Volatile leaf oil diversity in the narrow range endemic Eucalyptus argutifolia (Myrtaceae) and its widespread congener Eucalyptus obtusiflora

Variation in the qualitative composition of volatile leaf oil was examined in the rare Eucalyptus argutifolia and its widespread congener Eucalyptus obtusiflora . The results revealed that, consistent with the pattern seen with allozymes, E. argutifolia had less variation within populations than E. obtusiflora . Total leaf oil diversity was also significantly lower in the rare species. As found with allozymes, most leaf oil diversity was within populations, but there was also a significant proportion of the variation between populations (25.2% and 27.3% for E. argutifolia and E. obtusiflora , respectively). There were significant associations between phenotypic distance based on leaf oils and geographical distance and between phenotypic and genetic distance across all populations, but these associations were not evident within species. Factors leading to reduced variation in E. argutifolia appear to affect all types of variation, but the relationships between different types of variation within the species are less apparent.  © 2009 The Linnean Society of London, Biological Journal of the Linnean Society , 2009, 96 , 738–745.     

Comparison of genetic diversity between narrowly endemic shrub Menziesia goyozanensis and its widespread congener M. pentandra (Ericaceae)

Menziesia goyozanensis, a Japanese kindof fool's huckleberry, is a shrub speciesendemic only to Mt. Goyo in northern Japan.This species is listed as `criticallyendangered' in the Red Data Book of wild plantsin Japan, and only a single population has yetbeen discovered. The allozyme diversity andRAPD variation of Menziesia pentandrawere eight- and threefold greater than those ofM. goyozanensis, respectively, althoughwe examined only five populations representinga part of the distribution of M.pentandra. Because the environment surroundingthe population of M. goyoznaensis seemsto be stable at present, it is not necessary toplan an urgent ecological conservation practicefor the species. However, considering that thehabitat of M. goyozanensis is very smalland large vegetative disturbances occasionallyoccur in cool temperate forests, in which thespecies dwells, ex situ conservation isessential.     

Demonstration of pollinator‐mediated competition between two native Impatiens species,Impatiens noli‐tangere and I. textori (Balsaminaceae)

Plant–plant interspecific competition via pollinators occurs when the flowering seasons of two or more plant species overlap and the pollinator fauna is shared. Negative sexual interactions between species (reproductive interference) through improper heterospecific pollen transfer have recently been reported between native and invasive species demonstrating pollination‐driven competition. We focused on two native Impatiens species (I. noli‐tangere and I. textori) found in Japan and examined whether pollinator‐mediated plant competition occurs between them. We demonstrate that I. noli‐tangere and I. textori share the same pollination niche (i.e., flowering season, pollinator fauna, and position of pollen on the pollinator's body). In addition, heterospecific pollen grains were deposited on most stigmas of both I. noli‐tangere and I. textori flowers that were situated within 2 m of flowers of the other species resulting in depressed fruit set. Further, by hand‐pollination experiments, we show that when as few as 10% of the pollen grains are heterospecific, fruit set is decreased to less than half in both species. These results show that intensive pollinator‐mediated competition occurs between I. noli‐tangere and I. textori. This study suggests that intensive pollinator‐mediated competition occurs in the wild even when interacting species are both native and not invasive.     

The role of autonomous self-pollination in floral longevity in varieties of Impatiens hypophylla (Balsaminaceae)

The floral longevity of unpollinated, hand self-, and hand cross-pollinated flowers was compared in two varieties of Impatiens hypophylla, which contrasts with their mating systems. When flowers were emasculated and hand-pollinated every day after anthesis, their longevity was reduced. In the absence of emasculation and hand pollination, the staminate phase of the flowers of both varieties was 1 d longer. After the staminate phase, flowers of the outcrossing variety dropped their androecium, exposing the stigma and initiating the pistillate phase, which lasted for ～2 d. In contrast, flowers of the mixed-mating variety self-pollinated autonomously and then terminated their flowering. Under great seasonal variation in the pollinator visitation rate, which was observed in their natural populations, the outcrossing variety should maximize expected outcross success through the phenology of floral sex phases, whereas the mixed-mating variety self-pollinated ovules that were not outcrossed within the staminate phase. Based on these results, I suggest that the autonomous self-pollination in I. hypophylla induced differences both in the selfing coefficient and in floral longevity between the varieties.     

Trade-offs between flower number and investment to a flower in selfing and outcrossing varieties of Impatiens hypophylla (Balsaminaceae)

Floral resource allocation was compared on a whole-plant basis between two varieties of Impatiens hypophylla that differ in flower size. There were significant negative correlations between flower number and investments to a flower at both the within-population and between-variety levels. In individual flowers, var. hypophylla with larger flowers invested significantly more resources to male and pollinator-attractive functions, whereas investments to female function did not differ between the varieties. In experimental populations placed in the field, pollinators preferred the larger flowers of var. hypophylla even within the same habitat of var. microhypophylla, which has smaller flowers. There was a significant lack of observed heterozygosity only in var. microhypophylla. Thus, the outcrossing variety had more attractive but fewer flowers, while the selfing variety had less attractive but more abundant flowers.     

Pollination ecology and pollination system of Impatiens reptans (Balsaminaceae) endemic to China

BACKGROUND AND AIMS: China is one of the centres of geographical distribution of Impatiens L. Studies of the pollination ecology of this genus in China have, until now, been unreported. Impatiens reptans, a species endemic to China, was studied. The aims were to examine the pollination ecology and pollination system of this species, to compare its pollination ecology with other Impatiens species growing in Sumatra and Japan, and to discuss possible reasons for its limited distribution. METHODS: The pollination ecology of I. reptans was studied by carrying out continuous observations within three naturally growing populations. Its pollination system was studied using different pollination methods, marking and counting pollen grains, assessing pollen viability and observing pollinator behaviour. KEY RESULTS: The flowering phase of the protandrous I. reptans lasted for 89 d. The life span of an individual flower was 3.6 d. Primary pollinators were honey-bees and bumble-bees. Secondary pollinators were diurnal hawk moths and butterflies. Bombus briviceps and Bombus sp. were nectar gatherers. The mean nectar sugar concentration was 29.5 %, and the mean value of sucrose/glucose + fructose was 0.82. The proportion of seed set ranged from 0.857 to 0.873. Distances that seeds were ejected ranged from 0.58 to 1.17 m. Percentage seed germination under controlled conditions was 23.1. Pollen viability was highest on the day of anthesis and thereafter decreased. Ratios of pollen : ovules ranged from 958.8 to 970.6. CONCLUSIONS: Impatiens reptans reproduces by means of cross-pollination. Its dependence on a specialized habitat, a narrow environmental niche, a low percentage of seed germination, and habitat loss could be reasons for its limited distribution and endemism.     

中国四川凤仙花属 一新种——凉山凤仙花

描述了四川凤仙花属一新种,凉山凤仙花。新种与黄麻叶凤仙花近缘,主要区别:花序2~6花,均垂于叶片下,囊状的唇瓣肿胀,在中部明显弯曲,翼瓣基部裂片先端长渐尖或尾尖,上部裂片背腹约120°~180°扭转。     

Patterns of genetic diversity in the rare Erigeron lemmoni and comparison with its more widespread congener,Erigeron arisolius (Asteraceae)

Analysis of levels and patterns of genetic variation in a rare species is important for determining whether genetic factors associated with small population size, such as genetic drift or inbreeding, may be negatively affecting a species. In this study, we compared estimates of genetic diversity and patterns of population genetic structure in a rare cliff endemic, Erigeron lemmonii, to those of a widespread congener, E. arisolius. Our goals were to assess whether rarity and small population size have negatively affected levels of genetic diversity in E. lemmonii and to identify genetic threats that may limit the ability of E. lemmonii to persist. Levels of observed and expected heterozygosity and allelic richness in E. lemmonii were approximately 60 % of those found in E. arisolius. After correcting for null alleles, inbreeding coefficients in both species of Erigeron were very small, suggesting that both species are highly outcrossing and may demonstrate self-incompatibility. Patterns of genetic structure in both species revealed almost no population substructuring, indicating that widespread gene flow is occurring within each species. Because we found no evidence for inbreeding or a genetic bottleneck in E. lemmonii, it is likely that the species’ lower genetic diversity may be the result of genetic drift. Because E. lemmoni exists in a single population, no other populations exist to bolster population size or genetic diversity in the event of declines; thus, conservation efforts should focus on seed collection from as many individuals as possible to protect against possible future losses of genetic diversity. We also recommend continued monitoring of both population size and genetic diversity in E. lemmonii to ensure the species’ long-term persistence and viability.     

Genetic diversity and structure of the narrow endemic Wyethia reticulata and its congener W. bolanderi (Asteraceae) using RAPD and allozyme techniques

Wyethia reticulata is an edaphic endemic in the Sierra Nevada foothills. Its sympatric congener, W. bolanderi, is also restricted to the foothills, but has a north-south range of 275 km, compared to 14 km for W. reticulata. The goals of this study were to determine clonal diversity, population size, genetic variation, and spatial and generic structure for each species from paired populations in El Dorado County, California, using allozyme and RAPD (random amplified polymorphic DNA) methodologies. Wyethia reticulata, spreading by rhizomes, had populations dominated by a few large individuals, while W. bolanderi, with a basal caudex, had populations of a few hundred evenly sized individuals. Genetic analyses indicated that W. reticulata, compared to its congener, had somewhat less genetic diversity (H(T): 0.28 vs. 0.38), had more of its genetic variation partitioned among populations (F(ST): 0.25 vs. 0.07), and showed a complete absence of inbreeding (F(IS): -0.03 vs. 0.22). Population membership in accord with populations defined by geographical location resulted only when all markers were included in the analysis. Ecological limits on recruitment of genets appears to result in small population size in W. reticulata. Limited gene flow, drift within small populations, and sexual reproductive dominance of large clones result in the genetic divergence of populations in this species, while genetic diversity is maintained by the longevity of clones and outbreeding.     

Impatiens maculifera sp. nov. (Balsaminaceae) Yunnan,China

Impatiens (Balsaminaceae) is a notoriously difficult genus to study for reasons that include small, remote and endemic areas of occurrence, and difficulty in obtaining well‐dried herbarium specimens and separating and reconstructing floral parts from available dried specimens. Impatiens has also been notoriously difficult when it comes to phylogenetic resolution at the infrageneric level, but a new system with two subgenera (Impatiens and Clavicarpa) was recently proposed by Yu et al. and it has made it easier to classify newly discovered species. Impatiens maculifera, a new species of Balsaminaceae from Malipo County, Yunnan, China described here, is similar to I. parvisepala S.X. Yu & Y.T. Hou in having racemose inflorescences, four lateral sepals, clavate capsules and ellipsoid seeds, but differs in having leaves narrowly oval or with elliptic–lanceolate blades (versus obovate or obovate–lanceolate), obvious petioles (versus leaves subsessile), racemose inflorescence with 8–12 flowers (versus 6–8 flowers), flowers greenish yellow (versus yellow), lateral united petals and lower sepal with dense red spots (versus red spots absent), and dorsal petal with apparent stalk at base (versus unapparent stalk). Morphological characters and molecular phylogenetic analyses of DNA sequences from both nuclear ribosomal and plastid genes show that the new species differs distinctively from I. parvisepala. Furthermore, I. maculifera is distinguished from other Impatiens species based on morphological, micromorphological and palynological evidence, and molecular data.     

Impatiens shimianensis sp. nov. (Balsaminaceae) from Sichuan,China

Impatiens shimianensis Q. Luo (Balsaminaceae), a new species from Shimian county in southwestern Sichuan province, China, is reported and its morphological characteristics are described and illustrated. Pollen grain morphology and seeds under SEM are also described. The new species is somewhat similar to I. bahanensis, I. brachycentra, I. laxiflora, I. parviflora and I. racemosa, but differs mainly by having leaf blades with white short stiff adpressed hairs; basal lobes of lateral united petals triangular, distal lobes lanceolate; and lower sepal salver‐shaped. The distinguishing characters for these six Impatiens species are given in a table.     

Impatiens nanlingensis sp. nov. (Balsaminaceae) from Guangdong,China

Impatiens nanlingensis A. Q. Dong & F. W. Xing, a new species of Impatiens (Balsaminaceae) from Guangdong, China, is described and illustrated. It is morphologically similar to I. jinggangensis Y. L. Chen, but differs mainly by its lateral united petals; basal lobes suborbicular, marked with yellow stripes; distal lobes narrowly caudate, apex tailed. It also resembles I. bicornuta, but I. bicornuta differs mainly in its longer peduncles, up to 25 cm, pale blue–purple flowers and broadly sigmoid‐curved–saccate lower sepal.     

Impatiens quadriloba sp. nov. (Balsaminaceae) from Sichuan,China

Impatiens quadriloba K. M. Liu et Y. L. Xiang sp. nov. collected from the Siguniang Mountains Nature Reserve in northwestern Sichuan, China, is described and illustrated. The seed‐coat and pollen morphology of the new species are described and diagnostic morphological characters that distinguish the new species from the related I. falcifer Hook. f. are discussed.     

Impatiens pterocaulis sp. nov. (Balsaminaceae) from Guangxi,China

Impatiens pterocaulis S. X. Yu et L. R. Zhang, a new species of the Balsaminaceae from Yancha, Longlin, Guangxi Region, is described and illustrated. This species is similar to I. wilsonii in having nearly white flowers, 4 lateral sepals and a racememos inflorescence, but differs by having winged stems, very short‐spurred lower sepal, yellowish flowers and an acuminate dorsal petal apex. Pollen characters and leaf epidermal micro‐characters of these two species were studied, and the results support that the two species should be kept separate.     

Impatiens liboensis sp. nov. (Balsaminaceae) from Guizhou,China

Impatiens liboensis K. M. Liu & R. P. Kuang, a new species collected from Xiaoqikong Scenic Area in southern Guizhou, China, is described and illustrated, including its seed and pollen micro‐morphology. Impatiens liboensis is similar to I. chishuiensis Y. X. Xiong and I. tubulosa Hemsl., but differs by having obviously irregular underground tubers, white or pink–white flowers, lower sepal with a 1.2–1.5 cm long spur, obovate dorsal petal, and obovate‐oblong or obliquely obovate lower lobes of the lateral petals with retuse apex.     

Impatiens chashanensis (Balsaminaceae) sp. nov. from Sichuan, China

Impatiens chashanensis H. Y. Bi & S. X. Yu (Balsaminaceae), a new species from the Sichuan Province in China, is described and illustrated. In comparison with the morphologically close I. dicentra , both species have succulent stems and the lobes of the lateral united petals end in a long hair, but I. chashanensis differs in having white flowers, four lateral sepals, lacerate apex of the inner sepal, shorter spur with swollen, slightly bifid apices. Moreover, leaf epidermal characters also support the recognition of the new species.     

Impatiens menghuochengensis sp. nov. (Balsaminaceae) from Sichuan,China

Impatiens menghuochengensis Q Luo. (Balsaminaceae), a new species from Shimian county in southwestern Sichuan province, China, is described and illustrated. It is similar to I. tortisepala J. D. Hooker, but differs in having stem unbranched in lower portion; lateral sepals transparent, obliquely ovate; dorsal petal with central columnar cristate swelling; lateral united petals with distal lobes oblong‐dolabriform, apically retuse; lower sepal saccate with purple–red veins, abruptly narrowed at belly into an incurved spur 20–25 mm. The morphological characteristics and surface patterning of the seeds and pollen of the new species are examined under SEM and compared with those of I. tortisepala.     

Gene flow between Impatiens radicans and I. javensis (Balsaminaceae) in Gunung Pangrango, central Java, Indonesia

This study reports the natural hybridization of two species of Impatiens in the mountain forests of Gunung Gede-Pangrango, in central Java, Indonesia. Impatiens radicans, which inhabits the highest altitude zone in the mountains of this park, and I. javensis, which inhabits a zone of lower altitude, can be easily distinguished by their morphological features. However, some populations that inhabit regions between the two zones have characteristics that appear to be combinations of traits of I. radicans and I. javensis. Sequence analysis of the 800-bp nuclear ITS region and 449-bp plastid trnL-F locus demonstrated that hybridization between the two species has occurred, and suggests gene flow between the species.     

Phenotypic selection in a natural population of Impatiens pallida Nutt. (Balsaminaceae)

In the annual plant Impatiens pallida, individuals exhibit a floral heteromorphism consisting of autogamously selfing, cleistogamous (CL) flowers and partially outcrossing, chasmogamous (CH) flowers. As part of an investigation into natural selection and mating system evolution in I. pallida, we measured the magnitude and direction of phenotypic selection on nine life history characters (two traits measured on three dates, one measured on two dates and one measured once). Three of these characters were positively correlated with the ratio of CH/CL flowers produced per plant, which is an important determinant of the mating system. Values for the nine characters and three different measures of fitness (viability, fecundity, lifetime) were estimated for 500 plants in five locations over a single growing season. Based on lifetime fitness, linear selection differentials were significant for all nine characters, indicating a selective advantage to tall, leafy, highly branched plants that flowered early. However, only two of these characters had a direct effect on fitness. Selection was significant on all nine characters when based on fecundity as well as lifetime fitness; however, only three of five characters examined had significant selection based on viability fitness. For all fitness components, the frequency of significant linear and nonlinear selection coefficients was comparable (23% vs 17% of all cases, respectively), but nonlinear coefficients were generally larger. Finally, the magnitude and direction of direct linear selection was heterogeneous among locations, for all characters and all fitness components. Collectively these results suggest that selection is strong, favouring large size, high allocation to reproduction and high CH/CL flower ratios. However, any directional evolutionary changes in vegetative or reproductive characters may be constrained by strong non-linear and correlational selection.