Morphological diversity and evolution of Centrolepidaceae (Poales), a species-poor clade with diverse body plans and developmental patterns.
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OBJECTIVE
The small primarily Australian commelinid monocot family Centrolepidaceae displays remarkably high structural diversity that has been hitherto relatively poorly explored. Data on Centrolepidaceae are important for comparison with other Poales, including grasses and sedges.•


METHODS
We examined vegetative and reproductive morphology in a global survey of Centrolepidaceae based on light and scanning electron microscopy of 18 species, representing all three genera. We used these data to perform a cladistic analysis to assess character evolution.•


RESULTS
Each of the three genera is monophyletic; Centrolepis is sister to Aphelia. Some Centrolepidaceae show a change from spiral to distichous phyllotaxy on inflorescence transition. In Aphelia and most species of Centrolepis, several morphologically distinct leaf types develop along the primary shoot axis and flowers are confined to dorsiventral lateral spikelets. Centrolepis racemosa displays secondary unification of programs of leaf development, absence of the leaf hyperphyll and loss of shoot dimorphism. Presence or absence of a leaf ligule and features of inflorescence and flower morphology are useful as phylogenetic characters in Centrolepidaceae.•


CONCLUSIONS
Ontogenetic changes in phyllotaxy differ fundamentally between some Centrolepidaceae and many grasses. Inferred evolutionary transformations of phyllotaxy in Centrolepidaceae inflorescences also differ from those in grasses. In contrast with grasses, some Centrolepidaceae possess ligulate leaves where the ligule represents the boundary between the bifacial hypophyll and unifacial hyperphyll. All the highly unusual features of the morphological-misfit species Centrolepis racemosa could result from the same saltational event. Centrolepidaceae offer good perspectives for studies of evolutionary developmental biology.
Department of Higher Plants, Faculty of Biology, Lomonosov Moscow State University, Moscow 119234, Russia.
Dmitry D
DD
Sokoloff
Department of Higher Plants, Faculty of Biology, Lomonosov Moscow State University, Moscow 119234, Russia.
Margarita V
MV
Remizowa
Botanic Gardens & Parks Authority, West Perth 6005, Western Australia School of Plant Biology, Faculty of Natural and Agricultural Sciences, The University of Western Australia, Crawley, 6009, Western Australia Western Australian Herbarium, Department of Environment and Conservation, Locked Bag 104, Bentley Delivery Centre, 6983, Western Australia.
Matthew D
MD
Barrett
ACEBB & SGC, School of Biological Sciences, Benham Bldg DX 650 312, The University of Adelaide, SA 5005 Australia.
John G
JG
Conran
Royal Botanic Gardens, Kew, Richmond, Surrey TW9 3AB, UK.
Paula J
PJ
Rudall
D001315:Australia; D005075:Biological Evolution; D019432:Falkland Islands; D035264:Flowers / Q000648:ultrastructure; D056626:Inflorescence / Q000648:ultrastructure; D019684:Magnoliopsida / Q000145:classification* / Q000254:growth & development / Q000648:ultrastructure*; D008855:Microscopy, Electron, Scanning; D010802:Phylogeny
Centrolepidaceae; bract; development; evolution; flower; fruit; grasses; inflorescence; leaf; tepal