Chloroplast DNA evidence for introgression and long distance dispersal in the desert annualSenecio flavus (Asteraceae)

Phylogenetic analysis of chloroplast DNA (cpDNA) restriction site variation supports a close genetic relationship between the Southwest AsianSenecio flavus subsp.breviflorus and the North AmericanS. mohavensis. The intercontinental disjunct distribution of these two desert annuals may have originated via long distance dispersal. The chloroplast genomes of the Southern and North AfricanS. flavus subsp.flavus and subsp.breviflorus differ by at least ten restriction sites, while at most two restriction sites differentiate the cpDNA genomes of subsp.breviflorus and the outgroupS. squalidus. This suggests that the cpDNA genome ofS. flavus subsp.breviflorus may have resulted from introgression and chloroplast capture with a Mediterranean species related toS. squalidus. This hypothesized introgression could account for the morphological distinctiveness and duplicated isozyme loci ofS. flavus subsp.breviflorus relative to subsp.flavus.     

Isozyme analysis of intercontinental disjuncts within Styrax (Styracaceae): implications for the Madrean —Tethyan hypothesis

Various hypotheses have been put forward to explain the presence of sclerophyllous plant disjuncts between western North America and the Mediterranean region. The Madrean–Tethyan hypothesis postulates that the two regions were floristically connected in the Early to Middle Tertiary by way of a low-latitude migration route. Others deny the possibility of such a route, and instead postulate convergence to xerophytic conditions from more widespread mesophytic ancestors, or suggest long-distance dispersal scenarios. One example of a “Madrean–Tethyan link” between the two regions is composed of four species within the genus Styrax: S. officinalis subsp. officinalis from the Mediterranean region, S. officinalis subsp. redivivus and subsp. fulvescens from California, and three closely related species in Texas and northeastern Mexico (S. texanus, S. platanifolius, and S. youngiae). This group was examined with isozymes to assess whether patterns of genetic variation are consistent with those predicted by the Madrean–Tethyan hypothesis. Ten populations from California, six from the Mediterranean region, and three from Texas were sampled. Pairwise comparisons revealed mean genetic identity (I) estimates of 0.581 between Mediterranean and California populations, 0.470 between Mediterranean and Texas populations, and 0.640 between California and Texas populations. Two populations of a species thought by many to be the closest relative of S. officinalis on morphological grounds (S. jaliscanus) exhibited low I (0.299–0.321) relative to all other group comparisons. Intercontinentally disjunct populations of S. officinalis possessed an I value that warrants species status for the Californian and Mediterranean groups. Divergence time estimates between Madrean and Tethyan Styrax range from 5.0 to 13.8 Mya, too recent to be consistent with the Madrean–Tethyan hypothesis. However, alternative explanations for this disjunction are suboptimal in that they require the invocation of either long-distance dispersal, which appears unlikely in this group, or extinction. Nonetheless, the evidence presented here and in other recent studies casts substantial doubt on the Madrean–Tethyan hypothesis as a general explanation for the presence of Madrean and Tethyan taxa similar in overall appearance. More plants with Madrean–Tethyan distributions must be sampled before definitive conclusions regarding this aspect of Madrean and Tethyan vegetation can be reached.     

Chloroplast DNA and isozyme evidence on the evolution ofSenecio vulgaris (Asteraceae)

Chloroplast DNA (cpDNA) and isozyme variation were analyzed over a range of populations of two infraspecific taxa of the tetraploidSenecio vulgaris. The isozyme data were supportive of the hypothesis that the weedy and cosmopolitanS. vulgaris var.vulgaris is an evolutionary derivative ofS. vulgaris subsp.denticulatus from the coasts of W Europe and montane altitudes in S Spain and Sicily. The two taxa exhibited a very high genetic identity with subsp.denticulatus containing slightly more isozyme diversity than was found in var.vulgaris. — Three cpDNA haplotypes (A, B, C) already known from other Mediterranean diploid species ofSenecio were resolved in var.vulgaris, and an additional fourth haplotype (E) was found in subsp.denticulatus. Two alternative hypotheses were chosen to account for the origin and maintenance of the observed cpDNA composition ofS. vulgaris. It either reflects (1) the retention of an ancestral polymorphism which stems from the recurrent and polytopic formation of ancestral tetraploid lineages; or (2)S. vulgaris originally was characterized by haplotype E, and haplotypes A, B and C were acquired through repeated introgressive hybridization with related diploid species. The finding that very low levels of nuclear (isozyme) diversity were present in both taxa ofS. vulgaris examined supports the second of these two hypotheses; however, more detailed analysis of nuclear genetic diversity is required before a firm conclusion can be reached on this matter.Dedicated to emer. Univ.-Prof. DrFriedrich Ehrendorfer on the occasion of his 70th birthday     

Lectotypification of the Bertoloni's names in the genus Senecio L. (Asteraceae)

Original material of the four Senecio taxa described by A. Bertoloni has been examined, and the typification of their names is discussed. A specimen from the Monti Herbarium (kept in BOLO) and iconographies from Bonanni and Bertoloni are designated as lectotypes, whereas another specimen from the Monti Herbarium is selected as neotype. The nomenclature of the names Senecio erucifolius L., Senecio tenuifolius Jacq., Senecio delphinifolius Vahl and Senecio rupestris Waldst. & Kit. is also analysed. The names S. crinitus Bertol. and S. laciniatus Bertol. belong to S. delphinifolius [now Jacobaea delphinifolia (Vahl) Pelser & Veldkamp] and S. rupestris [now Senecio squalidus subsp. rupestris (Waldst. & Kit.) Greuter], respectively, whereas S. erraticus Bertol. and S. praealtus Bertol. are accepted as separate taxa as Jacobaea erratica (Bertol.) Fourr. and Jacobaea erucifolia subsp. praealta (Bertol.) Greuter & B.Nord., respectively.     

Phylogeography of the ground squirrel subgenus Xerospermophilus and assembly of the Mojave Desert biota

Aim The Mohave ground squirrel (Xerospermophilus mohavensis) is one of a few endemic species of the Mojave Desert of south‐western North America. We describe phylogeographic patterns within this species and its sister taxon (Xerospermophilus tereticaudus) and test hypotheses concerning their biogeographical history using genetic signatures of stable versus expanding populations. We compare these patterns with those of other Mojave species to evaluate the role of vicariance in producing phylogeographic structure during the assembly of the Mojave Desert biota. Location The Mojave Desert and adjacent desert regions of south‐western North America. Methods Complete cytochrome b gene sequences of X. mohavensis (46 individuals representing 11 localities) and X. tereticaudus (38 individuals representing 14 localities) were analysed using Bayesian methods to infer phylogenetic relationships. Genetic signals of stable or expanding populations were examined based on the distribution of recent mutations and pairwise differences, as well as with a coalescent‐based approach. Results The two species are reciprocally monophyletic and may have diverged in response to the late Pliocene–early Pleistocene uplift of the Transverse Ranges and Mojave block. Little phylogeographic structure is evident within X. mohavensis, but there is a signature of northern expansion from a presumably full‐pluvial refugium in the Mojave River basin. Four geographic subgroups are evident within X. tereticaudus, and there is a signature of northern expansion from a presumably full‐pluvial refugium in the Sonoran coastal plains. Roughly congruent phylogeographic patterns are found within five arid‐adapted taxa, indicating a strong element of vicariance during the assembly of the generally transitional Mojave Desert biota. Main conclusions We present a preliminary model for the historical assembly of the Mojave Desert biota that indicates a strong vicariant element producing autochthonous lineages (including X. mohavensis) that diverged during the major geological and climatic events of the last 5 Myr. Phylogeographic partitioning within the Mojave Desert underscores the necessity of immediate conservation measures for this unique and fragile arid ecosystem that is locked between two large metropolitan population centres and is the target of continued adverse environmental impact.     

Genetical variation in two related annual Senecio species occurring on the same habitat

Isoenzyme analysis of 14 different enzymes of 4 Netherlands populations of Senecio sylvaticus and 3 populations of S. viscosus, two closely related, partly co-occurring annual pioneer species on clearings, revealed that no genetical variation exists within nor between populations of these species. Differences between the species are used to estimate genetic identity and genetic distance.The possible cause of this genetical invariability is discussed in view of the constant confrontation with the founder situation on clearings, together with the pollination mechanism and the niche breadth of both species.     

Phylogeographic diversification of antelope squirrels (Ammospermophilus) across North American deserts

We investigated the biogeographic history of antelope squirrels, genus Ammospermophilus, which are widely distributed across the deserts and other arid lands of western North America. We combined range‐wide sampling of all currently recognized species of Ammospermophilus with a multilocus data set to infer phylogenetic relationships. We then estimated divergence times within identified clades of Ammospermophilus using fossil‐calibrated and rate‐calibrated molecular clocks. Lastly, we explored generalized distributional changes of Ammospermophilus since the last glacial maximum using species distribution models, and assessed responses to Quaternary climate change by generating demographic parameter estimates for the three wide‐ranging clades of A. leucurus. From our phylogenetic estimates we inferred strong phylogeographic structure within Ammospermophilus and the presence of three well‐supported major clades. Initial patterns of historical divergence were coincident with dynamic alterations in the landscape of western North America, and the formation of regional deserts during the Late Miocene and Pliocene. Species distribution models and demographic parameter estimates revealed patterns of recent population expansion in response to glacial retreat. When combined with evidence from co‐distributed taxa, the historical biogeography of Ammospermophilus provides additional insight into the mechanisms that impacted diversification of arid‐adapted taxa across the arid lands of western North America. We propose species recognition of populations of the southern Baja California peninsula to best represent our current understanding of evolutionary relationships among genetic units of Ammospermophilus. © 2013 The Linnean Society of London, Biological Journal of the Linnean Society, 2013, 109 , 949–967.     

Isozymes as molecular markers for diploid and tetraploid individuals ofNajas marina (Najadaceae)

The genetic variability of five natural populations ofNajas marina L., i.e. one diploid of subsp.marina (Europe), two of subsp.intermedia (Europe) and both a diploid (C. Africa) and a tetraploid (Middle East) of subsp.armata, has been estimated by means of electrophoretic studies. These populations differ in their morphology and karyotype. Emphasis is placed on the characteristics and status of a tetraploid cytotype from Merkaz Sappir (Israel). Almost all the variation observed is expressed in seed alcohol dehydrogenase (ADH). The differences are in a unique allele of theAdh-2 locus and in the formation of novel heteromeric isozymes.Adh genes in seeds can be used as a marker for the autotetraploid character. The other enzyme systems tested failed in this respect. The genetic variability based on 23 loci is rather low. Nevertheless, the autotetraploid population has a higher or equal ratio of polymorphic loci than the related diploids. Cluster analysis illustrated not only thatNajas marina subsp.marina has diverged much from subsp.intermedia and subsp.armata, but also showed the difference between the latter two taxa, as well as the intermediate position of the autotetraploid population.     

Differentiation patterns in the E. MediterraneanScutellaria rubicunda group (Lamiaceae)

Strict sterility barriers where found between theScutellaria populations on Sicily and the Greek populations. The material from Samos is separated by a strict sterility barrier from the other Greek populations. In contrast, the populations on mainland Greece and adjacent islands are all ± interfertile. Three species are recognized,S. rubicunda Hornem., endemic to Sicily, andS. brevibracteata subsp.icarica, endemic to Samos and Ikaria. All other populations are referred toS. rupestris with eight subspecies, most of which are endemic to one island or to one mountain. Three new subspecies are described, viz. subsp.rechingeri and subsp.olympica, endemic to mt Vourinos and mt Olympus in North Greece, respectively, and subsp.caroli-henrici, native to the Malea peninsula of Peloponnisos. The phytogeographical connections and genetic differentiation within and between populations are discussed.Dedicated to Prof. DrK. H. Rechinger on the occasion of his 80th birthday.     

Comparative floral and vegetative differentiation between two European Aquilegia taxa along a narrow contact zone

As a first step in determining the identity and relative importance of the evolutionary forces promoting the speciation process in two closely related European taxa of Aquilegia, we investigated the levels of morphological variation in floral and vegetative characters over the narrow region where their ranges enter into contact, and evaluate the relative importance of both types of traits in their differentiation. A total of 12 floral and ten vegetative characters were measured on 375 plants belonging to seven A. vulgaris populations and six A. pyrenaica subsp. cazorlensis populations located in southeastern Spain. Floral and vegetative morphological differentiation occur between taxa and among populations within taxa, but only vegetative characters (particularly plant height and leaf petiolule length) contribute significantly to the discrimination between taxa. Differentiation among populations within taxa is mostly explained by variation in floral traits. Consequently, morphological divergence between the two taxa cannot be interpreted as an extension of among-population differences occurring within taxa. Multivariate vegetative, but not floral, similarity between populations could be predicted from geographical distance. Moreover, the key role of certain vegetative traits in the differentiation of A. vulgaris and A. p. cazorlensis could possibly be attributable to the contrasting habitat requirements and stress tolerance strategies of the two taxa. These preliminary findings seem to disagree with the currently established view of the radiation process in the genus Aquilegia in North America, where the differentiation of floral traits seems to have played a more important role.     

Quinua and Relatives (Chenopodium sect.Chenopodium subsect.Celluloid)

Traditionally viewed as an Andean grain crop,Chenopodium quinoa Willd. includes domesticated populations that are not Andean, and Andean populations that are not domesticated. Comparative analysis of leaf morphology and allozyme frequencies have demonstrated that Andean populations, both domesticated(quinua) and free-living(ajara), represent an exceptionally homogeneous unit that is well differentiated from allied domesticates of coastal Chile(quingua) and freeliving populations of the Argentine lowlands(C. hircinum). This pattern of relationships indicates that Andean populations represent a monophyletic crop/weed system that has possibly developed through cyclic differentiation (natural vs. human selection) and introgressive hybridization. Relative levels of variation suggest that this complex originated in the southern Andes, possibly from wild types allied withC. hircinum, with subsequent dispersal north to Colombia and south to the Chilean coast. Coastal populations were apparently isolated from post-dispersal differentiation and homogenization that occurred in the Andes. Other data point toward a center of origin in the northern Andes with secondary centers of genetic diversity subsequently developing in the southern Andes and the plains of Argentina. Comparative linkage of South American taxa, all tetraploid, with North American tetraploids of the subsection will eventually clarify this problem. While the possibility of a direct phyletic connection betweenC. quinoa and the Mexican domesticate(C. berlandieri subsp. nuttalliae,) cannot be excluded, available evidence indicates that the latter represents an autonomous lineage that is associated with the basal tetraploid, C. b. subsp.berlandieri, through var.sinuatum, whereas South American taxa show possible affinities to either var. zschackei or var.berlandieri. An extinct domesticate of eastern North America,C. b. subsp.jonesianum, represents either another instance of independent domestication, possibly from subsp. b. var.zschackei, or a northeastern outlier of subsp.nuttalliae.     

Chromosome numbers and pollen fertility in the Senecio nemorensis group (Compositae) in the Carpathians

New chromosome numbers for two species from the Senecio nemorensis group: S. dacicus (2n = 40) and S. ucranicus (2n = 40) have been ascertained. The counts for S. germanicus Wallr. subsp. germanicus (2n = 40), S. hercynicus Herborg subsp. hercynicus (2n = 40), S. ovatus (P. Gaertn. et al.) Willd. subsp. ovatus (2n = 40) occurring in the Carpathians are also reported. The study confirmed only the known tetraploid chromosome number for the taxa of this group. The pollen fertility ranged from 82.09 to 92.99% in all examined species and subspecies, including their hybrids.     

Global mitochondrial DNA phylogeography and biogeographic history of the antitropically and longitudinally disjunct marine bryozoan Membranipora membranacea L. (Cheilostomata): another cryptic marine sibling species complex?

The origin of disjunct distributions in high dispersal marine taxa remains an important evolutionary question as it relates to the formation of new species in an environment where barriers to gene flow are not always obvious. To reconstruct the relationships and phylogeographic history of the antitropically and longitudinally disjunct bryozoan Membranipora membranacea populations were surveyed with mtDNA cytochrome oxidase 1 (COI) sequences across its cosmopolitan range. Maximum parsimony, maximum likelihood and Bayesian genealogies revealed three deep clades in the North Pacific and one monophyletic clade each in the southeast Pacific (Chile), southwest Pacific (Australia/New Zealand), North Atlantic and southeast Atlantic (South Africa). Human-mediated dispersal has not impacted M. membranacea’s large-scale genetic structure. M. membranacea did not participate in the trans-arctic interchange. Episodic long-distance dispersal, combined with climatic vicariance can explain the disjunct distribution. Dispersal led southward across the tropics perhaps 13 mya in the East Pacific and again northwards perhaps 6 mya in the Eastern Atlantic to colonize the North Atlantic from the south, and along the West Wind Drift to colonize Australia. The clades differentiated over evolutionary time in their respective ocean region, potentially forming a sibling species complex. The taxonomic status of the clades is discussed.     

Population genomic evidence for plant glacial survival in Scandinavia

Quaternary glaciations have played a major role in shaping the genetic diversity and distribution of plant species. Strong palaeoecological and genetic evidence supports a postglacial recolonization of most plant species to northern Europe from southern, eastern and even western glacial refugia. Although highly controversial, the existence of small in situ glacial refugia in northern Europe has recently gained molecular support. We used genomic analyses to examine the phylogeography of a species that is critical in this debate. Carex scirpoidea Michx subsp. scirpoidea is a dioecious, amphi‐Atlantic arctic–alpine sedge that is widely distributed in North America, but absent from most of Eurasia, apart from three extremely disjunct populations in Norway, all well within the limits of the Weichselian ice sheet. Range‐wide population sampling and variation at 5,307 single nucleotide polymorphisms show that the three Norwegian populations comprise unique evolutionary lineages divergent from Greenland with high between‐population divergence. The Norwegian populations have low within‐population genetic diversity consistent with having experienced genetic bottlenecks in glacial refugia, and host private alleles that probably accumulated in long‐term isolated populations. Demographic analyses support a single, pre‐Weichselian colonization into Norway from East Greenland, and subsequent divergence of the three populations in separate refugia. Other refugial areas are identified in North‐east Greenland, Minnesota/Michigan, Colorado and Alaska. Admixed populations in British Columbia and West Greenland indicate postglacial contact. Taken together, evidence from this study strongly indicates in situ glacial survival in Scandinavia.     

ELECTROPHORETIC STUDY OF THE ALLOPOLYPLOIDAL ORIGIN OF TALINUM TERETIFOLIUM AND THE SPECIFIC STATUS OF T. APPALACHIANUM (PORTULACACEAE)

Electrophoretic evidence supported the hypothesis that Talinum teretifolium is an allopolyploid derivative of T. mengesii and T. parviflorum. Electrophoretic variation was examined for 384 individuals from 21 populations of four Talinum species. Plants were scored for isozymes of nine enzyme systems specified by 23 gene loci of which 4 were monomorphic and 19 polymorphic. Talinum teretifolium populations were electrophoretically uniform, and all alleles of this species were accounted for by combining alleles present in its presumed parents. Genetic identity values between T. teretifolium and each of its presumed parents (I ≥ 0.817) were higher than between any other pair of the four Talinum species examined. The electrophoretic evidence did not support an alternative hypothesis that T. calycinum is a progenitor of T. teretifolium. Electrophoretic data also showed that T. appalachianum is a disjunct population of T. parviflorum. The average genetic identity between T. appalachianum and T. parviflorum (I = 0.884) was higher than the average genetic identity for conspecific populations of both T. mengesii and T. calycinum.     

Genetic diversity in the Centaurea cineraria group (Compositae) in Sicily using isozymes

Abstract

The genetic diversity of seven taxa endemic to Sicily, C. cineraria, C. busambarensis, C. ucriae subsp. ucriae, C. ucriae subsp. umbrosa, C. todari, C. erycina and C. saccensis, from 11 localities was investigated using isozymes. Eight loci from five enzyme systems (IDH, MDH, PGD, PGM and PGI) were examined. A total of 19 alleles were identified, some rare and two of them exclusive to different populations. The allelic frequencies and the genetic variability values for each population were calculated. On the whole, the genetic diversity, i.e., average polymorphism (P) = 0.41, average number of alleles per locus (A) = 1.75, Nei's gene diversity (H) = 0.18, is moderate, with the highest genetic variability found in the populations of C. todari. The dendrogram shows two major groups: the first consists of all Sicilian populations except those of C. todari; the second of C. cineraria from the region of Campania and C. todari.     

Phylogeographic analysis of the nocturnal velvet ant genus Dilophotopsis (Hymenoptera: Mutillidae) provides insights into diversification in the Nearctic deserts

Understanding the history of diversification in the North American deserts has long been a goal of biogeographers and evolutionary biologists. Although it appears that a consensus is forming regarding the patterns of diversification in the Nearctic deserts in vertebrate taxa, little work has been done exploring the historical biogeography of widespread invertebrate taxa. Before a robust model of geobiotic change in the North American deserts can be proposed, it needs to be determined whether the same historical events affected vertebrate and invertebrate taxa in the same way. We explore the phylogeographic patterns in a widespread nocturnal wasp genus Dilophotopsis using two rDNA loci, the internal transcribed spacer regions 1 and 2 (ITS1 and ITS2). We use Bayesian phylogenetic analysis and haplotype network analysis to determine whether a consistent geographic pattern exists among species and populations within Dilophotopsis. We also used molecular dating techniques to estimate divergence dates of the major phylogenetic clades. Our analyses indicates that the species‐level divergences in Dilophotopsis occurred in the Neogene, and likely were driven by mountain building during the Miocene–Pliocene boundary (approximately 5 Mya) similar to the divergences in many vertebrate taxa. The population‐level divergences within species occurred during the Pleistocene (0.1–1.8 Mya). The present study shows that similar patterns of diversification exist in vertebrate and invertebrate taxa. © 2010 The Linnean Society of London, Biological Journal of the Linnean Society, 2010, 101 , 360–375.     

Palatability to a generalist herbivore,defence and growth of invasive and native <Emphasis Type="Italic">Senecio</Emphasis> species: testing the evolution of increased competitive ability hypothesis

This paper tests the prediction that introduced plants may become successful invaders because they experience evolutionary changes in growth and defence in their new range [evolution of increased competitive ability hypothesis (EICA)]. Interspecific and intraspecific binary feeding choices were offered to the snail Helix aspersa. The choices were between: (1) plants of the invasive Senecio inaequidens and Senecio pterophorus derived from populations in the introduced range (Europe) and plants of three indigenous species (Senecio jacobea, Senecio vulgaris and Senecio malacitanus) from populations in Europe; (2) plants of the invasive S. inaequidens and S. pterophorus from populations in the introduced range (Europe) and from populations in the native range (South Africa). We did not find a clear pattern of preference for indigenous or alien species of Senecio. However, we found that European invasive populations of S. inaequidens and S. pterophorus were less palatable than South African native populations. Moreover, in contrast to the predictions of the EICA hypothesis, the invasive genotypes of both species also showed a higher total concentration of pyrrolizidine alkaloids, and in the case of S. inaequidens we also found higher growth than in native genotypes. Our results are discussed with respect to the refinement of the EICA hypothesis that takes into account the difference between specialist and generalist herbivores and between qualitative and quantitative defences. We conclude that invasive populations of S. inaequidens and S. pterophorus are less palatable than native populations, suggesting that genetic differentiation associated with founding may occur and contribute to the plants’ invasion success by selecting the best-defended genotypes in the introduced range.     

Genetic structure of two endangered pitcher plants,Sarracenia jonesii and Sarracenia oreophila (sarraceniaceae)

Sarracenia jonesii and S. oreophila arc insectivorous perennial plants of the southeastern United States. Both pitcher plant taxa arc rare and endangered. Allozyme diversity was assessed for eight of the ten extant populations of S. jonesii and 14 of the 35 remaining S. oreophila populations. Genetic diversity was low and comparable for both species (H_es = 0.086 and 0.082 for S. jonesii and S. oreophila, respectively). Mean population genic diversity (H_ep) was 0.061 for S. jonesii and 0.060 for S. oreophila. Estimates of genetic diversity were typical of those commonly associated with endemic species. Small populations of each species and geographically disjunct populations tended to maintain less genetic diversity. Indirect estimates of gene flow were comparable for S. oreophila (Nm = 1.62) and S. jonesii (Nm = 1.07).     

Hordein polymorphism in diploid and tetraploid Mediterranean populations of the Hordeum murinum L. complex

Polymorphism analyses of the hordeins, main storage proteins in barley, were conducted on 35 natural populations of Hordeum murinum s.l. from North Africa; this specific complex includes three subspecies with two ploidy levels: H. murinum subsp. glaucum (2n=2x=14), H. murinum subsp. leporinum and subsp. murinum (2n=4x=28). Twenty of these populations belong to the diploid subsp. glaucum, 14 other tetraploid populations belong to the subsp. leporinum. In addition, six populations of the tetraploid murinum were sampled in France: two along the Mediterranean coast and four in Brittany. The polymorphism observed in the electrophoretic patterns highlights strong correlations between bioclimatic features and di- and tetraploid taxa distribution. Moreover, the variation was not randomly distributed within the different ploidy levels, and is correlated with environmental factors. The ecological differentiation of the two main taxa, H. murinum subsp. leporinum and subsp. glaucum is clearly highlighted.