An awn typology for Australian native grasses (Poaceae)

被引:15
作者
Cavanagh, Annette M. [1 ]
Godfree, Robert C. [2 ]
Morgan, John W. [1 ]
机构
[1] La Trobe Univ, Dept Ecol Environm & Evolut, Bundoora, Vic 3086, Australia
[2] CSIRO Natl Res Collect Australia, GPO Box 1700, Canberra, ACT 2601, Australia
关键词
diaspore; dispersal; hygroscopic; morphology; SEED-DISPERSAL UNITS; BIOLOGICAL SIGNIFICANCE; LENGTH VARIATION; SELF-BURIAL; MORPHOLOGY; SOIL; ESTABLISHMENT; MECHANICS; BEHAVIOR;
D O I
10.1071/BT18216
中图分类号
Q94 [植物学];
学科分类号
071001 ;
摘要
Australia has a large diversity of native grasses. The diaspores of many species possess awns that vary considerably in their number and shape. Some variations of awn shape have been found to be effective at diaspore dispersal. Although morphological descriptions of awns exist for most native grass species, the number of species that possess awns and the extent of awn variation is unknown. This makes it difficult to determine the evolutionary importance of awns and the potential function of the various morphologies. The aim of this study was to construct an awn typology based on morphological descriptions collated from published flora databases that will quantify the awn type diversity of all native grass species in Australia, and will inform awn type relationships and help to clarify the role of differing awn morphologies in diaspore dispersal. We found that 42.1% of 1000 Australian native grasses with a single awn type were determined to have a 'significant' awn. These could be classified into one of 20 awn types, the most common being (1) single, apical, geniculate (once-sharply bent) awns (93 species; 28 genera, especially Iseilema), (2) three, apically-attached, straight awns (59 species, mainly Aristida) and (3) single, apical, bigeniculate (twice-sharply bent) awns (46 species, mainly Austrostipa). Among Australian grasses, slightly (though significantly) more C-3 species (49.2%) had awns than C-4 species (39.9%), although the most common awn types in both contained sharply bent awns (bigeniculate and geniculate respectively). Our classification system will help to improve our understanding of the amount of awn morphological variation in Australian grasses and will enable further investigation into the important ecological role of awns in species fitness.
引用
收藏
页码:309 / 334
页数:26
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