An account of the genus Cistanche (Orobanchaceae) in Iraq and taxonomic considerations in the Middle East.

Species limits in the genus Cistanche are poorly understood, despite the plants' long history of use in traditional herbal medicine and food across their range. Here we present a taxonomic account for the genus Cistanche in Iraq, where several taxa have been reported, most of them doubtfully. Using herbarium specimens, images of living material, and taxonomic literature, we found evidence of only one species occurring with certainty in Iraq: Cistanchetubulosa. We found no evidence for the occurrence of other Cistanche species in Iraq, including a putative new entity reported for the region. Our work highlights inconsistencies in the literature, and underscores the importance of examining multiple stable characters for delimiting species in the genus Cistanche.

Mechanics reveals the role of peristome geometry in prey capture in carnivorous pitcher plants (Nepenthes).

Carnivorous pitcher plants (Nepenthes) are a striking example of a natural pitfall trap. The trap's slippery rim, or peristome, plays a critical role in insect capture via an aquaplaning mechanism that is well documented. While the peristome has received significant research attention, the conspicuous variation in peristome geometry across the genus remains unexplored. We examined the mechanics of prey capture using Nepenthes pitcher plants with divergent peristome geometries. Inspired by living material, we developed a mathematical model that links the peristomes' three-dimensional geometries to the physics of prey capture under the laws of Newtonian mechanics. Linking form and function enables us to test hypotheses related to the function of features such as shape and ornamentation, orientation in a gravitational field, and the presence of "teeth," while analysis of the energetic costs and gains of a given geometry provides a means of inferring potential evolutionary pathways. In a separate modeling approach, we show how prey size may correlate with peristome dimensions for optimal capture. Our modeling framework provides a physical platform to understand how divergence in peristome morphology may have evolved in the genus Nepenthes in response to shifts in prey diversity, availability, and size.

Gigantic floating leaves occupy a large surface area at an economical material cost.

The giant Amazonian waterlily (genus Victoria) produces the largest floating leaves in the plant kingdom. The leaves' notable vasculature has inspired artists, engineers, and architects for centuries. Despite the aesthetic appeal and scale of this botanical enigma, little is known about the mechanics of these extraordinary leaves. For example, how do these leaves achieve gigantic proportions? We show that the geometric form of the leaf is structurally more efficient than those of other smaller species of waterlily. In particular, the spatially varying thickness and regular branching of the primary veins ensures the structural integrity necessary for extensive coverage of the water surface, enabling optimal light capture despite a relatively low leaf biomass. Leaf gigantism in waterlilies may have been driven by selection pressures favoring a large surface area at an economical material cost, for outcompeting other plants in fast-drying ephemeral pools.

Thismia sitimeriamiae (Thismiaceae), an extraordinary new species from Terengganu, Peninsular Malaysia.

We describe an extraordinary new species in the genus Thismia from the Terengganu State of Malaysia in the Malay Peninsula. The new species, which we name Thismia sitimeriamiae, is distinct from all other Thismia species known to science, most notably in its unique mitre configuration formed by the inner tepals and its floral surface morphology characterised by conspicuous orange trichomes. We discuss our findings in the context of underestimated species diversity in the genus Thismia and implications for their conservation. We recommend assigning T. sitimeriamiae the conservation status as Critically Endangered (CR) according to IUCN criteria.

Endoparasitic plants and fungi show evolutionary convergence across phylogenetic divisions.

Endoparasitic plants are the most reduced flowering plants, spending most of their lives as a network of filaments within the tissues of their hosts. Despite their extraordinary life form, we know little about their biology. Research into a few species has revealed unexpected insights, such as the total loss of plastome, the reduction of the vegetative phase to a proembryonic stage, and elevated information exchange between host and parasite. To consolidate our understanding, we review life history, anatomy, and molecular genetics across the four independent lineages of endoparasitic plants. We highlight convergence across these clades and a striking trans-kingdom convergence in life history among endoparasitic plants and disparate lineages of fungi at the molecular and physiological levels. We hypothesize that parasitism of woody plants preselected for the endoparasitic life history, providing parasites a stable host environment and the necessary hydraulics to enable floral gigantism and/or high reproductive output. Finally, we propose a broader view of endoparasitic plants that connects research across disciplines, for example, pollen-pistil and graft incompatibility interactions and plant associations with various fungi. We shine a light on endoparasitic plants and their hosts as under-explored ecological microcosms ripe for identifying unexpected biological processes, interactions and evolutionary convergence.

Astonishing Plants.

Our existence depends on plants, yet to many they are invisible, a phenomenon called 'plant blindness'. Addressing this is crucial in the face of unprecedented biodiversity loss and extinction. Digital engagement with astonishing plants can break the perception that they are uninteresting and take us steps forward in addressing disengagement.

Guided droplet transport on synthetic slippery surfaces inspired by a pitcher plant.

We show how anisotropic, grooved features facilitate the trapping and directed transport of droplets on lubricated, liquid-shedding surfaces. Capillary action pins droplets to topographic surface features, enabling transport along the feature while inhibiting motion across (or detachment from) the feature. We demonstrate the robustness of this capillary-based mechanism for directed droplet transport on slippery surfaces by combining experiments on synthetic, lubricant-infused surfaces with observations on the natural trapping surface of a carnivorous pitcher plant. Controlling liquid navigation on synthetic surfaces promises to unlock significant potential in droplet-based technologies. Our observations also offer novel insight into the evolution of the Nepenthes pitcher plant, indicating that the 'pitfall' trapping mechanism is enhanced by the lubricant-infused, macroscopic grooves on the slippery peristome surface, which guide prey into the trap in a way that is more tightly controlled than previously considered.

Convergent and divergent evolution in carnivorous pitcher plant traps.

Contents Summary 1035 I. Introduction 1035 II. Evolution of the pitcher 1036 III. Convergent evolution 1036 IV. Divergent evolution 1038 V. Adaptive radiation and speciation 1040 VI. Conclusions and perspectives 1040 Acknowledgements 1040 References 1040 SUMMARY: The pitcher trap is a striking example of convergent evolution across unrelated carnivorous plant lineages. Convergent traits that have evolved across pitcher plant lineages are essential for trap function, suggesting that key selective pressures are in action. Recent studies have also revealed patterns of divergent evolution in functional pitcher morphology within genera. Adaptations to differences in local prey assemblages may drive such divergence and, ultimately, speciation. Here, we review recent research on convergent and divergent evolution in pitcher plant traps, with a focus on the genus Nepenthes, which we propose as a new model for research into adaptive radiation and speciation.

Specific developmental pathways underlie host specificity in the parasitic plant Orobanche.

Parasitic angiosperms are an ecologically and economically important group of plants. However our understanding of the basis for host specificity in these plants is embryonic. Recently we investigated host specificity in the parasitic angiosperm Orobanche minor, and demonstrated that this host generalist parasite comprises genetically defined races that are physiologically adapted to specific hosts. Populations occurring naturally on red clover (Trifolium pratense) and sea carrot (Daucus carota subsp. gummifer) respectively, showed distinct patterns of host specificity at various developmental stages, and a higher fitness on their natural hosts, suggesting these races are locally adapted. Here we discuss the implications of our findings from a broader perspective. We suggest that differences in signal responsiveness and perception by the parasite, as well as qualitative differences in signal production by the host, may elicit host specificity in this parasitic plant. Together with our earlier demonstration that these O. minor races are genetically distinct based on molecular markers, our recent data provide a snapshot of speciation in action, driven by host specificity. Indeed, host specificity may be an underestimated catalyst for speciation in parasitic plants generally. We propose that identifying host specific races using physiological techniques will complement conventional molecular marker-based approaches to provide a framework for delineating evolutionary relationships among cryptic host-specific parasitic plants.