonics are an Effective Tool for Adult Beginners Learning Plant Identification

Mnemonics are an Effective Tool The decline in interest in plants in biological education is an established phenomenon. Compared to animals, plants are under-represented in biology textbooks and other media. Biology teachers often avoid using plant examples in class due to their own lack of knowledge or interest, perpetuating the cycle. With botanical topics often relegated to single modules or lecture sets and limited opportunities for fieldwork, learning of species identification has inevitably suffered.

Species identification is a fundamental requirement for learning and understanding biodiversity, but it also plays a role in fostering concern for its preservation. Plant identification draws people’s attention to the wide variation in plant form, texture, colour, etc., increasing their interest in plants and their appreciation of biodiversity. Given the rapid rate of decline of plant species and consequences for wider ecosystems, there may be a greater need than ever to find ways to promote identification skills not only in the classroom but among the general public.

Most beginners are introduced to plant diversity through identification keys, which develop differentiation skills but not species memorisation. A paper in the Journal of Biological Education proposes that mnemonics, memorable ‘name clues’ linking a species name with morphological characters, are a complementary learning tool for promoting species memorisation.

In the first of two experiments, 64 adults in a group-learning environment were taught species identification using mnemonics, an educational card game and a text-based dichotomous key. In the second experiment, 43 adults in a self-directed learning environment were taught species identification using mnemonics and a pictorial dichotomous key. In both experiments, mnemonics produced the highest retention rates of species identification based on vegetative characters. The educational value of these findings is discussed for vegetative plant identification and broader applications. Participants in this study also enjoyed mnemonics more than a keying-out activity, suggesting that they could help to stimulate interest in botany.

Bethan C. Stagg and Maria E. Donkina. Mnemonics are an Effective Tool for Adult Beginners Learning Plant Identification. Journal of Biological Education 27 Feb 2015 doi: 10.1080/00219266.2014.1000360

Phylogeny and biogeography of wild roses

Phylogeny and biogeography of wild roses The genus Rosa (with 150–200 species) is widely distributed throughout temperate and sub-tropical habitats from the northern hemisphere to tropical Asia, with only one tropical African species. In order to better understand the evolution of roses, this study examines infrageneric relationships with respect to conventional taxonomy, considers the extent of allopolyploidization and infers macroevolutionary processes that have led to the current distribution of the genus.

The ancestral area reconstruction suggests that despite an early presence on the American continent, most extant American species are the results of a later re-colonization from Asia, probably through the Bering Land Bridge. The results suggest more recent exchanges between Asia and western North America than with eastern North America. The current distribution of roses from the Synstylae lineage in Europe is probably the result of a migration from Asia approx. 30 million years ago, after the closure of the Turgai strait. Directions for a new sectional classification of the genus Rosa are proposed, and the analyses provide an evolutionary framework for future studies on this notoriously difficult genus.

Fougère-Danezan, M., Joly, S., Bruneau, A., Gao, X. F., & Zhang, L. B. (2014) Phylogeny and biogeography of wild roses with specific attention to polyploids. Annals of Botany, December 29, 2014, doi: 10.1093/aob/mcu245

Hitting the right target: taxonomic challenges for, and of, plant invasions

Primroses (genus Oenothera) are one of the group where it is difficult to align taxa invasive in Europe to their native North American counterparts.

Primroses (genus Oenothera) are one of the group where it is difficult to align taxa invasive in Europe to their native North American counterparts.

Taxonomic resources are essential for the effective management of invasive plants because biosecurity strategies, legislation dealing with invasive species, quarantine, weed surveillance and monitoring all depend on accurate and rapid identification of non-native taxa, and incorrect identifications can impede ecological studies. On the other hand, biological invasions have provided important tests of basic theories about species concepts. Modern taxonomy therefore needs to integrate both classical and new concepts and approaches to improve the accuracy of species identification and further refine taxonomic classification at the level of populations and genotypes in the field and laboratory. In a recent review in AoB PLANTS, Pysek et al. explore how a lack of taxonomic expertise, and by implication a dearth of taxonomic products such as identification tools, has hindered progress in understanding and managing biological invasions. They also explore how the taxonomic endeavour could benefit from studies of invasive species.

Reasons to be cheerful (Parts, 4…)

Image: Wikimedia Commons.

Image: Wikimedia Commons.

Backward-looking retrospectives [is there any other kind? – Ed.] are great. And that from the International Institute for Species Exploration at Arizona State University is one of the best. Annually, it publishes its list of the Top 10 new species discovered in the preceding year. Whilst this column has previously bemoaned the paucity of plant-based entrants in prior year’s lists, it is pleased to share news that there are four botanical worthies in the 2012 listing. And the list’s pedigree is unimpeachable because the committee members – who pick the ten – were ‘free to use any criteria they wished, keeping in mind the purpose of the Top 10 is to draw attention to biodiversity and the science and institutions engaged in its exploration. They were also encouraged to pay attention to taxonomic, geographic, and natural history diversity’. Their Top 10 includes Viola lilliputana, known from a single locality in the dry puna grassland ecoregion in the Peruvian Andes. At barely 1 cm (10 000 µm!) tall, the Lilliputian violet is a tiny miracle of nature and hard to spot, which may help to protect it from the over-zealous attentions of ‘collectors’ and agriculturalists who have all but extirpated the African violet from the wild. Also in the list is Eugenia petrikensis from Madagascar, whose uniqueness is ‘its rare occurrence, a large shrub with its beautiful bunch of flowers hanging on its branchlets’. However, I think it’s there because its leaf venation is brochidodromous*. Also in the list is Ochroconis lascauxensis which was isolated from ‘black stains’ in the Lascaux Caves in south-western France. Yes, I know it’s not a plant – it’s a fungus – but since fungi are non-animals, that’s good enough for this column (and, anyway, fungi are covered by the same ‘taxonomic code’ as plants; so, Botanists: 3, Others: 0, I think!). Finally – and I know all true botanists will appreciate this – also claimed for us chlorophytes is Juracimbrophlebia ginkgofolia, a new fossil species – a ‘hanging-fly’ – from Middle Jurassic deposits in the Jiulongshan Formation (in China’s Inner Mongolia). Yes, I know it’s an insect, but it was found with preserved leaves of a ginkgo-like tree, Yimaia capituliformis (presumably not Y. juracimbrophlebia-similiformis since I expect the plant was named first…), which it looks remarkably similar to (hence its specific epithet…)! What, an insect that wants to be a plant? How cool is that! And therefore thoroughly deserving of the honorary plant status I’m happy to accord it. What of the other organisms in the 2012 Top 10? Just some animals – sorry. However, what about a ‘spective’? A look-forward, where we second-guess the weirdest organisms we can imagine being discovered in 2013 (or beyond). What sort of plants would you propose? But if a single year’s list is too tame for you, you might like to know that the RHS’s (the UK’s Royal Horticultural Society) Plant of the Centenary is Geranium Rozanne (‘Gerwat’).

[* This sounds much more impressive than it is; brochidodromous venation means that ‘with a single primary vein, the secondary veins not terminating at the margin but joined together in a series of prominent upward arches or marginal loops on each side of the primary vein’, i.e. second-order veins are joined (there’s a good diagram thereof in Fig. 2A of Anita Roth-Nebelsick et al.’s 2001 review of the evolution and function of leaf venation architecture). And, yes, I know Saintpaulia isn’t a true violet, but it’s ‘literary licence’; so, no letters telling Mr P. Cuttings off, please! – Ed.]

Australia’s national flower is an invasive species – even in Australia

Phylogeography of invasive Acacia

Phylogeography of invasive Acacia

Australia’s national flower, Acacia pycnantha (the golden wattle), is native to New South Wales, Victoria and South Australia. And very pretty it is too. But this species was introduced and has become invasive in Western Australia and is probably naturalizing in some areas of New South Wales and South Australia from cultivated plantings in revegetation projects and along roadsides. A. pycnantha is also an invasive species in the Eastern and Western Cape Provinces of South Africa, in Portugal, and possibly in California.

Understanding botanical introduction and invasion histories has important practical implications. The selection of effective host-specific biocontrol agents for invasive plants can depend on identifying which subspecific entities of the plant were introduced. Following the success of other biological control agents against Australian acacias in South Africa, a gall-forming wasp and a seed-feeding weevil have been used to try to control the plant.

A recent paper published in Annals of Botany aims to place invasive populations of Acacia pycnantha in the context of historical biogeographical patterns in the native range of the species in south-eastern Australia. The authors use plastid and nuclear DNA markers to reconstruct phylogenetic relationships among invasive and native populations, and to compare genetic diversities in these invasive and native populations. They show that the invasive genotype found in South Africa is similar to the invasive genotypes in Portugal and Western Australia and thus introduction of the same variant of gall-forming wasp successfully used for biological control in South Africa is recommended.

 

Elucidating the native sources of an invasive tree species, Acacia pycnantha, reveals unexpected native range diversity and structure. (2013) Annals of Botany 111 (5): 895-904. doi: 10.1093/aob/mct057
Understanding the introduction history of invasive plant species is important for their management and identifying effective host-specific biological control agents. However, uncertain taxonomy, intra- and interspecific hybridization, and cryptic speciation may obscure introduction histories, making it difficult to identify native regions to explore for host-specific agents. The overall aim of this study was to identify the native source populations of Acacia pycnantha, a tree native to south-eastern Australia and invasive in South Africa, Western Australia and Portugal. Using a phylogeographical approach also allowed an exploration of the historical processes that have shaped the genetic structure of A. pycnantha in its native range. Nuclear (nDNA) and plastid DNA sequence data were used in network and tree-building analyses to reconstruct phylogeographical relationships between native and invasive A. pycnantha populations. In addition, mismatch distributions, relative rates and Bayesian analyses were used to infer recent demographic processes and timing of events in Australia that led to population structure and diversification. The plastid network indicated that Australian populations of A. pycnantha are geographically structured into two informally recognized lineages, the wetland and dryland forms, whereas the nuclear phylogeny showed little geographical structure between these two forms. Moreover, the dryland form of A. pycnantha showed close genetic similarity to the wetland form based on nDNA sequence data. Hybrid zones may explain these findings, supported here by incongruent phylogenetic placement of some of these taxa between nuclear and plastid genealogies.
It is hypothesized that habitat fragmentation due to cycles of aridity inter-dispersed with periods of abundant rainfall during the Pleistocene (approx. 100 kya) probably gave rise to native dryland and wetland forms of A. pycnantha. Although the different lineages were confined to different ecological regions, we also found evidence for intraspecific hybridization in Victoria. The invasive populations in Portugal and South Africa represent wetland forms, whereas some South African populations resemble the Victorian dryland form. The success of the biological control programme for A. pycnantha in South Africa may therefore be attributed to the fact that the gall-forming wasp Trichilogaster signiventris was sourced from South Australian populations, which closely match most of the invasive populations in South Africa.

 

Plastid and nuclear variation among apomictic polyploids

Plastid and nuclear variation among apomictic polyploids`

Plastid and nuclear variation among apomictic polyploids

Apomicts (plants grown from seeds or spores are produced without fertilization) account for 20–50 % of all species in northern Europe, but both phylogeny and evolutionary processes in apomictic genera remain largely unknown. Tyler and Jönsson use chloroplast sequences and nuclear microsatellites to create an overview of the variation in one of the most species-rich of all plant genera, Hieracium sensu stricto (hawkweed; Asteraceae). Although they find that cpDNA show too little variation and microsatellites are too variable to resolve relationships among species or evolutionary processes, they conclude that both species and sections as defined by morphology are congruent with the molecular data, that gene flow between the sections is rare, and that the tetraploid species may constitute the key to understanding evolution and speciation in Hieracium.

Chlorophyllous catwalk… (Or, Hemerocallis, the ‘lily’ whose day has come?)

Image: José Goulão/Wikimedia Commons.

Image: José Goulão/Wikimedia Commons.

Question: what have Arabidopsis thaliana, Lotus japonicus, Zea mays, Lemna gibba and Hemerocallis got in common? Answer: they’re all model plantsnon-human species that are extensively studied to understand particular biological phenomena, with the expectation that discoveries made in the organism model will provide insight into the workings of other organisms.

OK, maybe not yet in the case of Hemerocallis, but a very strong – and overwhelmingly compelling? – case for its elevation to that exalted status has been made by María Rodríguez-Enríquez and Robert Grant-Downton. Maybe somewhat presciently, Hemerocallis (the daylily) is apparently often called ‘the perfect perennial’. And there are many good reasons why H. should be accorded model organism status. The two particularly highlighted by the paper’s authors are the strict developmental control of flower opening and flower senescence (programmed cell death, PCD), and its self-incompatibility (SI) system (SI is a general name for several genetic mechanisms in angiosperms that prevent self-fertilization and thus encourage outcrossing). In the words of its most fervent supporters, ‘New insights into fascinating subjects such as PCD, SI systems and the cellular, molecular and genetic basis of morphological innovations could be generated by exploration in this genus.

Equally, more applied studies, such as identifying and studying molecules of potential biomedical importance, would be assisted by embracing Hemerocallis as a model organism. Its impact as a future model will be enhanced by its amenability to cultivation in laboratory and field conditions… In addition, established methods for various tissue and cell culture systems as well as transformation will permit maximum exploitation of this genus by science… We look forward to a future where many more plant biologists are not only aware of, but also actively utilizing, Hemerocallis in research’.

Having reviewed the ‘manifesto’, as far as I can see the only thing against Hemerocallis’ formal adoption as a model plant (is there a committee that rules on such weighty matters? Should there be…?) – apart from the fact that the genus is in the really-hard-to-spell family Xanthorrhoeaceae (well, probably, for now – it seems that its family status is a little labile at present…) – is that it’s not arabidopsis. But neither is Lotus japonicus, nor Zea mays, nor Lemna gibba… And – but not that looks should count for anything – it will certainly look prettier in the lab than arabidopsis (and it is ‘full-size’, not scale-model size)! So, and anyway, Hemerocallis gets my vote!

[If there are deemed to be too many model plants, perhaps organisms should be in place for a 5-year term, and then have to be put up for re-election. How that might change the grant-awarding landscape! – Ed.]

Plight of Plant taxonomy and taxonomists in India: What, Why and How?

An entry by R. Siva and S. Babu of VIT University.

The identifiable Aeschynanthus radicans

If you can’t identify Aeschynanthus radicans how can you do science? Photo: Jacinta Lluch Valero/Flickr

Plant Systematics involves the recognition, comparison, classification and naming the millions of plants that have existed and exist at present on the earth. India is rich in plant diversity and possesses almost 7% of the world’s flowering plants.1 In addition, India has a relatively good number of bryophytes (approximately 3000) and pteridophytes (approximately 1400). Most of the plants reported in India are based on the work of British taxonomists like Hooker or Gamble. The fact is that India lacks expertise in the field and there is a scarcity of knowledgeable taxonomists in India. At present, there could be only few ‘finger-countable’ plant taxonomists in India, the country where vast reserves of flora are yet to be studied. Many legendary plant taxonomists are either no more or retired with no replacement. The sporadic and limited studies on taxonomy in India are mainly oriented towards angiosperms. Cryptogams are long neglected from both taxonomical documentation and research exploitation

This subject has failed to attract the young researchers. One reason could be the educational system in India. Different branches of science are perceived not to have equal value. For instance, only few universities offer botany or zoology courses for graduate studies. If this situation persists, at some point in time, botany and zoology will have to be categorized as `endangered subjects’.2

There have been several earlier publications emphasizing on the fate of taxonomy and taxonomists in India3-5 as well as other parts of the world.6-7 Despite there has not been much change in the overall scenario. This has undoubtedly left a great deal of vacuum in this important field of taxonomy.

We propose the following as initial ways to change the present scenario in this aspect.

  1. Proper recognition of plant taxonomists in the form of awards and rewards.
  2. Specialized institutes on plant taxonomy in addition to Botanical Survey of India so as to make enough room for job opportunities.
  3. Introduction of plant taxonomy in the existing syllabi of undergraduate biology and biotechnology courses.
  4. Establishment of more number of research centres in the name of “Institute of Plant Biology”, with plant taxonomy focus.

Acknowledgments:

We sincerely thank Prof. Sean Mayes, Department of Crop Genetics, University of Nottingham and Prof. R. Uma Shaanker, University of Agricultural Science, India for their critical comments

References

  1. Ajmal Ali M. & Choudhary R.K. (2011). India needs more plant taxonomists, Nature, 471 (7336) 37-37. DOI:
  2. Siva, R., 2005. ‘Science becoming `endangered?’’, The Hindu, Education Plus, Oct. 31st.p 8.
  3. Dharmapalan B. (2001). Role of funding agencies for the betterment of taxonomy, Current Science, 81 (6) 629. PDF: http://www.currentscience.ac.in/Downloads/download_pdf.php?titleid=id_081_06_0629_0629_0
  4. Hariharan G.N. & Balaji P. (2002). Taxonomic research in India: Future prospects, Current Science, 83 (9) 1068-1070. PDF: http://www.currentscience.ac.in/Downloads/download_pdf.php?titleid=id_083_09_1068_1070_0
  5. Kholia B.S. & Fraser-Jenkins C.R. (2002). Misidentification makes scientific publications worthless – save our taxonomy and taxonomists, Current Science, 100 (4) 458-461. PDF: http://www.currentscience.ac.in/Volumes/100/04/0458.pdf
  6. Wägele H., Klussmann-Kolb A., Kuhlmann M., Haszprunar G., Lindberg D., Koch A. & Wägele J.W. (2011). The taxonomist – an endangered race. A practical proposal for its survival, Frontiers in Zoology, 8 (1) 25. DOI:
  7. Guerra-García J.M., Espinosa F. & García-Gómez J.C. (2008). Taxonomy today: an overview about the main topics in Taxonomy, Zoologica baetica, 19 15-49. URL: http://www.ugr.es/~zool_bae/vol19/Zoo-2.pdf

Photo: Aeschynanthus radicans by Jacinta Lluch Valero. This image licensed under a Creative Commons by-sa licence.

Botany, a man’s world?

Image: Wikimedia Commons.

Image: Wikimedia Commons.

What do you make of this: ‘In the 18th century, not yet 30 years old, she became the first woman to travel around the world. Along the way she helped collect thousands of plant specimens, some of which were new species. And she did it all dressed as a man’?

Sounds incredible, I know but apparently it is true and relates to one Ms Baret (or Baré). To cut a long (but fascinating!) story short, a wrong – that no plant was named after this indefatigable plants-person – has now been righted by Eric Tepe et al. Their article entitled, ‘A new species of Solanum named for Jeanne Baret, an overlooked contributor to the history of botany’ formally describes Solanum baretiae Tepe, sp. nov. As the authors proudly declare ‘This species in [sic] named in honor of Jeanne Baret (1740–1807), an unwitting explorer who risked life and limb for love of botany and, in doing so, became the first woman to circumnavigate the world… a woman dressed as a man, a female botanist in a male-dominated field, and a working class woman who had travelled farther than most aristocrats’.

Fittingly, S. baretiae is a new member of a cosmopolitanly cultivated, well-travelled and important food genus, suitably befitting for such a cosmopolitan, well-travelled lady! And let us not forget that the genus – Solanum – includes S. tuberosum, the potato, which itself can be dressed up in many different guises, e.g. chips (aka ‘fries’ in the USA, ‘frites’ in France, and – allegedly – ‘Fritz’ in Germany), mashed potato, duchess potato, jacket potato and crisps (bizarrely called ‘chips’ in the USA). But cross-dressing, eh? I think I’d be cross if I had to dress as a woman to pursue my botanical passion; but if that’s what it takes… Hopefully, however, and nowadays, we are much more egalitarian and anybody with the appropriate aptitude can aspire to be a botanist. Though with scientific names like Phallus impudicus and Clitoria for organisms within the remit of the Melbourne Code, and what with that racy Scandinavian Mr Linnaeus’ overtly sexually charged plant classification system, maybe botany is not such a suitable pastime for the gentler sex – or those otherwise of a nervous or sensitive disposition…?