J. Bogner, K.R. Johnson, Z. Kvacek, G.R. Upchurch (2007). New fossil leaves of Araceae from the Late Cretaceous and Paleogene of western North America. Zitteliana A47: 133-147. Reprint requests should be directed to kvacek@natur.cuni.cz
Three new species are described from the leaves: Orontium wolfei (Eocene), Orontium mackii (Cretaceous-Maastrichtian), Symplocarpus hoffmaniae (Cretaceous-Maastrichtian and Palaeocene); a new combination Lysichiton austriacus is made (Cretaceous-Campanian).
These are all new additions to the Subfamily Orontioideae. This paper, as with previous papers on leaf fossils of aroids, underlines the need to develop new comparative studies of the leaf venation patterns of extant genera of aroids, so that quantitative comparisons with leaf fossils can be made in the future.
Fossil aroids have become a really active and exciting research area in the past 15 years. It seems to me that the fossil taxa should be incorporated into the main species sequence,particularly given their importance for dating phylogenetic studies.
Dear Cesar,
The most complete study yet made was P.O. Ertl (1932), Vergleichende Untersuchungen ueber die Entwicklung der Blattnervatur der Araceen. Flora 126: 115 - 248.
("Comparative investigations of the development of leaf venation in Araceae").
I think this study arose from the fact that Engler, whose system was then the dominant one for aroids, used leaf architecture as an important character for differentiating subfamilies. Maybe Ertl was probing this.
Ertl studied leaf development by looking at the venation and blade growth in very young leaves and his conclusion was that there were no really fundamental differences between the types recognized by taxonomists.
Well, although that sounds a bit disheartening it doesn't change the fact that aroid taxonomists continue to use leaf venation as a really useful character field. So this is a field that needs new research. It would be great if more people got interested in this, as it would also help the fossil botanists to classify their finds.
Dear Cesar,
There is a very interesting paper by Plotze et al. 2005. Leaf shape analysis using the multiscale Minkowski fractal dimension, a new morphometric method: a study with Passiflora (Passifloraceae). Canad. J. Bot. 83: 287-301. This is a method for analysing outline shapes and major venation patterns simultaneously, and as far as I know is the only such technique to have been successfully applied to plant leaves. It's a Brazilian research group and the corresponding email is jgpadua@esalq.usp.br
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A paper on fossil aroids was published recently:-
J. Bogner, K.R. Johnson, Z. Kvacek, G.R. Upchurch (2007). New fossil leaves of Araceae from the Late Cretaceous and Paleogene of western North America. Zitteliana A47: 133-147. Reprint requests should be directed to kvacek@natur.cuni.cz
Three new species are described from the leaves: Orontium wolfei (Eocene), Orontium mackii (Cretaceous-Maastrichtian), Symplocarpus hoffmaniae (Cretaceous-Maastrichtian and Palaeocene); a new combination Lysichiton austriacus is made (Cretaceous-Campanian).
These are all new additions to the Subfamily Orontioideae. This paper, as with previous papers on leaf fossils of aroids, underlines the need to develop new comparative studies of the leaf venation patterns of extant genera of aroids, so that quantitative comparisons with leaf fossils can be made in the future.
Fossil aroids have become a really active and exciting research area in the past 15 years. It seems to me that the fossil taxa should be incorporated into the main species sequence,particularly given their importance for dating phylogenetic studies.
Has anyone tried characterizing the leaf architecture (morphology and venation) of Aroids?
Dear Cesar,
The most complete study yet made was P.O. Ertl (1932), Vergleichende Untersuchungen ueber die Entwicklung der Blattnervatur der Araceen. Flora 126: 115 - 248.
("Comparative investigations of the development of leaf venation in Araceae").
I think this study arose from the fact that Engler, whose system was then the dominant one for aroids, used leaf architecture as an important character for differentiating subfamilies. Maybe Ertl was probing this.
Ertl studied leaf development by looking at the venation and blade growth in very young leaves and his conclusion was that there were no really fundamental differences between the types recognized by taxonomists.
Well, although that sounds a bit disheartening it doesn't change the fact that aroid taxonomists continue to use leaf venation as a really useful character field. So this is a field that needs new research. It would be great if more people got interested in this, as it would also help the fossil botanists to classify their finds.
Dear Cesar,
There is a very interesting paper by Plotze et al. 2005. Leaf shape analysis using the multiscale Minkowski fractal dimension, a new morphometric method: a study with Passiflora (Passifloraceae). Canad. J. Bot. 83: 287-301. This is a method for analysing outline shapes and major venation patterns simultaneously, and as far as I know is the only such technique to have been successfully applied to plant leaves. It's a Brazilian research group and the corresponding email is jgpadua@esalq.usp.br
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