Lepidothamnus

Abstract: The leaf arrangement and cuticular micromorphology of living species of the Podocarpaceae with an imbricate leaf arrangement demonstrates that generic determination is possible on this basis alone. This is of particular interest in Dacrydium, Halocarpus, Lepidothamnus and Lagarostrobos, which until recently were considered to be monogeneric. However, the two species of Lagarostrobos differ significantly from one another in these features, which further supports the view that these species should not be in the same genus. This study demonstrates the utility of this approach for determining the affinities of fossil imbricate-leaved podocarps which have only the vegetative parts preserved.

Abstract: The monotypic genus Manoao is erected to accommodate Lagarostrobos colensoi, silver pine, because the character-states of L. colensoi, endemic to New Zealand, and those of Huon pine, L. franklinii, endemic to Tasmania, are so divergent as to warrant treatment as separate genera distinct from Dacrydium and the other segregate genera Halocarpus and Lepidothamnus. As a consequence, Lagarostrobos is redefined to include the type and sole extant species, L. franklinii. The necessary new combination and transfer are made, and names previously assigned to both species are typified.

Abstract: Podocarpaceae is the largest family in cupressophytes (conifers II), but their plastid genomes (plastomes) are poorly studied, with plastome data currently existing for only four of the 19 Podocarpaceous genera. In this study, we assembled the plastomes from representatives of eight additional genera, including Afrocarpus , Dacrydium , Lagarostrobos , Lepidothamnus , Microstrobos , Phyllocladus , Prumnopitys , and Saxegothaea . We found that Lagarostrobos , a monotypic genus native to Tasmania, has the largest plastome among any cupressophytes studied to date (151,496 bp). Plastome enlargement in Lagarostrobos coincides with increased intergenic spacers, repeats, and duplicated genes. Among Podocarpaceae, Lagarostrobos has the most rearranged plastome, but its substitution rates are modest. Plastid phylogenomic analyses clarify the positions of previously conflicting Podocarpaceous genera. Tree topologies firmly support the division of Podocarpaceae into two sister clades: (1) the Prumnopityoid clade and (2) the clade containing Podocarpoid, Dacrydioid, Microstrobos , and Saxegothaea . The Phyllocladus is nested within the Podocarpaceae, thus familial status of the monotypic Phyllocladaceae is not supported.

Abstract: Dacrydium Sol. ex Lamb. emend. de Laub. is redefined to include only those species belonging to section B (Florin 1931; de Laubenfels 1969). The remaining species are assigned to Lepidothamnus Phil. (two species from New Zealand, one from Chile). Lagarostrobos gen. nov. (one species from New Zealand. one from Tasmania) and Halocarpus gen. nov. (three species from New Zealand). Ovule orientation, one of the main character-states used to define Dacrydium s.l., is reexamined and shown to be in accord with the new taxonomic arrangement. Lepidothamnus fonkii Phil. is reinstated and seven new combinations are made, viz. Lepidotharnnus intermedius (T. Kirk) C. J. Quinn, L. laxifolius (Hook. f.) C. J. Quinn, Halocarpus bidwillii (Hook. f. exT. Kirk) C. J. Quinn, H. biformis (Hook.) C. J . Quinn, H. kirkii (F. Muell. ex Parl.) C. J. Quinn, Lagarostrobos colensoi (Hook.) C. J . Quinn and L. franklinii (Hook. f.) C. J. Quinn. A key to the genera in the Podocarpaceae is also given.