Tagged: Asteraceae



Mum’s the word* in new plant book

Chrysanthemum by Twigs Way 2020. Reaktion Books Ltd. Despite being a declared lover of plants, I didn’t include ‘mums’ – as chrysanthemums are commonly known – amongst the plants that I consider most interesting. It was therefore with some misgivings that I approached Chrysanthemum by Twigs Way (which book is here appraised). However, I’m happy to say that I overcame my prejudices, persevered and read the book – and was pleasantly surprised with what I discovered.** Chrysanthemum is just typical… As is typical for a title in publisher Reaktion Books’s Botanical series, Chrysanthemum is relatively short (214 pages), abundantly illustrated...

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Unravelling the genetic makeup of hybrid meadow knapweed populations in North America

Hybridization is thought to be a primary trigger of plant invasions, due to short term hybrid vigour of early generations or increased evolutionary potential in later generations. Yet despite widespread appreciation of the link between hybridization and invasion, few studies have actually tested whether hybridization during invasion reflects short-term vs. advanced generations of introgression. One of the main reasons for this is that identifying hybrids and differentiating them from their parental species presents formidable challenges. In a recent Editor’s Choice paper published in AoBP, Lachmuth et al. present a multifaceted analysis of the invasive meadow knapweed complex that unravels the...

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Graph of heteromorph and monomorph naturalization

Fruit heteromorphism and naturalization success in Asteraceae

Finding the factors that explain invasion success of species is a major objective in ecology. The combination of extensive data on fruit heteromorphism in Asteraceae and the largest global plant-naturalization database offered the unprecedented possibility to add a missing piece to the naturalization-success puzzle.

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Stenogyne angustifolia drawing

Do non-native pollinators provide services to native plants in Hawaii?

A lot of Hawaii’s plants are in trouble. A new study by Clare Aslan and colleagues says over a third are threatened or endangered. Why are they suffering? The authors decided to look at pollination. Has something gone wrong with pollination so plants aren’t reproducing as they should? To answer the question, they went on a stake-out in the Pōhakuloa Training Area on Hawai‘i Island. The team followed eight native species, half of them endangered, to see what happened with pollination. Their results were the plants were all visited by insects alone. However, they found fewer than 1 in 5...

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Hieracium

Sexuality and apomixis in Hieracium are tightly associated with ploidy

Asexual reproduction via seeds (apomixis) is an important speciation mechanism in angiosperms, but its frequency is largely unknown. Mráz and Zdvořák used flow cytometric seed screening to unravel reproductive pathways in more than 50 Hieracium s.str. taxa (Asteraceae) sampled across Europe. They found that diploid taxa produced their seeds solely after double fertilization, i.e. sexually, whereas polyploid taxa reproduced strictly apomictically. However, very rare sexual reproduction was also recorded in certain polyploids. This is the first evidence of functional sexuality in polyploid members of the genus. While strict apomixis can enhance colonization abilities through increased reproductive assurance, residual sexuality increases...

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Namaqualand in bloom

How do pollinators paint the landscape with colour?

When you look at a patch of flowers, you often see clusters of colour. Even when a single species can have many different colours, you get patches. Why? How does a plant know to grow with this colour and not that colour? The answer is it doesn’t. The colour is set by the genes in its seed, so how do those genes get there? Are pollinators somehow involved in creating these patches of similar colours? This is a problem that Jurene Kemp and colleagues have been investigating. The flowers that the team studied are daisies in Namaqualand, South Africa. Namaqualand...

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Aster amellus

Unmasking cryptic biodiversity in polyploids

Up to one-quarter of flowering plant species may have escaped recognition due to processes such as autopolyploidy-whole genome duplication events where polyploids may be morphologically identical to their diploid progenitors. Mairal et al. combine macroevolutionary, microevolutionary and niche modelling tools to disentangle the origin and demographic history of the polyploid complex of Aster amellus (Asteraceae). They demonstrate that diploid and hexaploid A. amellus may be considered as two independent lineages at the onset of their diversification, with separate niches and different evolutionary histories. The considerable cryptic diversity of polyploid taxa should be thus further evaluated in order to obtain a...

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Cariograms showing inter- and intrapopulation site number variation of interstitial telomeric repeats (ITRs) in Anacyclus clavatus.

Variability of interstitial telomeric-like repeats in Mediterranean weedy species

A telomere is the region of DNA that marks the end of a chromosome. The protect the ends of the chromosome, and stop one chromosome from fusing with another. So finding something that looks like a telomere in the middle of a chromosome would be odd – but it happens. And no one knows exactly why. Although interstitial occurrence of telomeric repeat motifs (ITR) has been reported in the genome of a few organisms, the striking level of polymorphism found by Rosata et al. within a single species has not been described before. Rosata and colleagues investigate whether a comparable...

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The cosmopolitan Compositae (or Sunflowers at large…)

Sunflowers by Stephen Harris 2018. Reaktion Books Ltd. Stephen Harris’ Sunflowers isn’t about sunflowers. OK, correction, it is, but it’s not just about sunflowers. Rather, the book celebrates the sunflower family, the Asteraceae (or what those of a certain botanical background know more affectionately as the Compositae). And, why not? With approx. 32,000* species it’s one of the biggest assemblages of flowering plants on the planet, and is therefore a family worthy of celebration. And celebrate that amazing family is what Harris does in this remarkable book. Sunflowers is one of the growing collection of titles in the publisher’s –...

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Plant species and habitats surveyed in the Sacred Valley

Specialisation and modularity of plant-pollinator networks

Modularity is the tendency of certain species to consistently interact with each other. It is a ubiquitous and important property of ecological networks that can determine the level of specialisation of species within those networks. Watts et al. investigate modularity and specialisation of plant-pollinator communities in the Peruvian Andes, a biodiverse region where no work in this area has hitherto been carried out. They find that species at the centre of the modular structure of the plant–pollinator network tend to be the most abundant, with long phenologies. Additionally, they show that generalist plant species with open-access flowers dominate the plant-pollinator...

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Ranunculus japonicus

Robustness of floral organ numbers

Despite the contribution of phenotypic variation in floral morphologies to speciation, species diversity has been recognized by modal morphologies where variation is averaged out. Here Kitazawa and Fujimoto show a relationship between the species-representative phenotype and phenotypic variation, by analysing quantitatively intraspecific variation of the organ numbers within flowers of Ranunculaceae and the numbers of flowers within the capitula of Asteraceae. The relationship followed a common mathematical function, showing robustness on the species-representative organ numbers.

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