Intercontinental Mediterranean disjunct mosses: morphological and molecular patterns.
ABSTRACT This study focused on three species that occur disjunctly between western North America and the Mediterranean region of southern Europe, northern Africa, and western Asia, forming the so-called Madrean-Tethyan distribution pattern. Quantitative morphological characters were measured in New and Old World plants to find any subtle phenotypic differentiation between the disjunct populations. Sequences from the nuclear ribosomal internal transcribed spacer region were obtained from the same populations to assess differentiation at the molecular level and to compare molecular diversity with patterns of morphological similarity among plants. Little or no morphological differentiation existed between New and Old World plants in any of the species, but internal transcribed spacer (ITS) sequences revealed some phylogeographic structure. Patterns of morphological similarity in all three species were incongruent with phylogeographic structure revealed by sequence data. New World populations were more variable than Old World populations at the molecular level in the three species. Despite some evidence for differentiation between disjunct plants, no plausible mutation rate would date the divergence at ≥20 million years ago (MYA), as implied by the Madrean-Tethyan hypothesis. Recent long-distance dispersal is a more likely explanation for intercontinental disjunctions in these species.
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ABSTRACT: The terricolous and saxicolous bryophytes of the Jbel Bouhalla (Rif Cordillera, Morocco) have been studied. This mountainous system, characterized by basic geology, contains the largest and best conserved forest of Abies pinsapo subsp. maroccana in Northern Africa. The catalogue is composed of 121 taxa, of which 108 are mosses and 13 liverworts. Of these, nine are new to the African continent (Acaulon mediterraneum, Claopodium whippleanum, Gymnostomum lanceolatum, Hedwigia stellata, Orthotrichum cupulatum var. baldacci, Schistidium brunnescens subsp. griseum, S. crassipilum, Scorpiurium sendtneri, Seligeria acutifolia), Eurhynchium schleicheri is new for mainland Africa, and seven are new records for Morocco (Barbula enderesii, Bryum dunense, Campyliadelphus chrysophyllus, Fissidens dubius, Hedwigia ciliata var. leucophaea, Pleuridium acuminatum, Pseudoleskeella catenulata).Journal of Bryology 08/2002; 24(3):243-250. · 1.35 Impact Factor
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ABSTRACT: Datisca (Datiscaceae) is a ditypic genus with an intercontinentally disjunct distribution. Chloroplast DNA restriction site data was obtained from 23 populations and four 10–20 year old herbarium specimens ofD. glomerata and three populations ofD. cannabina from throughout their geographic ranges in western North America and southwest-central Asia, respectively. InD. glomerata, plastome diversity is partitioned geographically. All populations from southern California have a common plastome, while most populations north of this region share a relatively divergent plastome (0.49% sequence divergence). Likewise, these plastomes are highly divergent (0.87% mean sequence divergence) from those found inD. cannabina. Biogeographic processes dating to the Pleistocene and Late Miocene may be responsible for these intra- and interspecific patterns of chloroplast DNA divergence.Plant Systematics and Evolution 01/1992; 181(1):121-132. · 1.31 Impact Factor
- American Journal of Botany - AMER J BOT. 01/1996; 83(3).