Cytoevolution, Phylogeny and Taxonomy in Epacridaceae

Stace, Helen M.; Chapman, Alex R.; Lemson, Kristina L.; Powell, Jocelyn

doi:10.1006/anbo.1996.0333

Cited by 23 publications

(5 citation statements)

References 24 publications

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“…However, recent phylogenetic studies (Powell et al, 1996;Stace et al, 1997;Kron et al, 2002) revealed that the epacrids form a well-supported monophyletic group nested within the Ericaceae. As a consequence, they have all been transferred to the family Ericaceae, and the epacrids are now recognized as a distinct subfamily, the Styphelioideae Sweet.…”

mentioning

confidence: 99%

Origin, Diversification, and Classification of the Australasian Genus Dracophyllum (Richeeae, Ericaceae)¹

Wagstaff¹,

Dawson²,

Venter³

et al. 2010

Annals of the Missouri Botanical Garden

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The genus Dracophyllum Labill. (Ericaceae) has a fragmented distribution in Australasia, but reaches the greatest level of species richness and morphological diversity in New Zealand. We investigated evolutionary processes that contribute to this disparity in species richness by comparing DNA sequences from members of Dracophyllum, its close relatives Richea Labill. and Sphenotoma R. Br. ex Sweet (together constituting tribe Richeeae Crayn & Quinn), along with more distant relatives in the Ericaceae. We created complementary data sets for the chloroplast-encoded genes matK and rbcL. Parsimony, Bayesian, and maximum likelihood analyses were conducted to assess the robustness of our phylogenetic inferences. The results were largely congruent and, when analyzed in combination, provided greater resolution. In our analyses, tribe Richeeae formed a monophyletic group that diverged during the Eocene (at least 33.3 million years ago [Ma]) with a crown radiation during the Early Miocene (at least 16.5 Ma) that resulted in two disjunct lineages. This date corresponds roughly to the onset of aridification in central Australia. The southern Western Australian genus Sphenotoma formed an isolated evolutionary lineage, while Dracophyllum and Richea together formed a second lineage restricted to eastern Australia, Lord Howe Island, New Caledonia, and New Zealand. The relationships of the Tasmanian endemic, D. milliganii Hook. f., remain an enigma. It was ambiguously placed as sister to Sphenotoma or to the Dracophyllum-Richea clade. We recovered two distinct lineages, traditionally recognized as Richea sect. Cystanthe (R. Br.) Benth. and Richea sect. Dracophylloides Benth., which were nested within Dracophyllum. The Lord Howe Island endemic, D. fitzgeraldii F. Muell., emerged as sister to an eastern Australian clade of Dracophyllum. Our evidence suggests that the New Caledonian and New Zealand species of Dracophyllum dispersed from Australia; we document two independent episodes of long-distance dispersal in the Late Miocene to Early Pliocene. Low levels of sequence divergence suggest a rapid and recent species radiation in these two island archipelagos largely within the last three to six million years. This radiation accompanied Pliocene uplift of the New Zealand Southern Alps and episodes of glaciation during the Pleistocene. Because Dracophyllum is paraphyletic and Richea is polyphyletic, the taxonomic circumscription of these genera requires revision.

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confidence: 99%

Origin, Diversification, and Classification of the Australasian Genus Dracophyllum (Richeeae, Ericaceae)¹

Wagstaff¹,

Dawson²,

Venter³

et al. 2010

Annals of the Missouri Botanical Garden

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“…Such studies include Stace et al . (1993 ) (Rutaceae); Stace & James (1996) (Lobelioideae); Stace et al . (1997 ) (Epacridaceae).…”

Section: Discussionunclassified

Genomic coalescence in a population of Laxmannia sessiliflora (Angiospermae, Anthericaceae): an association of lethal polymorphism, self-pollination and chromosome number reduction

et al. 1999

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A population of Laxmannia R. Br. (Angiospermae, Anthericaceae) near Collie, Western Australia, combines the taxonomically significant sessile inflorescences of L. sessiliflora Dcne. (n = 4) and the derived breeding system of L. ramosa Lindl. (n = 4). It exhibits a polymorphism for seed‐aborting lethal equivalents, significant levels of self‐pollination and a chromosome polymorphism in which a haploid genome with n = 3 is most frequent. Allozyme analysis indicates that the population is either of hybrid origin or one that has uniquely diverged from a phylogenetic link between the two species. The population is considered to represent a natural demonstration of the phenomenon of genomic coalescence as modelled by James (1992, Heredity, 68 , 449–456) in which devices which reduce the number of independently segregating supergenes heterozygous for recessive lethals are elevated to high frequencies by inbreeding. The population also suggests a mechanism whereby dysploid chromosome number reduction may be promoted by natural selection in natural population systems.

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“…Chromosome numbers are variable in the subfamily, though the situation is more complex than in sedges, and various patterns have been described. There has probably been reduction in chromosome number from an ancestral karyotype of x = 12 or x = 13, but there are contrasting reports of diploid chromosome number in some genera (Stace et al 1997). In some epacrids, from one to four of the products of male meiosis degenerate, producing triads, dyads, monads, and sometimes even sterile ''nullads'' (Smith-White 1955, 1959Furness 2009).…”

Section: Variable Microsporogenesis In Epacridsmentioning

confidence: 95%

Selective microspore abortion correlated with aneuploidy: an indication of meiotic drive

Furness

Rudall

2010

Sex Plant Reprod

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Selective megaspore abortion (monomegaspory) probably arose once in seed plants and occurs routinely in more than 70% of angiosperm species, representing one of the key characters of a heterosporous life history. In contrast, selective microspore abortion leading to pollen dispersal as pseudomonads (here termed monomicrospory) apparently arose at least twice independently within angiosperms, though it occurs in a limited number of taxa. Remarkably, similar examples of monomicrospory occur in members of two distantly related angiosperm families: the sedge family (Cyperaceae) and the epacrid subfamily (Styphelioideae) of the eudicot family Ericaceae. In sedges, monomicrospory is derived directly from normal tetrads, whereas epacrid pseudomonads apparently evolved via an intermediate stage, in which variable sterility occurs in a single tetrad. Our comparison of these two examples of selective microspore abortion highlights a correlation with aneuploidy, indicating that non-random chromosome segregation caused by monomicrospory could drive chromosomal mutations to rapid fixation through meiotic drive.

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Cytoevolution, Phylogeny and Taxonomy in Epacridaceae

Cited by 23 publications

References 24 publications

Origin, Diversification, and Classification of the Australasian Genus Dracophyllum (Richeeae, Ericaceae)¹

Origin, Diversification, and Classification of the Australasian Genus Dracophyllum (Richeeae, Ericaceae)¹

Genomic coalescence in a population of Laxmannia sessiliflora (Angiospermae, Anthericaceae): an association of lethal polymorphism, self-pollination and chromosome number reduction

Selective microspore abortion correlated with aneuploidy: an indication of meiotic drive

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Cytoevolution, Phylogeny and Taxonomy in Epacridaceae

Cited by 23 publications

References 24 publications

Origin, Diversification, and Classification of the Australasian Genus Dracophyllum (Richeeae, Ericaceae)1

Origin, Diversification, and Classification of the Australasian Genus Dracophyllum (Richeeae, Ericaceae)1

Genomic coalescence in a population of Laxmannia sessiliflora (Angiospermae, Anthericaceae): an association of lethal polymorphism, self-pollination and chromosome number reduction

Selective microspore abortion correlated with aneuploidy: an indication of meiotic drive

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Origin, Diversification, and Classification of the Australasian Genus Dracophyllum (Richeeae, Ericaceae)¹

Origin, Diversification, and Classification of the Australasian Genus Dracophyllum (Richeeae, Ericaceae)¹