Abstract
Medicago intertexta andM. ciliaris have been controversially recognized as separate species. The only reliable diagnostic character, gland-tipped trichomes on the fruits inM. ciliaris, is controlled by presence of a single dominant allele, and such one-character taxonomies are debatable. Contributing to the difficulty,M. muricoleptis andM. granadensis, the other two species ofMedicago sectionSpirocarpos subsectionIntertextae, are sometimes confusingly similar toM. intertexta or to each other. Allozyme differences provided 95% verification of the suitability of the gland-tipped trichome character for separatingM. intertexta andM. ciliaris, thus corroborating their recognition as separate taxa. Several measures of allozyme variation indicated thatM. intertexta is more polymorphic than its sister species. Heterozygosity was also highest inM. intertexta, suggestive of a higher outcrossing rate, which is also consistent with larger floral size. Heterozygosity ofM. intertexta was concentrated in Sicily and nearby countries. Taxonomic difficulties in identifying SicilianM. intertexta are well known, and may be the result of interspecific hybridization and introgression.Medicago muricoleptis differed from the above two species in the frequency of several alleles, whileM. granadensis possessed numerous unique alleles consistent with its complete absence of genetic exchange with the other three substantially interfertile species.
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References
Barrett, S. C. H., 1982: Genetic variation in weeds. — InCharudation, R., Walker, H. L., (Eds): Biological control of weeds with plant pathogens, pp. 73–98. — New York: Wiley.
Cherifi, K., Boussaïd, M., Marrakchi, M., 1993 (1994): Diversité génétique de quelques populations naturelles deMedicago ciliaris (L.)Krock et deMedicago intertexta (L.)Mill. 1. Analyse de la variabilité morphologique. — Agronomie (Paris)13: 895–908.
Crawford, D. J., Ornduff, R., Vasey, M. C., 1985: Allozyme variation within and betweenLasthenia minor and its derivative speciesLasthenia maritima (Asteraceae). — Amer. J. Bot.72: 1177–1184.
Dixon, W. J., (Ed.), 1965: Biomedical computer programs. — Los Angeles: School of Medicine, University of California.
Ginsburg, I., 1938: Arithmetical definition of the species, subspecies and race concept, with a proposal for a modified nomenclature. — Zoologica23: 253–286.
Gottlieb, L. D., 1982: Conservation and duplication of isozymes in plants. — Science216: 373–380.
—, 1984: Electrophoretic analysis of the phylogeny of the self-pollinating populations ofClarkia xantiana. — Pl. Syst. Evol.147: 91–102.
Gower, J. C., 1966a: Some distance properties of latent root and vector methods used in multivariate analysis. — Biometrika53: 325–388
—, 1966b: A Q-technique for the calculation of canonical variates. — Biometrika53: 588–590.
—, 1971: A general coefficient of similarity and some of its properties. — Biometrics27: 857–874.
Hamrick, J. L., Godt, M. J. W., 1990: Allozyme diversity in plant species. — InBrown, A. H. D., Clegg, M. T., Kahler, A. L., Weir, B. S., (Eds): Plant population genetics, breeding, and genetic resources, pp. 43–63. — Sunderland, Mass.: Sinauer.
Heyn, C. C., 1963: The annual species ofMedicago. — Jerusalem: Magnes Press, The Hebrew University.
Lesins, K. A., Lesins, I., 1979: GenusMedicago (Leguminosae), a taxogenetic study. — The Hague: Junk.
—, 1971: Relationship of taxa in the genusMedicago as revealed by hybridization. V. SectionIntertextae. — Canad. J. Genet. Cytol.13: 335–346.
Nei, M., 1972: Genetic distance between populations. — Amer. Naturalist106: 283–292.
Raelson, J. V., Grant, W. F., 1988: Evaluation of hypotheses concerning the origin ofLotus corniculatus (Fabaceae) using isoenzyme data. — Theor. Appl. Genet.76: 267–276.
Rohlf, F. J., 1992: NTSYS-pc, numerical taxonomy and multivariate analysis system, version 1.70. — Setauket, New York: Exeter Software.
Rose, R. J., Schlarbaum, S. E., Small, E., Johnson, L. B., 1988: Chloroplast genomic variation and phylogeny inMedicago sectionIntertextae. — Canad. J. Bot.66: 1352–1358.
Schlarbaum, S. E., Small, E., Johnson, L. B., 1984: Karyotypic evolution, morphological variability, and phylogeny inMedicago sect.Intertextae. — Pl. Syst. Evol.145: 203–222.
Small, E., 1988: Pollen-ovule patterns in tribeTrifolieae (Leguminosae). — Pl. Syst. Evol.160: 195–205.
—, 1994: Additional clarification of theMedicago blancheana-bonarotiana-rotata complex. — Canad. J. Bot.72: 829–831.
—, 1990a: A numerical taxonomic analysis of theMedicago littoralis — M. truncatula complex. — Canad. J. Bot.68: 1667–1674.
—, 1990b: A taxonomic simplification ofMedicago italica. — Canad. J. Bot.68: 2103–2111.
—, 1991: A clarification of theMedicago polyceratia — Medicago orthoceras complex. — Canad. J. Bot.69: 1907–1912.
—, 1989: A synopsis of the genusMedicago (Leguminosae). — Canad. J. Bot.67: 3260–3294.
—, 1982: Character set incongruence inMedicago. — Canad. J. Bot.60: 2505–2510.
—, 1992: Isozyme variation and alleged progenitor-derivative relationships in theMedicago murex complex (Fabaceae). — Pl. Syst. Evol.181: 33–43.
Warwick, S. I., 1990: Allozyme and life history variation in five northwardly colonizing North American weed species. — Pl. Syst. Evol.169: 41–54.
Weeden, N. F., Wendel, I. F., 1990: Genetics of plant isozymes. — InSoltis, D. E., Soltis, P. S., (Eds): Isozymes in plant biology, pp. 46–72. — Portland, Oregon: Dioscorides Press.
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Small, E., Warwick, S.I. & Brookes, B. Allozyme variation in relation to morphology and taxonomy inMedicago sect.Spirocarpos subsect.Intertextae (Fabaceae). Pl Syst Evol 214, 29–47 (1999). https://doi.org/10.1007/BF00985730
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DOI: https://doi.org/10.1007/BF00985730