For cycads, molecular phylogenies were previously constructed using two chloroplast genes and nrDNA roplast genes and associated noncoding regions. All of the phylogenies support the basal position of Cycas and the devition of cycads into two families, which have been recognized in the new book. That is, Cycadaceae comprises the single genus Cycas, while Zamiaceae includes the rest of nine genera. However, some intergeneric relationships within the family Zamiaceae, especially the phylogenetic positions of Bowenia, Dioon and Stangeria, still remain unresolved, although the genus Dioon was placed in a basal positions in most phylogenies. Very recently, a relatively solid phylogeny of cycads was reconstructed using five single-copy nuclear genes, in which, for Zamiaceae, Dioon diverged first, followed by Bowenia
,and then an encephalartoid clade sister to a zamioid clade.
For cycads, molecular phylogenies were previously constructed using two chloroplast genes and nrDNA roplast genes and associated noncoding regions. All of the phylogenies support the basal position of Cycas and the devition of cycads into two families, which have been recognized in the new book. That is, Cycadaceae comprises the single genus Cycas, while Zamiaceae includes the rest of nine genera. However, some intergeneric relationships within the family Zamiaceae, especially the phylogenetic positions of Bowenia, Dioon and Stangeria, still remain unresolved, although the genus Dioon was placed in a basal positions in most phylogenies. Very recently, a relatively solid phylogeny of cycads was reconstructed using five single-copy nuclear genes, in which, for Zamiaceae, Dioon diverged first, followed by Bowenia
,and then an encephalartoid clade sister to a zamioid clade.
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