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Spiranthes romanzoffiana Cham. is restricted in Europe to the British Isles, where it is recognised as a conservation priority species due to frequent extirpation of populations along with no evidence of seed set; vegetative reproduction has been invoked as the sole means of perpetuation and dispersal. To investigate the reproductive ecology of this(More)
Epigenetic information includes heritable signals that modulate gene expression but are not encoded in the primary nucleotide sequence. We have studied natural epigenetic variation in three allotetraploid sibling orchid species (Dactylorhiza majalis s.str, D. traunsteineri s.l., and D. ebudensis) that differ radically in geography/ecology. The epigenetic(More)
A gynostemium, comprising stamen filaments adnate to a syncarpous style, occurs in only threc groups of monocots: the large family Orchidaceae (Asparagales) and two small genera Pauridia (Hypoxidaceae: Asparagales) and Corsia (Corsiaceae, probably in Liliales), all epigynous taxa. Pauridia has actinomorphic (polysymmetric) flowers, whereas those of Corsia(More)
BACKGROUND Hybridization and polyploidy are potent forces that have regularly stimulated plant evolution and adaptation. Dactylorhiza majalis s.s., D. traunsteineri s.l. and D. ebudensis are three allopolyploid species of a polyploid complex formed through unidirectional (and, in the first two cases, recurrent) hybridization between the widespread diploids(More)
Tribe Orchideae dominates the orchid flora of the temperate Northern Hemisphere but its representatives in East Asia had been subject to less intensive phylogenetic study than those in Eurasia and North America. Although this situation was improved recently by the molecular phylogenetic study of Jin et al., comparatively few species were analyzed from the(More)
Recent attempts to address the long-debated 'origin' of the angiosperms depend on a phylogenetic framework derived from a matrix of taxa versus characters; most assume that empirical rigour is proportional to the size of the matrix. Sequence-based genotypic approaches increase the number of characters (nucleotides and indels) in the matrix but are confined(More)
Recent phylogenetic reconstructions suggest that axially condensed flower-like structures evolved iteratively in seed plants from either simple or compound strobili. The simple-strobilus model of flower evolution, widely applied to the angiosperm flower, interprets the inflorescence as a compound strobilus. The conifer cone and the gnetalean 'flower' are(More)
Background and Aims. The Macaronesian islands represent an excellent crucible for exploring speciation. This dominantly phenotypic study complements a separate genotypic study, together designed to identify and circumscribe Platanthera species (butterfly-orchids) on the Azores, and to determine their geographic origin(s) and underlying speciation(More)
Background and Aims. The presence of novel structures in orchid flowers, including auricles, rostellum and bursicles on the gynostemium and a lobed labellum, has prompted long-standing homology disputes, fuelled by conflicting evidence from a wide range of sources. Re-assessment of this debate using an improved model is timely, following recent phylogenetic(More)