A new species in the genus Dioon (Zamiaceae) from north-central Oaxaca, Mexico

Dioon argenteum sp. nov. (Zamiaceae) is described from northern Oaxaca, México. Flat leaves, and persistently tomentose, slightly imbricate leaflets with marginal prickles characterize this species. The specific epithet argenteum was chosen to describe the silver appearance of the persistent tomentum covering the new leaves. D. argenteum appears to have affinities with D. purpusii and D. califanoi.   © 2003 The Linnean Society of London, Botanical Journal of the Linnean Society , 2003, 141 , 471–476.     

A new species of Valantia (Rubiaceae) from Spain

A new species of Valantia , V. lainzii Devesa & Ortega-Olivencia, endemic to the coastal zone of Granada (southern Spain) is described. The species recalls V. muralis L. in its general aspect, and V. deltoidea Brullo in the type of fructiferous body.  © 2003 The Linnean Society of London, Botanical Journal of the Linnean Society , 2003, 143 , 331–335.     

A new species of Scorzonera L. (Asteraceae) from south Anatolia, Turkey

A new species Scorzonera gokcheoglui O. Ünal & R. S. Göktürk sp. nov. from south Anatolia is described and illustrated. Its relationships with S. argyria and S. pisidica are discussed. A map showing the distribution of the species and other related species is given.  © 2003 The Linnean Society of London, Botanical Journal of the Linnean Society , 2003, 142 , 465–468.     

A new Dryopteris (Pteropsida: Dryopteridaceae) species from south-central Africa

Dryopteris katangaensis , a new species endemic to the Katango–Zambian centre of endemism (Congo-Zambezi watershed) in Zambia and the Democratic Republic of Congo is described and illustrated. The morphological differences between the new species and D. schimperiana are discussed, and the ferns endemic to the Katango–Zambian Centre are reviewed.  © 2003 The Linnean Society of London, Botanical Journal of the Linnean Society , 2003, 142 , 237–242.     

Astragalus neo-assadianus (Fabaceae), a new species in sect. Alopecuroidei from Iran

Astragalus neo-assadianus (Fabaceae), a new species endemic to Iran, is described and illustrated. This species belongs to A. sect . Alopecuroidei and is distinct and interesting among the Iranian species. It is confined to the north-eastern part of Iran (Khorasan Province) and only known from a single collection close to the Turkmenistan frontier.  © 2003 The Linnean Society of London, Botanical Journal of the Linnean Society , 2003, 143 , 197–200.     

Some remarks on the genus Astragalus sect. Incani in Iran

New findings are given for the Astragalus sect. Incani , which occurs within the area covered by the Flora of Iran. Astragalus wojciechowskianus Ranjbar is described as a new species. A. procerus Boiss. & Hausskn . , A. cottonianus Aitch. & Baker, A. achundovii Grossh., A. orduabadensis Grossh. and A. glaucophyllus Bunge are reported as new records for the flora of Iran .   © 2003 The Linnean Society of London, Botanical Journal of the Linnean Society , 2003, 143 , 443–447.     

Karyology of some Brazilian species of Alismataceae

The family Alismataceae ( sensu Cronquist) comprises 11 genera and 75 species of aquatic and semiaquatic herbs. In Brazil, only the two most speciose genera, Echinodorus Rich. ex Engelm. and Sagittaria L., are present. The chromosome number 2 n  = 22 is common to all species. We present karyotypes for eight species, together with their asymmetry index (TF%) and total chromatin length (TCL). All karyotypes have high karyotypic asymmetry and TCL, due to their large and mostly acrocentric chromosomes. The chromosomal evolution of the Alismatidae group is discussed.  © 2003 The Linnean Society of London, Botanical Journal of the Linnean Society , 2003, 143 , 159−164.     

A new species of Silene (Caryophyllaceae) from South Anatolia, Turkey

Silene doganii A.Duran & Y.Menemen sp. nov. from the Amanos Mountains (C6: Osmaniye-Turkey) is described and illustrated. It is closely related to S. caramanica Boiss. & Heldr., from which it differs mainly in its habit, hairiness, leaf and floral features.  © 2003 The Linnean Society of London, Botanical Journal of the Linnean Society , 2003, 143 , 109−113.     

Shoot and compound leaf comparisons in eudicots: dynamic morphology as an alternative approach

Recent developmental studies suggest that the compound leaf is a more or less incompletely developed shoot. Instead of treating compound leaves and shoots as non-homologous, this interpretation draws a continuum between them. The present work considers the plant as a hierarchical series of units on which similar developmental processes are at work, and where each level (shoot, compound leaf, leaflet) is 'repeated' by the next higher level. Measurements related to the expression of developmental processes operating on leaves at the shoot level and on leaflets at the compound leaf level were used to determine if similar processes are at work at these different levels during early stages of organogenesis. Plants with compound leaves showing acropetal leaflet inception, representing a total of 16 species from ten eudicot families, were studied. Based on several types of quantitative analyses, there appears to be a continuum between so-called shoots, compound leaves and leaflets in the species studied. This perspective, qualified as dynamic morphology, both parallels and complements the classical interpretation.  © 2003 The Linnean Society of London, Botanical Journal of the Linnean Society, 2003, 143, 219−230.     

The dynamic clonal genome and its adaptive potential

Populations of clonal organisms are often represented as being evolutionary inert with persistent genetic fidelity. The advent of molecular methods and the corresponding increased genetic resolution of clonal populations forces a reconsideration of this viewpoint. We review molecular data from viruses, prokaryotes and eukaryotes to support the argument that clones possess a highly dynamic and adaptive genome.  © 2003 The Linnean Society of London, Biological Journal of the Linnean Society , 2003, 79 , 193–208.     

Studies on Thapsia (Apiaceae) from north-western Africa: a forgotten and a new species

Following a revision of Thapsia (Apiaceae) in north-western Africa, the name Thapsia platycarpa is resurrected and lectotypified for a species that grows between Algeria and Morocco, and a new species Thapsia cinerea is described from the Rif region of north-eastern Morocco. Morphological features that differentiate between these and other species ( T. villosa , T. garganica , T. transtagana and T. gymnesica ) are discussed. An identification key for the plants of the area is presented.  © 2003 The Linnean Society of London, Botanical Journal of the Linnean Society , 2003, 143 , 433–442.     

A new diploid Hieracium (Asteraceae: Lactuceae) from Bulgaria

Hieracium kittanae Vladimirov, a new diploid (2 n  = 18) species restricted to a few gorges in the Central Rhodope Mountains, south Bulgaria, is described and illustrated. It occurs in crevices of limestone rock in shady to sunny places with high atmospheric humidity. Morphologically, it to some extent resembles taxa from the H. glaucinum and H. schmidtii groups, but is otherwise very distinct, without close relatives in the Rhodope and neighbouring mountains.  © 2003 The Linnean Society of London, Botanical Journal of the Linnean Society, 2003 , 143 , 213−218.     

A new species of Ceratozamia (Zamiaceae, Cycadales) from Veracruz, Mexico

Ceratozamia huastecorum sp. nov. is from an isolated meseta or tepui-like mountain in the Huasteca region of northern Veracruz State, Mexico. It has affinity to C. morettii Vázq.Torres & Vovides from the Mexican transvolcanic mountain range, which lies over 200 km to the south. The most notable differences are in female cone colour, leaf and leaflet morphology and length. The specific epithet is chosen in honour of the Huasteca ethnic region of great cultural importance to northern Veracruz.  © 2003 The Linnean Society of London, Botanical Journal of the Linnean Society , 2003, 141 , 395–398.     

A new violet species (Violaceae) from the south-west Alps

Viola laricicola Marcussen sp. nov. is described from collections from four French and Italian localities in the south-west Alps. It is closely related to V. riviniana (section Trigonocarpea ) but differs in a few morphological characters and by the chromosome number 2 n  = 20. Viola laricicola is endemic to the montane and subalpine coniferous forests in the continental parts of the Alps.  © 2003 The Linnean Society of London, Botanical Journal of the Linnean Society , 142 , 119–123.     

A new species of Hybanthus (Violaceae) from north-eastern Brazil

A new species of Hybanthus (Violaceae) from north-eastern Brazil is described and illustrated. Hybanthus verrucosus Paula-Souza is endemic to 'caatingas' of Bahia and Alagoas states and is very distinct from all other Brazilian species of the genus, for its anterior petal, which is covered with small wart-like outgrowths. Other distinctive characteristics of the new species and its relationship with a closely related species ( H. atropurpureus (A.St.-Hil.) Taub.) are discussed.  © 2003 The Linnean Society of London, Botanical Journal of the Linnean Society , 2003, 141 , 503–506.     

Genetic diversity and structure of the cycad Zamia loddigesii Miq. (Zamiaceae): implications for evolution and conservation

The genetic diversity and structure of four populations of the cycad Zamia loddigesii were studied throughout its range in Mexico. Allozyme electrophoresis of 15 loci was conducted. The mean number of alleles per locus was 1.80 ± 0.09, the percentage of polymorphic loci was 66.6 ± 5.4, and the expected heterozygosity was 0.266 ± 0.02. The results indicated that the genetic diversity was relatively higher, with respect to tropical tree species and other cycads. The genetic variation explained by differences among populations was 18%. On average, gene flow between paired populations was similar ( Nm  = 1.6) to other tropical forest trees and cycad species. Our results indicated that the geographical isolation among populations of Z. loddigesii generated allele loss, as well as a clinal variation in the frequencies of two loci ( MDH and MNR2 ), in relation to the latitudinal distribution of populations. The populations have become fragmented due to increasingly higher pressure of habitat conversion and disturbance. The importance of the establishment of sanctuaries and protected areas and a reduction in deforestation is highlighted in this research as a way of preserving the high genetic diversity of this and other endemic species.  © 2006 The Linnean Society of London, Botanical Journal of the Linnean Society , 2006, 152 , 533–544.     

Minuartia graminifolia (Caryophyllaceae), a south-east European species

A re-evaluation of Minuartia graminifolia has been undertaken based on comparative morphological studies. M. graminifolia subsp. rosani (an endemic of the south-central Apennines and Sicily) and subsp. hungarica (an endemic of the Banat region of Romania) are accepted infraspecific taxa. M. graminifolia subsp. hungarica is lectotypified. M. graminifolia subsp. clandestina is confirmed for Italy; the taxon is neotypified. The type subspecies is considered an endemic to the east-central Alps. Keys to the species of Minuartia ser. Graminifoliae and to the subspecies of M. graminifolia are provided.  © 2003 The Linnean Society of London, Botanical Journal of the Linnean Society , 2003, 143 , 419–432.