ABSTRACT
Species radiations should be facilitated by short generation times and limited dispersal among discontinuous populations. Hawaii's hyper-diverse, landscape-dominant tree, Metrosideros, is unique among the islands' radiations for its massive populations that occur continuously over space and time within islands, its exceptional capacity for gene flow by both pollen and seed, and its extended life span (ca. >650 years). Metrosideros shows the greatest phenotypic and microsatellite DNA diversity on O'ahu, where taxa occur in tight sympatry or parapatry in mesic and montane wet forest on 2 volcanoes. We document the nonrandom distributions of 12 taxa (including unnamed morphotypes) along elevation gradients, measure phenotypes of ~6-year-old common-garden plants of 8 taxa to verify heritability of phenotypes, and examine genotypes of 476 wild adults at 9 microsatellite loci to compare the strengths of isolation across taxa, volcanoes, and distance. All 8 taxa retained their diagnostic phenotypes in the common garden. Populations were isolated by taxon to a range of degrees (pairwise FST between taxa: 0.004-0.267), and there was no pattern of isolation by distance or by elevation; however, significant isolation between volcanoes was observed within monotypic species, suggesting limited gene flow between volcanoes. Among the infraspecific taxa of Metrosideros polymorpha, genetic diversity and isolation significantly decreased and increased, respectively, with elevation. Overall, 5 of the 6 most isolated taxa were associated with highest elevations or otherwise extreme environments. These findings suggest a principal role for selection in the origin and maintenance of the exceptional diversity that occurs within continuous Metrosideros stands on O'ahu.
Subject(s)
Genetic Speciation , Myrtaceae/genetics , Reproductive Isolation , Ecosystem , Extreme Environments , Hawaii , Phylogeography , Plant Dispersal , Trees/geneticsABSTRACT
Diplachne P. Beauv. comprises two species with C4 (NAD-ME) photosynthesis. Diplachne fusca has a nearly pantropical-pantemperate distribution with four subspecies: D. fusca subsp. fusca is Paleotropical with native distributions in Africa, southern Asia and Australia; the widespread Australian endemic D. f. subsp. muelleri; and D. f. subsp. fascicularis and D. f. subsp. uninervia occurring in the New World. Diplachne gigantea is known from a few widely scattered, older collections in east-central and southern Africa, and although Data Deficient clearly is of conservation concern. A discussion of previous taxonomic treatments is provided, including molecular data supporting Diplachne in its newer, restricted sense. Many populations of Diplachne fusca are highly tolerant of saline substrates and most prefer seasonally moist to saturated soils, often in disturbed areas. Some populations of Diplachne fusca in southern Asia combine nitrogen-fixation, high salinity tolerance and palatibilty to livestock, which should be pursued with further research for purposes of soil reclamation. Diplachne fusca subsp. uninervia is the most invasive of the subspecies and is becoming weedy in some non-native areas, including in the Old World. This monograph provides detailed descriptions of all taxa, a key to the species and subspecies, geographic distributions and information on the anatomy of leaves, stems, lemmatal micromorphology and discussions of the chromosome numbers. Lectotypes are designated for: Atropis carinata Grisb.; Diplachne acuminata Nash; Diplachne capensis (Nees) Nees var. concinna Nees; Diplachne capensis (Nees) Nees var. obscura Nees, Diplachne capensis (Nees) Nees var. prolifera subvar. minor Nees, Diplachne halei Nash, Diplachne maritima E.P. Bicknel, Diplachne muelleri Benth., Diplachne reverchonii Vasey, Diplachne tectoneticola Backer, Leptochloa imbricata Thurb., Leptochloa neuroglossa Peter, Leptochloa uninervia var. typica fo. abbreviata Parodi, Triodia ambigua R. Br. and Triodia parviflora R. Br.
ABSTRACT
Seventeen new endemic species of the genus Eugenia L. (Myrtaceae) are proposed from Madagascar, including: Eugeniaandapae N. Snow, Eugeniabarriei N. Snow, Eugeniabemangidiensis N. Snow, Eugeniacalciscopulorum N. Snow, Eugeniadelicatissima N. Snow, Callm. & Phillipson, Eugeniaechinulata N. Snow, Eugeniagandhii N. Snow, Eugeniahazonjia N. Snow, Eugeniaiantarensis N. Snow, Eugeniamalcomberi N. Snow, Eugeniamanomboensis N. Snow, Eugeniaobovatifolia N. Snow, Eugeniaranomafana N. Snow & D. Turk, Eugeniaravelonarivoi N. Snow & Callm., Eugeniarazakamalalae N. Snow & Callm., Eugeniatiampoka N. Snow & Callm., and Eugeniawilsoniana N. Snow, and one new combination, Eugeniarichardii (Blume) N. Snow, Callm. & Phillipson is provided. Detailed descriptions, information on distribution and ecology, distribution maps, vernacular names (where known), digital images of types, comparisons to morphologically similar species. Preliminary assessment of IUCN risk of extinction and conservation recommendations are provided, including Vulnerable (4 species), Endangered (2 species), and Critically Endangered (4 species). Lectotpyes are designated for Eugeniahovarum H. Perrier, Eugenianompa H. Perrier, and Eugeniascottii H. Perrier respectively.
RésuméDix-sept nouvelles espèces endémiques du genre Eugenia L. (Myrtaceae) sont proposées pour Madagascar, incluant Eugeniaandapae N. Snow, Eugeniabarriei N. Snow, Eugeniabemangidiensis N. Snow, Eugeniacalciscopulorum N. Snow, Eugeniadelicatissima N. Snow, Callm. & Phillipson, Eugeniaechinulata N. Snow, Eugeniagandhii N. Snow, Eugeniahazonjia N. Snow, Eugeniaiantarensis N. Snow, Eugeniamalcomberi N. Snow, Eugeniamanomboensis N. Snow, Eugeniaobovatifolia N. Snow, Eugeniaranomafana N. Snow & D. Turk, Eugeniaravelonarivoi N. Snow & Callm., Eugeniarazakamalalae N. Snow & Callm., Eugeniatiampoka N. Snow & Callm., et Eugeniawilsoniana N. Snow, ainsi qu'une nouvelle combination, Eugeniarichardii (Blume) N. Snow, Callm. & Phillipson. Des descriptions détaillées, des informations sur la distribution et l'écologie, des cartes de distribution, des noms vernaculaires (quand ils sont connus), des images digitalisées des types, des comparaisons avec les espèces morphologiquemnet proches et une évaluation préliminaire du risque d'extinction selon l'UICN ainsi que des recommendations de conservation sont fournies. Des lectotypes sont désignés pour Eugeniahovarum H. Perrier, Eugenianompa H. Perrier et Eugeniascottii H. Perrier.
ABSTRACT
Disakisperma Steud. is a genus of four predominantly perennial C4 (NAD-ME) species in the Americas, Africa, and Asia. Its species previously were treated in Eleusine, Eragrostis, Coelachyrum, Cypholepis, Leptochloa, or Diplachne by nearly all authors.It includes the widespread North and South American amphitropical disjunct Disakisperma dubium (type of the genus), Disakisperma eleusine from southern Africa, Disakisperma obtusiflorum from central and northern Africa to southern Asia, and Disakisperma yemenicum, comb. nov. from eastern and southern Africa to Yemen. This paper provides a key to the species, geographic distributions, descriptions, including comments on the anatomy of leaves, stems, lemmatal micromorphology, a phylogram based on five molecular markers, and discussions of chromosome numbers. The species are rarely, if at all, known outside of their native ranges and are unlikely to become aggressively invasive. All species are considered Least Concern following IUCN guidelines. Lectotypes are designated for Diplachne dubia var. pringleana Kuntze, Disakisperma mexicana Steud., Eragrostis yemenica Schweinf., and Leptochloa appletonii Stapf.
ResumenDisakisperma Steud. es un género de quatro especies perennes C4 (NAD-ME), las cuales que son de las Américas y África y Asia. Sus especies previamente fueron tratados en Eleusine, Eragrostis, Coelachyrum, Cypholepis, Leptochloa, o Diplachne por casi todos los autores. Incluye la generalizada del Norte y América del Sur amfitropical disjunta Disakisperma dubium (tipo del género), Disakisperma eleusine desde el sur de África, Disakisperma obtusiflorum del centro y el norte de África hasta el sur de Asia, y Disakisperma yemenicum, comb. nov. del este y sur África a Yemen. Este documento proporciona una clave para las especies y las descripciones completas, incluidos los comentarios sobre la anatomía de las hojas, tallos, micromorfología lemmatal, una filograma basado en cinco marcadores moleculares y las discusiones de los números de cromosomas. Las especies son raramente, si acaso, conocida fuera de sus áreas de distribución natural y es poco probable para convertirse en invasora agresiva. Todos las epecies se consideran la designación de Least Concern sigue IUCN. Se designa lectotipos para Diplachne dubia var. pringleana Kuntze, Disakisperma mexicana Steud., Eragrostis yemenica Schweinf. y Leptochloa appletonii Stapf.
ABSTRACT
A systematic treatment including descriptions and a key for identification is provided for the two species of Trigonochloa, a genus recently segregated from the polyphyletic Leptochloa s.l. Trigonochloa ranges from southern Africa east to India and Sri Lanka, reflecting the widely ranging Trigonochloa uniflora. Trigonochloa rupestris has a more limited distribution from East Africa to Yemen. Trigonochloa is diagnosable from other chloridoid grasses based on its unusually flaccid and membranous leaves that have uniquely enlarged lateral cells in the parenchyma sheath surrounding the vascular bundles in Trigonochloa uniflora (unconfirmed for Trigonochloa rupestris given limited material), primary and secondary vascular bundles that do not project above or below in fresh material, XyMS+ leaf anatomy, narrow spicate primary inflorescence branches, spikelets with one (or rarely two) florets, thinly membranous to hyaline lemmas, and a trigonous caryopses that bear a narrow but deep sulcus on the hilar side. Lectotypes are designated for Agrostis montana and Cynodon gracilis. The synonym Leptochloa laurentii De Wild. is confirmed for Trigonochloa uniflora.
ABSTRACT
BACKGROUND AND AIMS: Leptochloa (including Diplachne) sensu lato (s.l.) comprises a diverse assemblage of C(4) (NAD-ME and PCK) grasses with approx. 32 annual or perennial species. Evolutionary relationships and a modern classification of Leptochloa spp. based on the study of molecular characters have only been superficially investigated in four species. The goals of this study were to reconstruct the evolutionary history of Leptochloa s.l. with molecular data and broad taxon sampling. METHODS: A phylogenetic analysis was conducted of 130 species (mostly Chloridoideae), of which 22 are placed in Leptochloa, using five plastid (rpL32-trn-L, ndhA intron, rps16 intron, rps16-trnK and ccsA) and the nuclear ITS 1 and 2 (ribosomal internal transcribed spacer regions) to infer evolutionary relationships and revise the classification. KEY RESULTS: Leptochloa s.l. is polyphyletic and strong support was found for five lineages. Embedded within the Leptochloa sensu stricto (s.s.) clade are two Trichloris spp. and embedded in Dinebra are Drake-brockmania and 19 Leptochloa spp. CONCLUSIONS: The molecular results support the dissolution of Leptochloa s.l. into the following five genera: Dinebra with 23 species, Diplachne with two species, Disakisperma with three species, Leptochloa s.s. with five species and a new genus, Trigonochloa, with two species.
Subject(s)
Phylogeny , Poaceae/genetics , Base Sequence , DNA Primers , Evolution, Molecular , Introns , Plastids , Poaceae/classificationABSTRACT
Five new species of Rhodamnia are proposed for New Guinea, including Rhodamnia asekiensis, Rhodamnia daymanensis, Rhodamnia makumak, Rhodamnia taratot, and Rhodamnia waigeoensis. Rhodamnia sharpeana, known previously only in Australia, is reported for the first time for Papua New Guinea. Detailed species descriptions and associated taxonomic data are provided for all species. A key is provided for species of Rhodamnia with stellate trichomes. Given the overall paucity of collections, all species are tentatively assigned as Data Deficient following IUCN conservation recommendations.
