Publication
Title
**_Amphistemon** and **Thamnoldenlandia**, two new genera of Rubiaceae (Spermacoceae) endemic to Madagascar
Author
Abstract
Amphistemon and Thamnoldenlandia are described as two new genera of Rubiaceae endemic to Madagascar. The two novelties belong to the predominantly herbaceous tribe Spermacoceae. Amphistemon is unique within the tribe in having its stamens inserted at two levels in the corolla tube. The genus includes two species: the subshrub A. humbertii and the geoxylic herb A. rakotonasolianus. Thamnoldenlandia includes only one species, T. ambovombensis, which differs from most other Spermacoceae in being a medium-sized shrub with winged seeds. We present a detailed description of Amphistemon and Thamnoldenlandia, including observations of pollen and seeds. A molecular phylogenetic study based on atpB-rbcL, petD, rps16 and trnL-trnF sequences demonstrates that the two new genera belong to the HedyotisOldenlandia complex of tribe Spermacoceae. Amphistemon and Thamnoldenlandia are sister taxa and share a common ancestor with the Madagascan endemic genus Astiella. A second, but not closely related, Madagascan clade includes the endemic genera Lathraeocarpa and Gomphocalyx and the Afro-Madagascan genus Phylohydrax. This indicates that the Madagascan endemic members of Spermacoceae are the result of at least two independent colonization events, most likely by long-distance dispersal from the African mainland.
Language
English
Source (journal)
Botanical journal of the Linnean Society / Linnean Society of London. - London
Publication
London : 2010
ISSN
0024-4074
Volume/pages
163:4(2010), p. 447-472
ISI
000281135700003
Full text (Publisher's DOI)
Full text (publisher's version - intranet only)
UAntwerpen
Faculty/Department
Research group
Publication type
Subject
External links
Web of Science
Record
Identification
Creation 30.08.2010
Last edited 17.11.2017
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