10.5061/DRYAD.8013
Humphreys, Aelys Muriel
University of Zurich
Antonelli, Alexandre
University of Zurich
Pirie, Michael D.
University of Zurich
Linder, H. Peter
University of Zurich
Data from: Ecology and evolution of the diaspore 'burial syndrome'
Dryad
dataset
2010
Danthonioideae
character loss
2010-11-24T21:13:11Z
2010-11-24T21:13:11Z
en
https://doi.org/10.1111/j.1558-5646.2010.01184.x
63488 bytes
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CC0 1.0 Universal (CC0 1.0) Public Domain Dedication
Hygroscopically active awns or "bristles" have long intrigued
scientists. Experimental evidence shows that they are important for
diaspore burial in the correct orientation, thereby increasing successful
seed germination and seedling survival. Despite these ecological
advantages, 38 of the 280 species of grasses in Danthonioideae lack awns.
We provide the first study of awns in a phylogenetic context and show that
whilst the awnless state has arisen ca. 25 times independently, the
ecological disadvantage of not having an awn also applies in an
evolutionary context. Only in Tribolium and Schismus have awnless
ancestors diversified to form a clade of primarily awnless descendents.
Several of the awnless species in these genera are annual and we find a
significant correlation between the evolution of awns and the evolution of
life history. A suite of other diaspore traits accompany the awned or
awnless states. We interpret the awn as being the visible constituent of a
compound "burial syndrome", the two ecological extremes of which
may explain the correlation between awns and life history and provide an
explanation why awnless species in Tribolium and Schismus persist.
Appendix_ICharacter states and callus lengths for each species. The
species are the 280 species of Danthonioideae (Poaceae). Characters are
awns, lemma indumentum, callus indumentum, callus length and life history.
Awns are coded as present (0) or absent (1). Absence of an awn denotes
species in which the awn is altogether absent or reduced to a ‘mucro’,
i.e. reduced beyond hygroscopic function. Callus and lemma indumentum are
coded as villous (0) or glabrous (1), with ‘glabrous’ coded only for those
species that never produce hairs on these surfaces. Polymorphic species
are coded as (0). Life history was coded as perennial (0) or annual (1).
Four species of Pentameris are biannual and these were coded as perennial
to distinguish species that survive as adult plants for more than one
growing season from those that do not.