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Petaloid organs are a major component of the floral diversity observed across nearly all major clades of angiosperms. The variable morphology and development of these organs has led to the hypothesis that they are not homologous but, rather, have evolved multiple times. A particularly notable example of petal diversity, and potential homoplasy, is found within the order Ranunculales, exemplified by families such as Ranunculaceae, Berberidaceae, and Papaveraceae. To investigate the molecular basis of petal identity in Ranunculales, we used a combination of molecular phylogenetics and gene expression analysis to characterize APETALA3 (AP3) and PISTILLATA (PI) homologs from a total of 13 representative genera of the order. One of the most striking results of this study is that expression of orthologs of a single AP3 lineage is consistently petal-specific across both Ranunculaceae and Berberidaceae. We conclude from this finding that these supposedly homoplastic petals in fact share a developmental genetic program that appears to have been present in the common ancestor of the two families. We discuss the implications of this type of molecular data for long-held typological definitions of petals and, more broadly, the evolution of petaloid organs across the angiosperms. Key words: APETALA3; MADS box genes; petal evolution; PISTILLATA; Ranunculales.

Gomortega keule (Molina) Baillon is a rare Chilean species classified as endangered and currently under conservation. Currently, conservation of this species is carried out by private companies and government agencies, but is done so based more on pragmatic criteria than scientifically based strategies. In this context, information concerning the genetic variability of the species among the different populations over its entire distribution range is incomplete, making it difficult to coordinate management and conservation strategies. Here we report a study to evaluate the genetic variability and population structure of G. keule over its entire distribution in Chile. Twenty-five ISSR primers for 223 individuals from 11 geographical populations were tested to evaluate genetic variability. Results showed a high level of genetic diversity for the species. A high level of genetic differentiation among populations was found, while genetic structure of the geographic populations was also shown by using STRUCTURE 2.1 software. Despite the fact that this species has been highly affected by human intervention and habitat destruction, a high level of genetic diversity was present. A likely explanation for this is that it reflects the previous distribution of this long-lived species and the current lack of sexual regeneration. Genetic diversity data must be considered in the development of a management strategy for further developing the protected areas, for identifying isolated small populations for conservation, and using larger populations with higher genetic diversity as seed sources for ex situ propagation and replanting. Key words: genetic fragmentation, genetic diversity, Gomortega keule, ISSR markers, tree conservation. Le Gomortega keule (Molina) Baillon constitue une espece rare menacee, presentement en observation. Actuellement, des entreprises privees et gouvernementales en assurent la conservation sur la base de criteres pragmatiques plutot que scientifiques. Ainsi, l'information sur la variabilite genetique de cette espece dans les differentes populations et sur l'ensemble de son aire de distribution demeure incomplete, ce qui rend difficile la coordination des strategies d'amenagement et de conservation. Les auteurs ont effectue une etude sur la variabilite genetique et les structures des populations G. keule, sur l'ensemble de son aire de distribution au Chili. Ils ont evalue 25 amorces ISSR sur 223 individus provenant de 11 populations geographiques, afin d'en determiner la variabilite genetique. Les resultats montrent une grande variabilite genetique chez cette espece. On observe egalement un haut degre de differenciation genetique au sein des populations ainsi que dans la structure genetique des populations geographiques, en utilisant le logiciel STRUCTURE 2.1. En depit du fait que cette espece ait ete fortement affectee par l'activite humaine, notamment la destruction d'habitats, on observe toujours un fort degre de diversite genetique. Ce qui pourrait expliquer cette situation, c'est qu'elle reflete la distribution ancienne de cette espece longivive ainsi que le manque de regeneration sexuelle actuel. On doit considerer les donnees sur la diversite genetique lorsqu'on developpe des strategies d'amenagement pour implanter de nouveaux sites de protection, afin d'identifier les petites populations isolees pour leur conservation, et en utilisant les populations plus etendues avec une plus forte diversite genetique comme sources de semences pour la propagation ex situ et la transplantation. Mots-cles : fragmentation genetique, diversite genetique, Gomortega keule, marqueurs ISSR, conservation des arbres. [Traduit par la Redaction], Introduction To understand the genetic status of tree populations it is necessary to study not only the genetic diversity patterns among populations (Herrera et al. 2005), but also the current [...]

Byline: Seishiro Aoki (1), Koichi Uehara (2), Masao Imafuku (3), Mitsuyasu Hasebe (4,5), Motomi Ito (3) Keywords: Amborella; Floral homeotic genes; Illicium; Kadsura; MADS; Nymphaeales Abstract: The B-class MADS-box genes composed of APETALA3 (AP3) and PISTILLATA (PI) lineages play an important role in petal and stamen identity in previously studied flowering plants. We investigated the diversification of the AP3-like and PI-like MADS-box genes of eight species in five basal angiosperm families: Amborella trichopoda (Amborellaceae) Brasenia schreberi and Cabomba caroliniana (Cabombaceae) Euryale ferox, Nuphar japonicum, and Nymphaea tetragona (Nymphaeaceae) Illicium anisatum (Illiciaceae) and Kadsura japonica (Schisandraceae). Sequence analysis showed that a four amino acid deletion in the K domain, which was found in all previously reported angiosperm PI genes, exists in a PI homologue of Schisandraceae, but not in six PI homologues of the Amborellaceae, Cabombaceae, and Nymphaeaceae, suggesting that the Amborellaceae, Cabombaceae, and Nymphaeaceae are basalmost lineages in angiosperms. The results of molecular phylogenetic analyses were not inconsistent with this hypothesis. The AP3 and PI homologues from Amborella share a sequence of five amino acids in the 5 region of exon 7. Using the linearized tree and likelihood methods, the divergence time between the AP3 and PI lineages was estimated as somewhere between immediately after to several tens of millions of years after the split between angiosperms and extant gymnosperms. Estimates of the age of the most recent common ancestor of all extant angiosperms range from ~140--210 Ma, depending on the trees used and assumptions made. Author Affiliation: (1) Department of Life Sciences, Graduate School of Arts and Sciences, University of Tokyo, 3-8-1 Komaba, Meguro-ku, Tokyo 153-8902, Japan (2) Faculty of Horticulture, Chiba University, Chiba, Japan (3) Graduate School of Arts and Sciences, University of Tokyo, Tokyo, Japan (4) National Institute for Basic Biology, Okazaki, Japan (5) Department of Molecular Biomechanics, The Graduate University for Advanced Studies, Okazaki, Japan Article History: Registration Date: 17/03/2004 Received Date: 29/12/2003 Accepted Date: 10/03/2004 Online Date: 12/05/2004

Myristicaceae (Magnoliales) consist of 20 genera and nearly 500 species of lowland rainforest trees with a pantropical distribution. They are distinctive in having small, unisexual flowers with stamens fused into a synandrium, which consists of a single whorl of sessile anthers borne around a sterile central column. With its short filaments and more complex anther phyllotaxy, the Malagasy genus Mauloutchia represents a notable exception to this pattern. New scanning electron microscope (SEM) examinaitons of Brochoneura, Cephalosphaera, Knema, Mauloutchia, and Staudtia are incorporated into a broader review of androecium diversity across the family. These new results are discussed in the context of a phylogenetic study of the family, based on combined molecular and morphological data. The unusual synandrium of Mauloutchia, nested among genera with strictly sessile anthers fused to the column, appears to be secondarily derived. Furthermore, the diversity of patterns observed within the genus may be interpreted as the result of a stepwise transformation involving reappearance and elongation of filaments, increase of anther number, and modification of anther phyllotaxy. However, the question of the origin of stamen fusion in Myristicaceae remains unanswered and requires more developmental studies. Finally, a new Malagasy genus of Myristicaceae (Doyleanthus) is described, which is similar to Mauloutchia in most characters but fundamentally different in androecial traits. Key words: androecium evolution; Brochoneura; Cephalosphaera; Doyleanthus; Magnoliales; Mauloutchia; Myristicaceae; stamen evolution; Staudtia.