Tribal delimitation and phylogenetic relationships of Loteae and Coronilleae (Faboideae: Fabaceae) with special reference to Lotus: evidence from nuclear ribosomal ITS sequences

The temperate herbaceous tribes Loteae and Coronilleae have traditionally been regarded as taxonomically distinct entities. More recent morphological assessments, however, have challenged this view and suggest combining the two tribes under Loteae. Two key features used to distinguish the Coronilleae from Loteae include jointed fruits and branched root nodules. We evaluate the taxonomic utility of these characters using information derived from phylogenetic analyses of the internal transcribed spacers ITS1 + 2, and the intervening 5.8S region of nuclear ribosomal DNA. Results from this study show that neither the Loteae nor Coronilleae form individual monophyletic groups, and that key fruit and root nodule characters used to distinguish the Coronilleae are homoplastic. Given these data, we support the recognition of a single tribe, Loteae. We also find that Lotus, the largest and most morphologically complex genus in either tribe, is not monophyletic. Rather, it consists of two geographically distinct lineages, Old and New World, each of which are more closely related to other Loteae genera: Old World Lotus are more closely related to Old World Anthyllis, while New World Lotus show closer affinities to Old World Coronilla. These data also have important implications for the biogeography of New World Lotus: equally most parsimonious reconstructions suggest a complex scenario of intercontinental dispersals that involve not only Old World Lotus but Coronilla as well.     

The origin of bird pollination in Macaronesian Lotus (Loteae, Leguminosae)

The four red-flowered, apparently bird-pollinated Lotus species from the Canary Islands have previously been classified in their own genus, Rhyncholotus. Currently, they are considered as a separate section within genus Lotus, distinct from other herbaceous Canarian congeners which are yellow-flowered and bee-pollinated. A combined analysis of four nuclear regions (including ITS and three homologues of CYCLOIDEA) and three plastid regions (CYB6, matK and trnH-psbA) nests the four bird-pollinated species within a single extant species of bee-pollinated Lotus (L. sessilifolius), in a very extreme example of species paraphyly. Therefore, our data compellingly support the hypothesis that the Macaronesian Lotus species with a bird pollination syndrome are recently derived from entomophilous ancestors. Calibration of the phylogenetic trees using geological age estimates of the most recent islands (La Palma and El Hierro) together with oldest ages of Fuerteventura indicates that bird pollination evolved ca. 1.7 Ma in the Canarian Lotus. These four bird-pollinated species share a most recent common ancestor (MRCA) with L. sessilifolius that dates to about 2.2 Ma. Our analyses further suggest that the evolution of the bird pollination syndrome was likely triggered by the availability of new niches in La Palma and Tenerife as a result of recent volcanic activity.     

A Cladistic Analysis of the New World Species of Lotus L. (Fabaceae, Loteae)

The genus Lotus L. is a monophyletic group diagnosed by the possession of a standard claw with thickened infolded margin, stamens diadelphous, and the style hardened from the base. It comprises approximately 200 species distributed throughout the world. A cladistic analysis of the New World species was performed using 39 morphological and anatomical characters (29 from seed morphology and anatomy, 1 from plant habit, 1 from leaf morphology, 6 from flower morphology, and 2 from fruit morphology). Dorycnium, Edentolotus, Krokeria , and Pedrosia , of the Old World, and 28 species of the New World were considered terminal taxa. Tetragonolobus Scop. was chosen to root the cladograms and Dorycnium Mill. to reroot them. With Tetragonolobus the analysis yielded 15 equally parsimonious trees, each with a length of 74 steps, a consistency index of 0.62, and a retention index of 0.89. The 15 initial trees and the strict consensus tree defined 12 monophyletic groups. All terminal taxa form a monophyletic group diagnosed by the presence of a radicular lobe discernible to conspicuous (character 10); rim aril thick (character 13); stipules absent (character 31); and style simple and nondilated (character 36). The New World species form a monophyletic group on the basis of the seed relationship of length to width in hilar view 1.5:1 to 2:1 (character 5); micropyle linear-deltoid to bifurcate (character 19); and keel erostrate (character 33). Identical monophyletic groups were obtained when Dorycnium was used as root. These results are discussed in the context of data on cytology and morphology.     

Population genetic differentiation in taxa of Lotus (Fabaceae: Loteae) endemic to the Gran Canarian pine forest

A survey of allozyme variation at 17 loci in 14 populations representing four taxonomically problematic Gran Canarian pine forest endemic taxa of Lotus (L. genistoides, L. holosericeus, L. spartioides and some taxonomically uncertain populations collected under the designation Lotus sp.) was conducted to examine their diversification and systematic relationships. All groups exhibited high values of genetic variation, although inbreeding was common within populations. Considerable among-population genetic homogeneity was detected, as inferred from low values of Gst within each of the groups. The high population sizes of these taxa and a lack of evidence for isolation by distance or genetic bottlenecks indicate that diversity has accumulated over a long period of environmental stability. The association of high genetic distances with low linear distances, and the substantial increase in the values of Gst when the taxa considered were merged in different combinations hint at an incipient (yet probably taxonomically insufficient) reproductive isolation. The genetic similarity between L. genistoides, L. holosericeus and L. spartioides, together with the different behaviour of the populations collected under the designation Lotus sp., may have important implications for the restructuring of the taxonomy of this group when the ongoing morphological studies are completed.     

Molecular and morphological evidence for hybridization between endemic Canary Island Convolvulus

Morphological data and molecular data from the chloroplast trn H- psb A region and nuclear ribosomal ITS region are used to test the hypothesis that the problematic Canary Island endemic Convolvulus floridus var. virgatus is a hybrid between the endemic species C. floridus and C. scoparius . Analysis of mean leaf length and width of 58 individuals indicates that accessions referable to C. floridus var. virgatus are intermediate between the parental taxa in leaf dimensions. Direct sequencing of the ITS region of C. scoparius and C. floridus revealed two species-specific ribotypes distinguished by 10 base differences. Examination of ITS chromatograms for putative hybrids revealed polymorphisms at those sites that are diagnostic between species in all except one putative hybrid. Morphological intermediacy and ITS additivity therefore support the hybrid status of C. floridus var. virgatus . An analysis of intraindividual ITS variation confirmed the co-occurrence of both parental ribotypes in putative hybrids and demonstrated that some hybrid individuals contained chimaeric ITS types. It is proposed that chimaeric ITS types are the result of recombination following backcrossing. Sequencing of the trn H- psb A region revealed four haplotypes. Three were, for the most part, confined to C. floridus and putative hybrids although one C. scoparius accession was also found to share this haplotype. The remaining haploype was only found in C. scoparius and putative hybrid accessions. Patterns of haplotype distribution between parental and hybrid accessions suggest multiple, bidirectional hybridization events between C. floridus and C. scoparius . The nomenclature of the hybrid is discussed and the necessary new name C.  ×  despreauxii is proposed.  © 2007 The Linnean Society of London, Botanical Journal of the Linnean Society , 2007, 154 , 187–204.     

Molecular phylogenetic evidence for the origin of a diploid hybrid of Paeonia (Paeoniaceae)

There is growing evidence that hybridization not only by means of allopolyploidy but also at the homoploidy level was a major driving force of plant diversification. While allopolyploidy is known to be a common mode of speciation in Paeonia (Paeoniaceae), hybrid speciation at the diploid level needs further evaluation. Paeonia anomala was previously considered to be an interspecific hybrid but with an unknown ploidy level. In this study P. anomala is identified as a diploid (2n = 10). With increased sampling of populations and molecular markers, we showed that P. anomala is a homoploid hybrid that originated from a cross between P. veitchii and P. lactiflora. Five populations of P. anomala were sequenced for the following molecular markers: the matK gene and two intergenic spacers, psbA-trnH and rps16-trnQ, of the chloroplast genome; the internal transcribed spacers (ITS) of nuclear ribosomal DNA; and three low-copy nuclear genes, Adh1, Adh2, and Gpat. The populations of P. anomala were grouped together with P. veitchii on the ITS and Gpat phylogenies but with P. lactiflora on the chloroplast phylogeny. Sequence polymorphism was found at the Adh1 and Adh2 loci within individuals of P. anomala. These polymorphic sequences were grouped with P. veitchii and P. lactiflora, respectively. Phenetic analysis indicated that P. anomala is morphologically similar to P. veitchii. Phenotypic evolution resulting from the combination of two diverged genomes might have occurred primarily at the physiological level and allowed P. anomala to adapt to geographic regions different from those of its parents.     

Evaluation of hypotheses concerning the origin of Lotus corniculatus (Fabaceae) using isoenzyme data

Summary An isoenzyme survey was conducted for several geographically dispersed accessions of four diploid Lotus species, L. alpinus Schleich., L. japonicus (Regel) Larsen, L. tenuis Waldst. et Kit and L. uliginosus Schkuhr, and for the tetraploid L. corniculatus L., in order to ascertain whether isoenzyme data could offer additional evidence concerning the origin of L. corniculatus. Seven enzyme systems were examined using horizontal starch gel electrophoresis. These were PGI, TPI, MDH, IDH, PGM, 6-PGDH, and ME. Lotus uliginosus had monomorphic unique alleles, that were not found within L. corniculatus, at 7 loci. These loci and alleles are: Tpi1-112, Pgm1,2-110, Pgm3-82, Mdh3-68, 6-Pgdh1-110, 6-Pgdh2-98,95, and Me2-100. Other diploid taxa contained alleles found in L. corniculatus for these and other loci. The implications of the isoenzyme data to theories on the origin of L. corniculatus are discussed.Communicated by H. F. Linskens     

A New Species of Coronilla (Loteae, Fabaceae) from Southeastern Spain: Evidence from Morphological and Molecular Data

Currently, there are nine species classified within the genus Coronilla (Loteae, Fabaceae); however, some populations discovered in the province of Almería, SE Spain, have features that are not present, as a whole, in the other known species. These plants are related to Coronilla juncea and C. minima, although several features of branches, leaves, flowers and seeds (zigzag branches; fleshy, deciduous leaves without hyaline margin; connate reddish stipules; very narrow seeds with fluted foveolae) are usually recognized as belonging to distinct species. To clarify the taxonomic status of these populations, morphological and genetic studies have been performed. The results obtained suggest that their separate classification is appropriate. Accordingly, a new species, Coronilla talaverae, whose currently recorded range is restricted to three populations in southeastern Spain is described here. Regarding its risk of extinction, the IUCN red list criteria have been followed to assess its category, proposing the status EN B1ab(i,ii,iii,v)+2ab(i,ii,iii,v). In addition, an identification key is provided for the species of the genus Coronilla.     

Chloroplast-DNA variation in the genus Lotus (Fabaceae) and further evidence regarding the maternal parentage of Lotus corniculatus L.

 To resolve the maternal parentage of the tetraploid Lotus corniculatus, restriction-site variation of chloroplast DNA (cpDNA) was studied in several accessions of that species, in the four putative parental diploid species, L. tenuis, L. alpinus, L. japonicus and L. uliginosus, and in four phylogenetically more distant diploid species, L. hispidus, L. edulis, L. ornithopodoides and Tetragonolobus maritimus var. siliquosus. Evidence of cpDNA maternal inheritance was obtained by using reciprocal controlled crosses between plants of L. corniculatus and natural tetraploid individuals of L. alpinus showing very distinct restriction patterns. Interspecific cpDNA variation in the eight Lotus species and T. siliquosus was analysed by comparing cpDNA fragment patterns produced by five restriction endonucleases and totalling 304 distinct fragments. Genetic differentiation in cpDNA was very high between the L. corniculatus group and L. hispidus on the one hand, and the three other species on the other hand. Sixteen restriction-site mutations and eight length polymorphisms were identified among the five species of the L. corniculatus group and L. hispidus, Lotus uliginosus, L. alpinus and L. japonicus showed at least six DNA changes with regard to the molecule of L. corniculatus. Accordingly, these species should be excluded as maternal progenitors of L. corniculatus. Conversely, the cpDNA of L. tenuis differed from that of L. corniculatus by only two small-length mutations. As also suggested previously from an analysis of several nuclear markers, the results reported here show decisively that L. tenuis may be considered as the most probable maternal ancestor of L. corniculatus. Received: 23 February 1997/Accepted: 28 February 1997     

Molecular phylogenetic evidence for the monophyly of Fritillaria and Lilium (Liliaceae; Liliales) and the infrageneric classification of Fritillaria

We present phylogenetic analyses of 37 taxa of Fritillaria (Liliaceae), 15 species of Lilium, and several outgroup taxa from Liliaceae s.s. to investigate the generic delimitation of Fritillaria in relation to Lilium as well as infrageneric relationships within Fritillaria. We used DNA sequences from the maturase-coding plastid matK gene and the trnK intron, the intron of the ribosomal protein-coding rpl16 plastid gene, and the nuclear ribosomal internal transcribed spacers (ITS). Phylogenetic analysis using maximum parsimony defined Fritillaria and Lilium (the latter including Nomocharis) as sister taxa. Fritillaria sections Fritillaria and Liliorhiza are supported in part, and some of the most enigmatic species usually included in Fritillaria (sections Petilium and Theresia and the monotypic genus Korolkowia) are closely related. The results support the new classification of Fritillaria proposed by Rix. We postulate independent origins of the underground bulbils found in Fritillaria davidii and the remainder of subgenus Liliorhiza.     

Molecular cytogenetic characterisation and phylogenetic analysis of the seven cultivated Vigna species (Fabaceae)

The genomic organisation of the seven cultivated Vigna species, V. unguiculata, V. subterranea, V. angularis, V. umbellata, V. radiata, V. mungo and V. aconitifolia, was determined using sequential combined PI and DAPI (CPD) staining and dual‐colour fluorescence in situ hybridisation (FISH) with 5S and 45S rDNA probes. For phylogenetic analyses, comparative genomic in situ hybridisation (cGISH) onto somatic chromosomes and sequence analysis of the internal transcribed spacer (ITS) of 45S rDNA were used. Quantitative karyotypes were established using chromosome measurements, fluorochrome bands and rDNA FISH signals. All species had symmetrical karyotypes composed of only metacentric or metacentric and submetacentric chromosomes. Distinct heterochromatin differentiation was revealed by CPD staining and DAPI counterstaining after FISH. The rDNA sites among all species differed in their number, location and size. cGISH of V. umbellata genomic DNA to the chromosomes of all species produced strong signals in all centromeric regions of V. umbellata and V. angularis, weak signals in all pericentromeric regions of V. aconitifolia, and CPD‐banded proximal regions of V. mungo var. mungo. Molecular phylogenetic trees showed that V. angularis and V. umbellata were the closest relatives, and V. mungo and V. aconitifolia were relatively closely related; these species formed a group that was separated from another group comprising V. radiata, V. unguiculata ssp. sesquipedalis and V. subterranea. This result was consistent with the phylogenetic relationships inferred from the heterochromatin and cGISH patterns; thus, fluorochrome banding and cGISH are efficient tools for the phylogenetic analysis of Vigna species.     

Astragalus (Fabaceae): A molecular phylogenetic perspective

Nucleotide sequences of the plastidmatK gene and nuclear rDNA internal transcribed spacer region were sampled fromAstragalus L. (Fabaceae), and its closest relatives within tribe Galegeae, to infer phylogenetic relationships and estimate ages of diversification. Consistent with previous studies that emphasized sampling for nrDNA ITS primarily within either New World or Old World species groups,Astragalus, with the exception of a few morphologically distinct species, is strongly supported as monophyletic based on maximum parsimony and Bayesian analyses ofmatK sequences as well as a combined sequence dataset. ThematK data provides better resolution and stronger clade support for relationships amongAstragalus and traditionally related genera than nrDNA ITS.Astragalus sensu stricto plus the genusOxytropis are strongly supported as sister to a clade composed of strictly Old World (African, Australasian) genera such asColutea. Sutherlandia, Lessertia, Swainsona, andCarmichaelia, plus several morphologically distinct segregates of EurasianAstragalus. Ages of these clades and rates of nucleotide substitution estimated from a fossil-constrained, rate-smoothed, Bayesian analysis ofmatK sequences sampled from Hologalegina indicateAstragalus diverged from its sister group,Oxtropis, 12–16 Ma, with divergence of Neo-Astragalus beginning ca 4.4. Ma. Estimates of absolute rates of nucleotide substitution forAstragalus and sister groups, which range from 8.9 to 10.2×10⁻¹⁰ substitutions per site per year, are not unusual when compared to those estimated for other, mainly temperate groups of papilionoid legumes. The results of previously published work and other recent developments on the phylogenetic relationships and diversification ofAstragalus are reviewed.     

An isoenzyme study in the genus Lotus (Fabaceae)

Summary Segregation of the cytosolic Pgi2 locus was studied among progeny of the synthetic allotetraploid (L. japonicus × L. alpinus)², the synthetic autotetraploid (L. alpinus)², and the cultivated tetraploid species L. corniculatus L. Evidence of an original diploid duplication found within the interspecific hybrid L. japonicus × L. alpinus was also found within the synthetic allotetraploid (quadruplication of loci). Evidence suggesting quadruplication of loci was also found in the tetraploid L. corniculatus, but not in the synthetic autotetraploid (L. alpinus)². It is suggested that the original duplication resulted from unequal crossing-over between homoeologues and that it provides evidence that L. corniculatus is a segmental allotetraploid. Quadruplication of loci in L. corniculatus could explain previously reported distorted tetrasomic ratios for segregation of qualitative characters in this species.     

Molecular Evidence for the Hybrid Origin of Bauhinia blakeana （Caesalpinioideae）

Bauhinia blakeana Dunn is the Hong Kong Special Administrative Region emblem and a popular horticultural species in many Asian countries. It was first described as a new species from Hong Kong almost a century ago. This plant is sterile and has long been considered a hybrid, possibly from two related species, B. purpurea and B. variegata. However, not much evidence based on molecular methods was available to support this hypothesis. In this study, sequences of internal transcribed spacer I （ITS1）, rbcL and atpB-rbcL intergenic spacer for five Bauhinia species and two varieties of one of the species were determined and compared. There were two types of ITS1 sequences in B. blakeana, one indistinguishable from that of B. purpurea and the other one identical to that of B. variegata. This confirmed that B. blakeana was a hybrid of these two species. Chloroplast atpB-rbcL intergenic spacer sequence of B. blakeana was identical to that of B. purpurea, indicating that B. purpurea was the female parent. The hybridization event seemed to occur only recently and was a rare incident. Its occurrence was likely facilitated by interspecific pollen competition. It appeared that human efforts played a crucial role in the preservation and ubiquity of B. blakeana.     

Molecular evidence for phylogenetic relationships among buntings and American sparrows (Emberizidae)

To help clarify controversial phylogenetic relationships within the family Emberizidae, we sequenced 1238 bp of mitochondrial DNA from the cytochrome b gene and a flanking portion of ND5. Although the longspurs ( Calcarius ) and the snow buntings ( Plectrophenax ) have been grouped with the Old World buntings ( Emberiza ) in traditional classifications, our molecular phylogenies constructed with maximum likelihood and maximum parsimony place these genera basal to a clade in which the Old World buntings and North American sparrows are sister groups. Contrary to the hypothesis that the radiation within Emberiza is recent following a westward expansion of emberizid stock into Eurasia from North America, we found that the level of genetic divergence among Old World buntings approximates those among different genera in North American sparrows. Thus the radiation of the Emberizidae seems to have occurred at roughly the same time in the Palaearctic and Nearctic. Our results are consistent with earlier analyses of allozymes, but sequences from multiple genes and new morphological analyses are required to fully resolve phylogenetic relationships within the Emberizidae.     

Molecular evidence for the hybrid origin of a new endemic species of Stylosanthes Sw. (Fabaceae) from the Mexican Yucatán Peninsula

Stylosanthes aff. calcicola is a formally undescribed tetraploid species from the Mexican Yucatán Peninsula, showing morphological similarities to the diploid species S. calcicola , but distinct in a number of characters. We used uni- and biparentally inherited molecular markers to infer the hybrid origin of this species in relation to known diploid species of Stylosanthes . Molecular characterization was based on length and/or DNA sequence variation of nuclear sequence-tagged site (STS) markers, the internal transcribed spacer (ITS) region of nuclear rDNA and the trnL intron of chloroplast DNA (cpDNA). Stylosanthes aff. calcicola contains a distinct cpDNA haplotype and nuclear DNA fragment, with closest relationship to the diploid species S. calcicola . In contrast, the DNA sequences of two nuclear loci reveal a closer relationship to the diploid species S. angustifolia , S. hispida , S. humilis , S. leiocarpa and S. viscosa . The majority of the STS markers showed additivity of PCR fragments in S. aff. calcicola , representing the combination of two genetically different genomes. We postulate that S. aff. calcicola is a distinct species of allotetraploid origin that appears to have originated once from hybridization between two divergent genomes, of which the maternal and paternal parent are closely related to, or derived from, a member of the lineages represented by S. calcicola and S. viscosa , respectively.  © 2002 The Linnean Society of London, Botanical Journal of the Linnean Society , 140 , 1–13.     

Molecular identification and characterization of wine yeasts isolated from Tenerife (Canary Island, Spain)

AIMS: The present study was aimed at the identification, differentiation and characterization of indigenous yeasts isolated from Tenerife vineyards (viticulture region that has never been characterized before). Microbiota were studied from 14 samples taken during fermentations carried out in the 2002 vintage, from 11 wineries belonging to five wine regions on Tenerife Island. METHODS AND RESULTS: Yeasts' strains were identified and characterized through restriction analysis of the 5.8S-internal transcribed spacer region and the mitochondrial DNA. At the beginning of alcoholic fermentation, 26 yeast species were found, where 14 species were present in significant frequencies in only one sample. Likewise, the Saccharomyces cerevisiae strains isolated are very specific, as they were only present in one wine region. CONCLUSIONS: There were isolated specific yeasts from each region on Tenerife Island. The founded yeasts may be responsible for distinctive and interesting properties of the studied wines. SIGNIFICANCE AND IMPACT OF THE STUDY: This study forms part of an extensive taxonomic survey within the ecological framework of vineyards in Tenerife. This investigation is an essential step towards the preservation and exploitation of the hidden oenological potential of the untapped wealth of yeast biodiversity in the grape growing regions of this island. The results obtained demonstrate the value of using molecular genetic methods in taxonomic and ecological surveys. The results also shed some light on the ecology and oenological potential of S. cerevisiae strains isolated from this unique environment.     

Molecular phylogenetic analyses reveal three new Ceratocystis species and provide evidence for geographic differentiation of the genus in Africa

The emergence of wattle wilt disease on non-native Acacia mearnsii trees in Africa, caused by the indigenous fungus Ceratocystis albifundus, has highlighted a need to better understand the diversity, ecology and distribution of Ceratocystis species in natural African environments. In this study we applied phylogenetic inference to identify and characterize isolates of Ceratocystis collected in a natural savanna ecosystem in South Africa. Three new species were recognized and are described as C. cryptoformis sp. nov. in the C. moniliformis complex, as well as C. thulamelensis sp. nov. and C. zambeziensis sp. nov., both residing in the C. fimbriata complex. Incorporating the new species into global phylogenies of Ceratocystis provided insights into the patterns of evolution and biogeography of this group of fungi. Notably, the African continent was identified as an important centre of diversification of Ceratocystis spp., from which several lineages of these fungi were shown to have radiated.     

Nonlocal transplantation and outbreeding depression in the subshrub Lotus scoparius (Fabaceae)

The genetic background of transplants used to create or augment wild populations may affect the long-term success of restored populations. If seed sources are from differently adapted populations, then the relative performance of progeny from crosses among populations may decrease with an increase in genetic differences of parents and in the differences of parental environments to the transplant location. We evaluated the potential for such outbreeding depression by hybridizing individuals from six different populations of Lotus scoparius var. scoparius and L. s. var. brevialatus. We used allozyme data to calculate genetic distances between source populations, and compiled climatic data and measured soil traits to estimate environmental distances between source populations. We found significant outbreeding depression following controlled crosses. In the greenhouse, the success of crosses (seeds/flower × seedlings/seed) decreased with increasing genetic distance between populations revealing genetically based outbreeding depression unrelated to local adaptation. After outplanting to one native site (in situ common garden), field cumulative fitness of progeny (survival × fruit production) decreased significantly with mean environmental distance of the parental populations to the transplant site, but not with genetic distance between the crossed populations. This result is consistent with a disruption of local adaptation. At the second, ecologically contrasting common garden, where low survival reduced statistical power, field cumulative fitness (survival × progeny height) did not decrease significantly with either environmental distance or genetic distance. Overall, intervariety crosses were 40 and 50% as fit (seeds/flower × seedlings/seed × survival × fruits at the first garden or × height at the second) as intravariety crosses. These results suggest that the cumulative outbreeding depression was caused by a combination of genetically based ecological differences among populations and other genomic coadaptation. We conclude that mixing genetically differentiated seed sources of Lotus scoparius may significantly lower the fitness of augmented or restored populations. Genetic and environmental similarities of source populations relative to the transplant site should be considered when choosing source materials, a practice recommended by recent seed transfer policies. Geographic separation was not a good surrogate for either of these measures.