Awn length variation in Australia’s most widespread grass, Themeda triandra, across its distribution

Annette M. Cavanagh; Robert C. Godfree; John W. Morgan

doi:10.1071/BT23083

RESEARCH ARTICLE (Open Access)

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Awn length variation in Australia’s most widespread grass, Themeda triandra, across its distribution

Annette M. Cavanagh

^A ^* , Robert C. Godfree ^B and John W. Morgan

^A

+ Author Affiliations

- Author Affiliations

^A Department of Environment and Genetics, La Trobe University, Bundoora, Vic. 3086, Australia.

^B National Research Collections Australia, CSIRO, Canberra, ACT, Australia.

^* Correspondence to: a.m.cavanagh@outlook.com.au

Handling Editor: Andrew Denham

Australian Journal of Botany 72, BT23083 https://doi.org/10.1071/BT23083

Submitted: 2 October 2023 Accepted: 1 March 2024 Published: 21 March 2024

© 2024 The Author(s) (or their employer(s)). Published by CSIRO Publishing. This is an open access article distributed under the Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International License (CC BY-NC-ND)

Abstract

Themeda triandra (kangaroo grass) is the most widespread plant species in Australia. Using herbarium specimens, we quantified awn-length variation across its distribution in relation to climate. We found that awn lengths were shortest around the eastern and southern coast of Australia (with short awns also concentrated in the Pilbara), increasing in length progressively inland and towards the north. There was a significant positive relationship between awn length and mean annual temperature. Further research is needed to understand why awn lengths vary, and how awn-length variation affects seed and seedling fitness in natural habitats.

Keywords: biogeography, grasses, grasslands, plant adaptation, plant ecology, Poaceae, polyploidy, seed ecology.

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