Tagged: Poaceae




Recent range expansion in Australian hummock grasses

Large-scale environmental changes such as aridification have shaped and continue to influence the evolution and composition of biomes. As conditions change, organisms may persist in some parts of their ranges, become extinct in others, or may migrate into newly available or previously inaccessible ecologically favourable regions. Much of Australia is covered by an arid zone that has developed over the last 15 million years. The Australian arid zone (AAZ) provides an excellent location for exploring the influence of continent-scale aridification on biome assembly. The unique flora that inhabits the AAZ includes plants that have responded differently to climate and landscape...

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Scanning electron microscopy (SEM) images of the upper floret of Chasechloa madagascariensis (Vorontsova et al. 1822).

Museomics reveal phylogeny of endangered Malagasy grasses

Poaceae is one of the most diverse families in Madagascar, but some lineages have not yet been assessed within a phylogenetic framework. This study focused on the threatened taxa of Chasechloa, historically associated with the South American forest grasses of the genus Echinolaena. Silva et al. investigate the evolutionary relationships and origin of Chasechloa using molecular data produced by next-generation sequencing from museum specimens. Chasechloa was found to be only distantly related to Echinolaena. Miocene diversification of Chasechloa is temporally congruent with the origin of other angiosperms in dry forests of North Western Madagascar. Ants may have played a role...

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Past climate change velocity, expected future velocity and the ratio of expected future:past

Stable climate characterises hotspots of grass endemism

Glacial-interglacial climate cycles have far-reaching consequences for ecosystems and it is widely recognised that regions with a history of unstable climates have few endemic species and are susceptible to the establishment of exotic, non-native species from comparatively stable regions. Sandel et al. tested these hypotheses with a global dataset of grass species distributions. Grass endemism is shown to be highly concentrated in regions with historically stable climates. Exotic species occur in areas with extremely stable or unstable climates, with the majority originating from stable regions. This study provides a historical context for the hypothesis that future climate change may increase...

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Nassella pulchra

Summer dormancy and seasonal growth in California perennial grasses

Superior drought survival is expected to result in reduced productivity and competitive ability, but this expectation has seldom been tested in herbaceous perennial species. Balachowski et al. quantified seasonal growth, functional traits, and drought survival strategies in eight California perennial grasses. Contrary to common assumptions, they found that summer dormancy, an adaptation to Mediterranean-type climates, was associated with greater springtime productivity and more competitive functional traits. The authors conclude that, because summer dormancy confers greater functional similarity to exotic annual species currently invading California grasslands, native summer dormant taxa may play an increasingly important ecological role in the future of...

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Polyploidy and long-distance dispersal

Polyploidy and long-distance dispersal

Most of the numerous and remarkable range disjunctions across the southern oceans are probably the result of occasional long-distance dispersal, rather than of vicariance. Linder and Barker study the grass subfamily Danthonioideae, which probably reached its current global distribution by a number of long-distance dispersal events during the Neogene, and show that such dispersal is much more likely in polyploid than in diploid species. It is possible that polyploidy facilitates post-dispersal establishment, and it is postulated that the frequent occurrence of polyploidy in the grasses may thus have facilitated their long-distance dispersal, and hence contributed to the remarkable success of...

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Image: Wikimedia Commons.

M people and the ‘B’ word…

No, this is not an item about M People, an ‘English house music band which formed in 1990 and achieved success throughout most of the 1990s’, nor about using profane language… Anyway, how would any of that be relevant to a straitlaced, sober, serious botanical news round-up that is the hallmark of a P. Cuttings item? It is about the phenomenon (I don’t think that’s too strong a word) known as ‘Dr M’. If you’ve not encountered this gentleman, then you should – we can probably all learn a little from him in our eternal quest to big-up botany and help to...

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