Botanical Journal of the Linnean Society

JOHNSON, KELLI A.; MAPES, GENE; DOGUZHAEVA, LARISA; ROTHWELL, GAR W.

doi: 10.1111/j.1095-8339.2007.00706.xpmid: N/A

AbstractA new species of Cardiocarpus from the Sim River Basin in the southern Urals of Russia is the first anatomically preserved cardiocarpalean ovule from the Permian of the Angara floral province. Specimens are preserved in a soft organic limestone with large numbers of juvenile bactritoid protoconchs. Ovules are roughly ellipsoidal in the major plane, up to 6.0–7.5 mm in length and 5.3 mm in width, with a diminutive wing and a rounded chalaza. The outer surface of the ovules is smooth. In longitudinal sections, two vascular tissue channels traverse the sclerotesta at the chalaza, and appear to extend to near the apex within each wing. There is a simple, dome-shaped pollen chamber at the apex, which lies below a narrow micropyle. The sclerotesta consists of one or two layers of longitudinally orientated cells at the interior, and sclereids that are radially elongated towards the periphery. The sarcotesta is incompletely preserved, but displays an outer layer of cells that are somewhat elongated towards the long axis of the ovule. Numerical cladistic analysis reveals little correlation between the structure of cardiocarpalean morphotaxa and the phylogenetic relationships of the plants that produced them, where affinities are known. Cardiocarpus angarensis sp. nov. enriches our understanding of Permian spermatophytes in temperate climates of the Northern Hemisphere, and reveals that ovules similar to those of Euramerican and Cathaysian provinces characterized an Angaran spermatophyte.

MÖLLER, MICHAEL; GAO, LIAN-MING; MILL, ROBERT R.; LI, DE-ZHU; HOLLINGSWORTH, MICHELLE L.; GIBBY, MARY

doi: 10.1111/j.1095-8339.2007.00697.xpmid: N/A

AbstractWe used morphological and geographical data of 128 herbarium specimens of the Taxus wallichiana complex in eastern Asia to investigate their utilization in discriminating and identifying taxa included in the complex. One bud scale and 26 leaf characters were used to separate T. fuana, T. wallichiana var. wallichiana, T. wallichiana var. mairei, T. wallichiana var. chinensis and T. sumatrana by K-means clustering and dendrograms using Ward's distance. Out of the 27 characters examined 21 were found to be well correlated with geographical patterns. T. fuana was morphologically the most distant taxon, while T. sumatrana clustered among the T. wallichiana varieties. After correcting misidentifications of the specimens in T. wallichiana, its varieties occupied discrete geographical ranges, except for some limited sympatry of varieties mairei and chinensis east of the Tanaka–Kaiyong line and the Sichuan Basin, China. Our analysis demonstrates the importance of consistency in character selection and definition in the identification of morphologically difficult taxa and the power of combining morphometric and geographical data in clarifying their spatial distribution.

PERUZZI, LORENZO; BARTOLUCCI, FABRIZIO; FRIGNANI, FLAVIO; MINUTILLO, FRANCESCO

doi: 10.1111/j.1095-8339.2007.00710.xpmid: N/A

AbstractGagea tisonianaPeruzzi et al.sp. nov. is described and its taxonomic relationship is discussed. The new species, which appears to be endemic to central Italy, is close to G. pratensis (Pers.) Dumort., G. pusilla (F. W. Schmidt) Sweet, and other mainly poorly known [i.e. G. succedanea Griseb. et Schenk, G. transversalis Stev., and G. paczoskii (Zapal.) Grossh.] or as yet undescribed taxa from eastern Europe and the eastern Mediterranean area. The recognition of the new taxon G. tisoniana is claimed on the basis of anatomical, karyological, ecological, and phytogeographical data. Maps of the Italian distribution of G. pratensis (2n = 60), G. pusilla (2n = 24), and G. tisoniana (2n = 24) are presented, together with an analytical identification key. Finally, G. pratensis is recorded here for the first time in Tuscany (Monte Cetona).

CAMPBELL, VICTORIA V.; ROWE, GRAHAM; BEEBEE, TREVOR J. C.; HUTCHINGS, MICHAEL J.

doi: 10.1111/j.1095-8339.2007.00709.xpmid: N/A

AbstractGenetic variation was examined in five microsatellite loci to seek evidence of genetic differentiation and restricted gene flow that would support the taxonomic division of Gymnadenia into three species (G. borealis, G. conopsea, and G. densiflora). A total of 107 alleles was detected in 17 populations from England, Scotland, and Ireland. The mean expected heterozygosities ranged from 0.48 to 0.81. The differentiation in allele frequencies amongst populations that had been assigned to each taxon on the basis of morphology was sufficiently large to support the taxa as distinct species. Phylogenetic trees based on microsatellite allele frequencies, as well as assignment tests, supported the existence of three distinct groups with at least partial restriction of gene flow between them. There was substantial homozygote excess, leading to high FIS estimates, for most loci in most populations. This is unlikely to have been a result of widespread null alleles, and more probably reflects a high level of inbreeding in G. conopsea. This inference requires further investigation. The implications of the results of this and other taxonomic studies for the conservation of Gymnadenia in Britain are discussed.

DE MICCO, VERONICA; ARONNE, GIOVANNA

doi: 10.1111/j.1095-8339.2007.00705.xpmid: N/A

AbstractMediterranean shrub species are described as having phenology, habitus, reproductive biology and anatomical alterations in certain tissues, allowing their survival during the dry season and protecting them from herbivory. Anatomical and chemical analyses were conducted in 1-year-old branches of Cistus ladanifer L. in order to investigate the role played by shoot structure in the adaptive strategies of this species in the Mediterranean environment. Results showed that both xylem and pith underwent lignification. Pith parenchyma cells had thickened walls, higher lignin content than xylem and different monomer composition. Xylem presented features aiding safe water transport. A large accumulation of phenolic substances was found in xylem, pith and cortical parenchyma. Observations reported in this paper suggest the occurrence of adaptive strategies in 1-year-old branches of C. ladanifer whose structural features: (1) allow mechanical reinforcement of tissues to withstand drought without suffering permanent damage; (2) favour safety rather than efficiency in water transport; (3) defend the plants from animal predation and pathogens by accumulating phenolics in various tissues, and (4) protect inner tissues against UV-B radiation through deposition of phenolic compounds in cortical layers.

STOUT, JANE C.

doi: 10.1111/j.1095-8339.2007.00719.xpmid: N/A

AbstractThe reproductive biology of an exotic species will affect its ability to become naturalized and invasive in non-native habitats. Rhododendron ponticum is an ecologically damaging exotic weed in the British Isles, which spreads predominantly by seed. I investigated how inbreeding and outcrossing affect seed production and germination in a wild population of this species in Ireland. Experimental manipulations revealed low fruit and seed set when insects were excluded from flowers, suggesting that this species has limited capability for spontaneous autogamy. Hand-pollination treatments showed that, although flowers are self-compatible (with self and same plant pollen), higher levels of seed set occur following outcrossing (xenogamy). There was no significant difference in rate of germination of seeds from inbred or outcrossed treatments. The addition of xenogamous pollen to open flowers did not increase fruit or seed set, suggesting that flowers in this population are not pollen limited: native generalist pollinators, mainly bumblebees (Bombus spp.), are providing an adequate pollinator service. This work demonstrates that outcrossing increases seed set and pollinators are required to facilitate this. Hence, generalist native pollinators can promote invasion by exotic plants. Native pollinators can clearly play an important part in alien species invasion.

XUE, CHUN-YING; HO, TING-NONG; LI, DE-ZHU

doi: 10.1111/j.1095-8339.2007.00711.xpmid: N/A

AbstractThe embryological features of three species of Swertia (s.l.)–S. erythrosticta, S. franchetiana, and S. tetraptera– were characterized, and the observations were used, together with previously gathered data on other species, to evaluate a recently proposed polyphyly, based on molecular data, of Swertia s.l. Comparisons of species within the genus showed that they have diversified embryologically, and there are significant between-species differences. Notable features that vary between species include the number of cell layers that form the anther locule wall, the construction of the wall of the mature anther, tapetum origin, the cell number in mature pollen grains, the structure of the fused margins of the two carpels, the ovule numbers in placental cross-sections, the shape of the mature embryo sac, the degree of ovule curvature, antipodal variation and the presence of a hypostase, and seed appendages. They share characters that are widely distributed in the tribe Gentianeae, such as a dicotyledonous type of anther wall formation, a glandular tapetum with uninucleate cells, simultaneous cytokinesis following the meiosis of the microsporocytes, tetrahedral microspore tetrads, superior, bicarpellary and unilocular ovaries, unitegmic and tenuinucellar ovules, Polygonum-type megagametophytes, progamous fertilization, nuclear endosperm, and Solanad-type embryogeny. The presence of variation in embryological characters amongst the species of Swertia s.l. strongly supports the view that Swertia s.l. is not a monophyletic group. Frasera is better separated from Swertia s.l. as an independent genus, and is only distantly related to Swertia s.s. judging from the numerous differences in embryology. Swertia tetraptera is very closely related to Halenia, as they show identical embryology.

AKHANI, HOSSEIN

doi: 10.1111/j.1095-8339.2007.00707.xpmid: N/A

AbstractSouth-West and Central Asia are major centres of diversity in the genus Heliotropium. On the basis of detailed taxonomic studies and information gathered from the literature, a synopsis of 61 known species of Heliotropium and two species of Arguzia in the area is given. Iran, with 32 species and 14 (sub)endemic species, has the highest diversity. The photosynthetic pathways of 42 taxa were determined using the isotope composition method. Except for H. marifolium Retz s.l. and H. rariflorum Stocks, all remaining species analysed showed δ13C values characteristic for C3 photosynthesis. Evidently, by contrast with the families Chenopodiaceae and Polygonaceae, the Irano-Turanian area is not an authochthonous region of developing C4 species in Heliotropium. The distribution maps of 57 taxa are provided and their biogeographical importance is discussed in order to elucidate the distribution patterns in South-West Asia. In the Irano-Turanian region, the Irano-Anatolian province of Zohary, which extends from central Anatolia to the western Himalaya, is a very large and vaguely defined phytochorion that should be split into smaller units. The consideration of southern Iran and adjacent Pakistan as part of the Sudanian or Saharo-Sindian regions (sensu either Zohary or Léonard) cannot be accepted, because most endemic species in this area are either typical Irano-Turanian or isolated relicts. Furthermore, it is concluded that the Saharo-Sindian flora is not an autochthonous flora; most species are of transgressive origin from the surrounding phytochoria. Finally, a new species, Heliotropium ziegleri Akhani, is described from Iran.

RYDING, OLOF

doi: 10.1111/j.1095-8339.2007.00702.xpmid: N/A

AbstractThe material of Micromeria s.s. (M. sect. Micromeria) from tropical to southern Africa and the Arabian Peninsula is revised. The endemic Ethiopian M. unguentaria Schweinf. is retained as a species, while the other African and Arabian material of Micromeria is included in M. imbricata (Forssk.) C. Chr. M. imbricata is divided into the following three varieties: var. imbricata, which is very polymorphic, widespread in the African highlands, and also occurs in Arabia; var. rhodesiaca (Elly Walther & K.H. Walther) Ryding, which occurs in the highlands of Malawi, Mozambique and Zimbabwe; and var. villosa (Elly Walther & K.H. Walther) Ryding, which occurs in montane to alpine areas of Ethiopia and East Africa. Discontinuities in the variation within var. imbricata, observed at some localities, are suggested to be a result of partial autogamy. Problems with delimitation between M. imbricata, the East Asiatic M. biflora (Buch.-Ham. ex D.Don) Benth. and some Mediterranean species are discussed.

Tittley, Ian

doi: 10.1111/j.1095-8339.2007.00701.xpmid: N/A