Aiming to analyze the evolutionary relationships between the diploid species Turnera grandiflora (2n = 2x = 10) and the octoploid T. fernandezii (2n = 8x = 40), inter-specific hybrids were recovered by in vitro embryo rescue methods. The full-grown plants obtained were all pentaploids (2n = 5x = 25) confirming their hybrid nature. The chromosome associations observed in the hybrids during meiosis were indicative for an autopentaploid, suggesting that T. fernandezii carries the genome of T. grandiflora (C^gC^g) but at the octoploid level (C^gC^g C^gC^g C^gC^g C^gC^g). This fact confirms a close evolutionary relationship between the species and supports the hypothesis that T. grandiflora is the progenitor of T. fernandezii. A tentative hypothesis regarding the autopolyploid origin of T. fernandezii is finally formulated.

Astragalus gines-lopezii is a perennial herb, endemic to the south of the Iberian Peninsula. It has been classified as ‘Endangered’ by the Extremadura Regional Catalogue and placed in the equivalent category (EN D) of the National Red List because only one population in the world is known. Conservation of A. gines-lopezii requires a greater understanding of its population size, seed ecology and germination conditions. The latter issues are particularly important when establishing a reintroduction programme. This species was observed in nine colonies on the same mountainside, the largest of which consists of 60 plants. In this study, we compare the ability of the seeds to germinate under various conditions. Unlike most other members of the Fabaceae, the seeds of A. gines-lopezii do not need physical or chemical pre-treatment in order to germinate; instead they require a photoperiod for optimal germination. This study will facilitate a more in-depth understanding of this rare and poorly known species.

Scorzoneroides palisiae, S. salzmannii, and S. muelleri (Asteraceae) are phylogenetically close annuals with dimorphic achenes. Although these three species are characteristic to areas with some degree of disturbance, S. palisiae and S. salzmannii grow in Mediterranean environments, whereas S. muelleri preferentially grows in semi-arid environments. This study compared the germination characteristics of central and peripheral achenes subjected to different storage times. Both central and peripheral achenes of the three Scorzoneroides species were completely dormant immediately after dispersal. This dormancy was reduced after six months in dry storage, and practically disappeared after more than a year in storage. Six-month central achenes of S. palisiae and S. salzmannii displayed lower dormancy levels than peripheral achenes did, producing a mixed germination pattern. However, 6-month central achenes of S. muelleri displayed the same dormancy levels as those of peripheral achenes. Furthermore, there was a nearly significant negative correlation among germination and the annual aridity index in the studied populations. We suggest that this increase in dormancy may be interpreted as an adaptation to semi-arid ecosystems.

Accurate and non-destructive methods to determine individual leaf areas of plants are a useful tool in physiological and agronomic research. Determining an individual leaf area (LA) involves measurements of leaf length (L) and width (W), or some combinations of both parameters. Investigation was carried out in 2008 and 2009 to test whether a model could be developed to estimate leaf area of Bergenia purpurascens along an elevational gradient across a timberline ecotone, southeastern Tibet. A total of 786 leaves, 153–159 leaves for each 100-m elevation range, were measured in June 2008 for model construction. Coefficients of LA models incorporating both leaf dimensions (L and W) or W alone were independent of elevation, suggesting that a common model can be employed to estimate LA across the whole elevation range. A single-variable model using the leaf width (LA = 1.44W^1.90), which was simpler, more convenient and also allowed reliable LA estimations, was developed. By applying this equation to another independent dataset from a later experiment in June 2009 for model validation, we found that observed and predicted LAs exhibited a high degree of correlation (R² = 0.95). Therefore, this model can accurately estimate the leaf area of B. purpurascens across a timberline ecotone without use of any instruments.

We studied the germination of Erica australis seeds and their responses to different treatments (high temperature, acidic condition, cold stratification, gibberellic acid applications). Germination was very low in untreated seeds (3%) and required approximately one month to start, but increased in all the treatments tested, reaching a value of 100% when seeds were treated with gibberellic acid (25 ppm). Exposure to heat and to low pH promotes germination and reduces time to germinate, which indicates that germination is related to passage of fire and to soil pH. Germination of this species is also correlated with wet and cold conditions and dormancy can be classified as being of the physiological type.

Antimonite precipitation was used to detect Ca² in the stigmas and styles of lettuce (Lactuca sativa) before and after pollination. Abundant calcium precipitates were detected in the papillae walls on the receptive surface of the stigma both before and after pollination. Meanwhile, few calcium granules were observed in the wall of epidermal cells on the non-receptive surface. Before pollination, calcium formed a gradient from the top to the base of the style in the transmitting tissue and parenchyma cells. After pollination, calcium levels increased in the transmitting tissue, and the gradient distribution became stronger. The calcium gradient was also observed in the tracheae of the vascular bundle of the style. These results indicate that a calcium gradient exists in the lettuce style, and that pollination induces an increase in stylar calcium levels.

Wind-induced mechanical stimulation and water shortage are important stresses in arid/ semiarid regions. However, little is known about the combined effects of mechanical stimulation and water availability. Since the effects of high water availability on biomass and allocation are opposite to those from mechanical stimulation, it is hypothesized that high water availability suppresses the effects of mechanical stimulation. To test this hypothesis, seedlings of Lolium perenne were subjected to two levels of brushing (non-brushing versus brushing 60 seconds d^-1) and two levels of water availability (200 ml d^-1 versus 400 ml d^-1). Brushing had no effects on the total biomass of L. perenne, indicating that brushing is not a stressful factor. However, brushing significantly decreased plant height and dramatically increased the root/shoot ratio. The differences in biomass allocation between brushed and non-brushed plants at high water availability were significantly smaller than those at low water availability, showing that the effects of brushing are suppressed by high water availability. These results suggest that L. perenne may have evolved some traits to cope with frequent mechanical disturbance.

Tiselius' outstanding collection Potamogetones suecici exsiccati is reviewed and re-evaluated from the viewpoint of the present nomenclature and taxonomy. All 150 gatherings issued in this collection are listed and interpreted taxonomically. In a few cases new taxonomic findings are given based on molecular investigation of plant material from the type localities. All new names proposed in this collection are listed and checked for their nomenclatural validity and legitimacy. Lectotypes are designated for 64 valid names and authentic specimens listed for 27 additional invalid designations. Two names (and their types) are of particular importance for contemporary plant taxonomy because these are the correct names for recognized and confirmed Potamogeton hybrids: P. × torssanderi for the triple hybrid P. gramineus × P. lucens × P. perfoliatus and P. × lanceolatifolius for P. gramineus × P. nodosus.

Photinia sorbifolia W.B. Liao & W. Guo sp. nova (Rosaceae) from Hunan Province, China, is described and illustrated. Its relationships with two morphologically close species P. schneideriana and P. villosa are discussed. The persistent, densely tomentose leaves with eight to fourteen pairs of secondary veins of P. sorbifolia distinguish it from P. schneideriana, which has sparsely tomentose leaves, and from P. villosa, with initially villous, then glabrous leaves; in the latter two species, the leaves have ten to fifteen and five to seven pairs of secondary veins, respectively. Both P. sorbifolia and P. schneideriana have compound inflorescences, while P. villosa has a simple corymb inflorescence.

Two new species, Rhododendron pudiense Xiang Chen & Jiayong Huang and R. jiulongshanense Xiang Chen & Jiayong Huang, and one new variety, R. delavayi var. adenostylum Xiang Chen & X. Chen (Ericaceae), from Guizhou Province, China are described and illustrated. Rhododendron pudiense is close to R. paradoxum and R. denudatum, from which it differs by having oblanceolate or elliptic leaves with a two-layered indumentum, a more floriferous inflorescence, a glandular and tomentose pedicel and calyx, a pinkish white corolla, fewer stamens, and a densely white shiny pubescent ovary. Rhododendron jiulongshanense differs from the most morphologically similar species R. glanduliferum and R. magniflorum by having usually glabrous branchlets, oblong-elliptic or long obovate leaves, a more floriferous inflorescence, a much smaller calyx, and a mid-sized narrowly tubular-campanulate corolla. Rhododendron delavayi var. adenostylum differs from R. delavayi var. delavayi by having a glandular style.

Hydrocotyle changanensis X.C. Du & Y. Ren sp. nova (Araliaceae) is described from Shaanxi Province, northwestern China. The simple scapes of H. chonganensis have 2–5 layers of flowers in their umbels, different from all other Chinese Hydrocotyle species. It is morphologically similar to H. sibthorpioides, however it differs from the latter by its narrower and longer styles, depressed stylopodia and longer pedicels. We present a key for identification, a line drawing of H. chonganensis and a plate of SEM micrographs of H. changanensis and H. sibthorpioides. We discuss the relationships among H. changanensis and all species currently recognized in this genus in China.