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This study focuses on the frequency of reproductive modes and the role of reproductive mode variation in diversification of the genus Sorbus s.l. and evolutionary success of individual taxa. Our sampling covers all four ploidies known in Sorbus and includes stabilized taxa and recently formed biotypes. We infer reproductive modes of 3660 seeds using the flow cytometric seed screen method; we also calculated ploidy of contributing pollen. Sorbus shows high variability in reproduction pathways (sexuality, apomixis, formation of BIII hybrids, haploid parthenogenesis). Diploids are sexual, whereas polyploids show predominantly pseudogamous apomixis. In half of the polyploids studied, several reproductive modes were present and even intra-individual variation was detected. Diploids, tetraploids and pentaploids are pollinated by conspecific pollen, whereas triploids are largely, but not fully, dependent on the pollen of other species. In pseudogamous seeds, fertilization of the central cell by both sperms is a dominant pathway of endosperm origin. Flow cytometry of pollen did not detect unreduced pollen at any ploidy. The principal mechanisms of diversification in Sorbus are residual sexuality in apomicts, production of triploid taxa from diploid–tetraploid crosses and production of BIII hybrids. Evolutionary success of Sorbus taxa is largely dependent on the breeding system and is determined by self-(in)compatibility and the interplay between stabilizing apomixis and variation-generating sexuality.

Hieracium cyathis (Ley) W. R. Linton (Asteraceae), Chalice Hawkweed, is a rare species endemic to Britain. It is a distinct member of Hieracium Section Oreadea, characterized by a short acladium and out-curved tips to the phyllaries. Historic records and current field survey indicate it has occurred in two localities in SW England and seven in South Wales. It is still present in all sites except for one Welsh locality, is significantly threatened at Cheddar Gorge, and two Welsh sites have only three plants each. Comparative morphology, cultivation experiments and amplified fragment length polymorphism (AFLP) analysis do not support the reported differences between material from SW England and Wales. AFLP analysis showed that every plant in the field was genetically similar but different, and minor genetic variation was found in one progeny array. It is a triploid (2n = 27) with apomictic seed production, and 26% potentially viable pollen. It qualifies as ‘Near Threatened’ under the 2001 IUCN threat criteria. General guidelines for conservation of microspecies of Hieracium are discussed. © 2008 The Linnean Society of London, Botanical Journal of the Linnean Society, 2008, 156, 669–680.

The parentage of polyploid Sorbus species in the British Isles was investigated using plastid DNA microsatellites. Four hundred and fifty-three samples from 30 taxa were screened using six microsatellite fragments, which gave 28 haplotypes. The haplotypes formed groups clearly related to the ancestral diploids Sorbus aria, Sorbus aucuparia, and Sorbus torminalis. Species in the Sorbus aria group all had Aria haplotypes (with the exception of one English S. aria), species in the Sorbus anglica group had an Aucuparia haplotype, and species in the Sorbus latifolia group had a Torminalis haplotype. Sorbus intermedia had an Aucuparia haplotype. This indicated that the hybridization events that led to the formation of species in the S. anglica and S. latifolia groups usually did so with S. aria s.l. as the pollen-donating (paternal) parent. The polyploids S. anglica, Sorbus bristoliensis, Sorbus croceocarpa, Sorbus decipiens, Sorbus devoniensis, Sorbus hibernica, Sorbus lancastriensis, Sorbus leptophylla, Sorbus leyana, Sorbus minima, Sorbus rupicola, Sorbus subcuneata, Sorbus vexans, Sorbus whiteana, Sorbus wilmottiana, and three unnamed taxa may each be derived from a single maternal lineage. The polyploids Sorbus eminens, Sorbus porrigentiformis, and S. latifolia have multiple maternal lineages. The two primary diploid hybrids S. × thuringiaca and S. × vagensis have arisen many times independently. © 2007 The Linnean Society of London, Botanical Journal of the Linnean Society, 2007, 154, 291–304.

The temporal and geographical variation in the history of botanical recording in the British Isles between 1836 and 1988 has been reconstructed from literature, herbarium, and field records, and related to the number and distribution of botanists. The number of botanists increased steadily to the 1930s and then five-fold after the Second World War, and is a consistent proportion of the local population. The amount of variation in the literature, assessed from the number of pages published, number of publications, and number of floras, has changed from a low rate between 1836 and 1880, to twice that between 1890 and 1940, and increased steadily to 1988. The number of herbarium specimens collected was also low up to the 1870s and then increased three-fold between 1870 and 1914, decreased between the World Wars, increased in the 1950s, and then decreased as conservation concerns came into play. The number of field records, now on computer, has risen dramatically since the 1930s, especially associated with major recording projects. The Botanical Society of the British Isles (BSBI) Monitoring Scheme data show a strong relationship between the number of hours spent recording at a site and the number of species recorded. The production of literature, collection of herbarium specimens, and field records also vary geographically, being concentrated in the areas in which botanists live. General patterns of recording activity are presented from a combination of the data that follow the general trends shown by the sources. There has been an increase in recording activity, with a low level between 1836 and 1870, followed by a large increase, peaking between 1890 and 1910, followed by decreases during the World Wars, with a recovery between, and a sustained increase since 1950. There is a clear trend from a high recording activity in south-east England to low levels in Scotland and, especially, Ireland, high levels being associated with the main population areas. Temporal and geographical variations in recording activity need to be taken into account when assessing floristic change. © 2006 The Linnean Society of London, Botanical Journal of the Linnean Society, 2006, 152, 303–330.

Botanical recording data are often used to assess changes in the frequencies of plant species over time, but are subject to marked variations in recording activity. We compare and evaluate some general methods that can be used to detect changes in species’ frequencies taking into account the recording variations. Models for 15 species that have been studied in detail previously were compared using the numbers of individual records, sites, hectads, or vicecounties at different time scales (year, decade, moving averages, and pre-/post- specific dates), with or without correction for recording variation. The best methods had a correction for the amount of recording over time, summarized records by decade or moving average, and used an extrapolation between first and last records for sites or hectads. Increasing the geographical and temporal scales can decrease the influence of recording variations, but leads to a loss of sensitivity and under-estimates the true extent of change. The choice between sites and hectads will depend on the detail of the records available; cruder data sets should use the latter. © 2006 The Linnean Society of London, Botanical Journal of the Linnean Society , 2006, 152 , 279‐301.

Asparagus prostratus Dumort(wild asparagus) and A. officinalis L. (cultivated asparagus), often regarded as subspecies or varieties of a single species, have been confused for historical and nomenclatural reasons. A taxonomic review was carried out, and they were found to be distinct species which differ in morphology (characters retained in cultivation), cytology, distribution and ecology, and they are reproductively isolated. The tetraploid A. prostratus is unlikely to be the taxon from which the diploid A. officinalis evolved. Morphological descriptions are presented, and A. prostratus is lectotypified. A. prostratus is a western European endemic of coasts of Belgium, Britain, the Channel Islands, France, Germany, Ireland, Spain and The Netherlands.