Topic
Halocarpus
About: Halocarpus is a research topic. Over the lifetime, 11 publications have been published within this topic receiving 341 citations.
Papers
TL;DR: Well-preserved macrofossils and pollen from three sites in southern New Zealand suggest that the floras in Eocene, Oligocene and Miocene times were much more diverse at the generic level.
Abstract: The modern New Zealand flora has a relatively low number of families and genera in relation to land area, but well-preserved macrofossils and pollen from three sites in southern New Zealand suggest that the floras in Eocene, Oligocene and Miocene times were much more diverse at the generic level. At Pikopiko, Southland, a late Eocene in situ forest with fern understory was dominated by conifers, Casuarinaceae, Lauraceae, Nothofagus, Proteaceae, and mesothermal angiosperms including palms (aff. Calamus), Sapindaceae: Cupaniae and Picrodendraceae. At Newvale Mine, Southland, a leaf bed within a thick lignite seam represents leaf fossils preserved in a late Oligocene oligotrophic bog. This site demonstrates that Agathis, Dacrycarpus, Dacrydium, Halocarpus, Microcachrys, Podocarpus and Phyllocladus coexisted with diverse angiosperms including Nothofagus, Gymnostoma, Cunoniaceae, Ericaceae, Sapindaceae and several Proteaceae. Pollen data add Meliaceae, Myrtaceae, Onagraceae and Rubiaceae to the flora. At Foulden Maar, Otago, mummified leaves and flowers, including several with in situ pollen, demonstrate the existence of a diverse flora surrounding an Early Miocene lake. This site contains numerous monocot macrofossils including Astelia, Cordyline, Ripogonum and Typha, as well as the oldest fossils known for Orchidaceae and Luzuriagaceae. This flora was dominated by Lauraceae with affinities to Cryptocarya and Litsea, but other families include Araliaceae, Cunoniaceae, Elaeocarpaceae, Euphorbiaceae sensu lato, Menispermaceae, Myrsinaceae, Myrtaceae, Onagraceae, Proteaceae and Sterculiaceae. Many ferns, conifers, and Nothofagus are from lineages with Gondwanan ancestors, whereas other taxa show links to Australia (e.g., Gyrostemonaceae), New Caledonia (e.g., Beauprea) and South America (e.g., Luzuriaga, Fuchsia). Many of these taxa are now extinct in New Zealand, and therefore indicate much wider biogeographic ranges for many families and genera in the past.
81 citations
TL;DR: The results indicate that Podocarpaceae are polyphyletic unless expanded to include Phyllocladaceae, and jackknife support values indicate that although the genera are well supported, relationships both within and between them are not, suggesting that intergeneric relationships in the family require further study.
Abstract: Analysis of sequences of the chloroplast gene rbcL for 76 taxa of Podocarpaceae (representing all genera except Parasitaxus) and five species of Phyllocladaceae were undertaken with respect to their relationships to each other and to 28 coniferalean outgroup taxa from seven families. The results indicate that Podocarpaceae are polyphyletic unless expanded to include Phyllocladaceae. Within Podocarpaceae, Sundacarpus is placed in a clade with Prumnopitys, and Falcatifolium is paraphyletic as a basal grade to Dacrydium. Phyllocladus is in an unresloved clade with Halocarpus, Manoao/Lagarostrobos and Prumnopitys/Sundacarpus. The separation of Afrocarpus from Podocarpus and its placement instead as sister to Nageia and Retrophyllum is supported. Podocarpus s. str. is monophyletic, with both subgenera identified, albeit poorly supported. The analysis placed Lepidothamnus and Saxegothaea in an unresolved basal polytomy within the family. There were no clear outgroup relationships with the family. These results differ from the morphological clades found by Kelch (1997), and disagree strongly with his 18S-sequence-based phylogeny (Kelch 1998). However, jackknife support values indicate that although the genera are well supported, relationships both within and between them are not, suggesting that intergeneric relationships in the family require further study. There is also some congruence between our results and those of the gymnosperm 18S study by Chaw et al. (1997), although their study included only three Podocarpaceae and one Phyllocladaceae species.
72 citations
TL;DR: 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 and supports the view that these species should not be in the same genus.
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.
55 citations
TL;DR: The monotypic genus Manoao is erected to accommodate Lagarostrobos colensoi, silver pine, because the character-states of L. colen soi and L. franklinii are so divergent as to warrant treatment as separate genera distinct from Dacrydium and the other segregate genera Halocarpus and Lepidothamnus.
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.
54 citations
TL;DR: Fossils from the late Oligocene or early Miocene Newvale site, South Island, New Zealand, indicate that the late Paleogene to early Neogene conifer flora of New Zealand was very diverse, with all but one of the extant genera present, together with several regionally or globally extinct genera, and multiple species of many of these genera.
Abstract: Eight species of Podocarpaceae foliage are recognised from the late Oligocene or early Miocene Newvale site, South Island, New Zealand, and the following five new species are described: two of Dacrydium Lamb. and one each of Dacrycarpus (Endl.) de Laub., Phyllocladus Rich. ex Mirb. and Halocarpus Quinn. The latter is the first macrofossil record of this New Zealand endemic genus. All these conifers, plus Agathis Salisb., Microcachrys Hook.f. and Podocarpus Pers., co-occurred in the local vegetation at Newvale. In conjunction with prior records of macrofossils and pollen, these fossils indicate that the late Paleogene to early Neogene conifer flora of New Zealand was very diverse, with all but one of the extant genera present, together with several regionally or globally extinct genera, and multiple species of many of these genera. This fossil diversity is similar to the Paleogene fossil conifer diversity observed in south-eastern Australia (and particularly Tasmania) and in parts of North America.
41 citations
Related Topics (5)
Performance Metrics
| Year | Papers |
|---|---|
| 2012 | 1 |
| 2011 | 1 |
| 2000 | 1 |
| 1998 | 1 |
| 1995 | 2 |
| 1993 | 1 |