Topic
Ixerba
About: Ixerba is a research topic. Over the lifetime, 3 publications have been published within this topic receiving 31 citations.
Papers
TL;DR: Evidence is presented in this paper that in Carpodetus serratus female flowers and hermaphrodite flowers occur on separate plants in approximately equal numbers in all populations studied.
Abstract: Summary It has been generally accepted that flowers of the three New Zealand genera of the Escalloniaceae (Carpodetus, Quintinia and Ixerba) are hermaphrodite (Allan, 1961). Evidence is presented in this paper that in Carpodetus serratus female flowers and hermaphrodite flowers (i.e. gynodioecism) occur on separate plants in approximately equal numbers in all populations studied. The majority of hermaphrodite plants bear no fruit, but in about 12% sparse fruiting occurs, which shows the gynoecium is potentially fertile. In Quintinia acutifolia female flowers with non-functional anthers are borne on about 40% of the plants; the rest bear male flowers in which the stigmatic lobes never develop fully and fruit is never found. Populations of Q. serrata and Q. elliptica have not been investigated, but male and female flowers have been observed in herbarium material of these species. The fifth New Zealand species, Ixerba brexioides is hermaphrodite.
13 citations
TL;DR: It is suggested that a high level of polyploidy may have allowed S. robusta to survive on a fragment of Gondwana by adapting to its ultrabasic substrate.
Abstract: We present the first report on the chromosome number of Strasburgeria robusta, which is confined to montane forests of New Caledonia and is the only known species in Strasburgeriaceae. The species has 2n = 500, which is an exceedingly high chromosome number in angiosperms. Within Crossosomatales, molecular evidence has indicated that S. robusta is sister to Ixerba brexioides, which is endemic to New Zealand and is the sole species in Ixerbaceae. Comparisons to the chromosome number of I. brexioides (2n = 50) support a close affinity between the two species because they share the base number x = 25. It is generally accepted that an increase in ploidy is associated with the origin of novel adaptations. A high level of polyploidy (20x with x = 25) may have allowed S. robusta to survive on a fragment of Gondwana by adapting to its ultrabasic substrate.
11 citations
TL;DR: The biology and ecology of the distinctive North Island New Zealand endemic tree Ixerba brexioides is summarized, including potential threats of climate change, susceptibility to inbreeding depression and the role of birds as dispersers.
Abstract: This review summarises the biology and ecology of the distinctive North Island New Zealand endemic tree Ixerba brexioides (A.Cunn.). The genus Ixerba is monotypic and belongs to the family Strasburgeriaceae found only in New Zealand and New Caledonia. Ixerba brexioides (tāwari) is a New Zealand tree restricted to rain forests north of 39°S latitude in areas of mature soil in mild, moist climates. With conspicuous white flowers displayed en masse between November and January each year and dark green, long and toothed leaves arranged in whorls, it has earned recognition as one of New Zealand’s most attractive trees. Inflorescences are predominantly insect pollinated, with occasional bird visitation. Capsular fruit are produced in early autumn and dehisce to reveal dark black-purple seeds with an orange fleshy aril that are bird dispersed. Seeds germinate quickly, without a dormancy period, most commonly on soil, logs and mounds, but grow slowly (1.6–2.4 mm year diameter growth rate) in shade conditi...
8 citations
Related Topics (5)
Performance Metrics
| Year | Papers |
|---|---|
| 2017 | 1 |
| 2006 | 1 |
| 1969 | 1 |