Santiago Castroviejo

Vegetación de Doñana (Huelva, España)

Monografia fitosociologica de la vegetacion de la Reserva Biologica y del Parque Nacional de Donana (Huelva, Espana). En base a la publicacion de 461 inventarios y 25 sininventarios se describen 70 asociaciones pertenecientes a 28 clases de vegetacion, asi como se dan a conocer cinco sinasociaciones. De cada asociacion se aportan datos floristicos, ecologicos, estructurales, corologicos y taxonomicos, y en muchos casos sus relaciones con las asociaciones geovicarias. Ademas de numerosos esquemas catenales y dinamicos de la vegetacion, se incluye una lista de los sintaxones y un catalogo alfabetico de las plantas vasculares de Donana y de las comentadas en el texto.

Agmatoploidy in Carex laevigata (Cyperaceae): Fusion and fission of chromosomes as the mechanism of cytogenetic evolution in Iberian populations

In this paper cytogenetic studies on 64 specimens from 20 Iberian populations ofCarex laevigata (Cyperaceae) are presented. Chromosome behaviour in meiosis suggests that the different chromosome numbers obtained (ranging from 2n = 69 to 2n = 80) were distributed according to an increasing geographic gradient of chromosome fission along the North → South direction. Four relatively stable areas were also delimited according to chromosome numbers displayed by this species, i.e. 2n = c. 72, c. 74, c. 76, and 78. The meiotic behaviour ofCarex ×deserta (C. laevigata ×C. binervis) was also studied.

Reliance on the citation index undermines the study of biodiversity

Sir — The popularity of the Science Citation Index (SCI) as a measure of ‘good’ science is damaging basic taxonomic work, without which the study of biodiversity would not be possible. Basic taxonomic work is not highly cited, except in ‘hot’ taxa like the genus Homo. The number of authors citing a paper during the short period of time (ten years) that the SCI uses for its statistics is relatively low. But taxonomy papers continue to be referred to and cited for more than a century after their publication. Almost every good taxonomic paper becomes a classic in the literature. High-quality basic taxonomic work — the description of new taxa and revision of older ones — is expensive and timeconsuming. Many of the most interesting finds are from ‘exotic’ locations, requiring travelling, sampling, preparing, sending back collections, writing descriptions, illustrating and so on. The resulting papers are rated low in the SCI, even when published in high-quality specialist journals, and are unlikely to impress managers or funding agencies. So a paradox arises: concern for biodiversity goes together with a dismissal of the foundation of any biodiversity work, which is the proper description of taxa. If there is reluctance to fund this kind of work because of low citations, and with fewer journals available to publish their findings, the most basic research in biodiversity is doomed to disappear, as is already happening. Antonio G. Valdecasas*, Santiago Castroviejo†, Leslie F. Marcus‡ *Museo Nacional de Ciencias Naturales (CSIC), José Gutierrez Abascal 2, 28006 Madrid, Spain †Real Jardín Botánico (CSIC), Plaza de Murillo 2, 28014 Madrid, Spain ‡Department of Biology, Queens College of City University of New York, Flushing, New York 11367, USA

Cytotaxonomic studies in the sections Spirostachyae (Drejer) Bailey and Ceratocystis Dumort. of the genus Carex L. (Cyperaceae) with special reference to Iberian and North African taxa

LUCERO, M. & CASTROVIEJO, S., 1993. Cytotaxonomic studies in the sections Spirostachyae (Dreyer) Bdey and Ceratocystis Dumort. of the genus Carex L. (Cyperaceoe), with special reference to the Iberian and North African tarn. Karyological studies were carried out on Iberian and North African populations of all species included in sections Spirosfacbae and Ceratocysfis of the genus Carex, with observations made on meiotic divisions in one to seven individuals per population. In the light of the karyological data we present hypotheses of the most probable phylogeny of the section Spirostachyae, and of the relationships of the sections Spirostachyae, Ceratocystis and Elatae. Carex laevigata and C. camposii are transferred from section Elatae to section Spirostachyae.

Typification of two Linnaean names in Araceae: Arum proboscideum L. and Arum muscivorum L. f.

As part of a study of Iberian and Balearic Araceae, two Linnaean names, Arum proboscideum L. and A. muscivorum L. f., are lecto- and neotypified. respectively.

Holcus pintodasilvae (Poaceae, Pooideae, Poeae), a New Species from the Island of Madeira (Portugal), and Notes on Macaronesian Holcus

Abstract.  A new species of Holcus L. (Poaceae), endemic to the island of Madeira (Portugal), is here described as H. pintodasilvae M. Seq. & Castrov. This new species is morphologically closely related to the Macaronesian endemics H. rigidus Hochst. ex Hochst. (Azores Archipelago) and H. mollis L. subsp. hierrensis Stierst. (El Hierro Island, in the Canary Islands) but differs by having the culm nodes light brown, the leaves with a glabrous sheath and subspreading lamina attenuated to an acuminate apex, the glumes blunt, shiny, glabrous (except in the minutely scabrous veins), the upper glume with proximal lateral veins, and the lemma of the upper floret with an awn ca. 4 mm, twice as long as the lemma. Chromosome counts in H. pintodasilvae are tetraploid (2n = 28). Morphology, ecology, biogeography, and conservation issues are discussed and related to other Macaronesian Holcus taxa. Holcus pintodasilvae was found as only three populations (totaling less than 20 individuals), and its IUCN conservation status is Critically Endangered (CR). A new specific status is proposed for H. mollis subsp. hierrensis, as H. hierrensis (Stierst.) Stierst. & M. Seq., based on its chromosome number and morphological identity. Resumo.  Descreve-se uma nova espécie, Holcus pintodasilvae M. Seq. & Castrov., pertencente ao género Holcus L. (Poaceae), endémica da Ilha da Madeira (Portugal). Morfologicamente próxima dos endemismos macaronésicos H. rigidus Hochst. ex Hochst. (Arquipélago dos Açores) e H. mollis L. subsp. hierrensis Stierst. (Ilha de Hierro, Arquipélago das Canárias) diferencia-se por possuir: nós de coloração castanha-clara; folhas com bainhas glabras e lâminas subpatentes atenuadas num ápice acuminado; glumas brilhantes, múticas e glabras (excepto nas nervuras que se apresentam escabriúsculas), gluma superior com as nervuras laterais proximais; lema da flor superior com arista ca. 4 mm (duas vezes o comprimento da lema). Incluem-se ainda resultados da contagem de cromossomas de H. pintosilvae (2n = 28). Discutem-se, e relacionam-se com outros taxa Macaronésicos do género Holcus, aspectos relativos à morfologia, ecologia, biogeografia e conservação. Holcus pintodasilvae foi encontrado em apenas três populações (num total de menos de 20 indivíduos), sendo o seu estado de conservação IUCN está criticamente ameaçado (CR). Propõe-se ainda a combinação H. hierrensis (Stierst.) Stierst. & M. Seq. baseada na sua identidade morfológica e número cromossomático.

Notas citotaxonómicas sobre Sedum acre L. (Crassulaceae)

Se estudian cariologicamente 17 poblaciones espanolas de Sedum acre L., se obtienen 2n=56, nuevo nivel para la especie, ademas de 2n=40, 60, 80 y 100. Del estudio morfologico se desprende que la variabilidad especifica no depende de factores fijos y se desestima el establecimiento de categorias taxonomicas infraespecificas.