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1.
Hans-Joachim Esser 《Brittonia》1999,51(2):170-180
The new genusRhodothyrsus is proposed, based on the AmazonianSenefeldera macrophylla Ducke but also containing another newly described species,Rhodothyrsus hirsutus from northwestern Venezuela. The genus is a member of the tribe Hippomaneae of the Euphorbiaceae and apparently related toSenefeldera, but its closest relationships are still obscure, because the phylogeny of the tribe is poorly known and most of the significant
characters ofRhodothyrsus are probably autapomorphies or symplesiomorphies. The restriction to tropical lowland rain forests is rare within the Hippomaneae,
and several floral characters, pointing to a specialized pollination possibly by butterflies, are unique in the tribe. 相似文献
2.
Thomas Mione 《Brittonia》1999,51(1):31-33
The following species, originally described in the genusSaracha Ruiz & Pav., are transferred toJaltomata, in accordance with contemporary generic boundaries.Jaltomata auriculata (Miers) Mione is distributed from Venezuela to Peru;J. contorta (Ruiz & Pav.) Mione andJ. diversa (J. F. Macbr.) Mione both occur in Peru;J. herrerae (C. V. Morton) Mione is distributed in Peru and Bolivia;J. nitida (Bitter) Mione occurs in Venezuela. 相似文献
3.
We report here the results of an 8-year study of the growth and population dynamics of Quercus mongolica ssp. crispula in a Pinus densiflora stand in a state of succession. In 1998, there were 169 Q. mongolica ssp. crispula individuals in a 400-m2 plot under the P. densiflora canopy. This number remained nearly constant between 1998 and 2005. Mean recruitment of new individuals was 11 year−1, while mean mortality was 12 year−1. Of the 35 individuals ≥60 cm in height existing in 1998, 30 were still surviving in 2005. We were able to represent the
height growth of Q. mongolica ssp. crispula individuals as H=30 [1+21.96 exp(−0.0839t)]−1, with t = years since 1998 and H = height in meters. Using this equation we predict that by 2015 the mean height of Q. mongolica ssp. crispula trees in the stand will exceed those of understory trees, such as Rhus trichocarpa and Prunus
maximowiczii. Once above the understory stratum, the Q. mongolica ssp. crispula trees can be expected to grow more rapidly due to the better light conditions, thereby rapidly reaching the canopy stratum
of the P. densiflora stand. 相似文献
4.
Summary The Brazilian genus Cenostigma Tul. (Leguminosae – Caesalpinioideae) is revised and now comprises two species: C. macrophyllum Tul. and C. tocantinum Ducke. 相似文献
5.
Takashi Saitoh Jun Osawa Toshikazu Takanishi Shintaro Hayakashi Masaaki Ohmori Toshio Morita Shigeru Uemura Jon Olav Vik Nils Chr. Stenseth Koji Maekawa 《Population Ecology》2007,49(3):249-256
The effects of the abundance of acorns of the oak, Quercus crispula, on the population dynamics of three rodent species (Apodemus speciosus, A. argenteus, and Clethrionomys rufocanus) were analyzed using time series data (1992–2006). The data were obtained in a forest in northern Hokkaido, Japan, by live
trapping rodents and directly counting acorns on the ground. Apodemus speciosus generally increased in abundance following acorn masting. However, the clear effect of acorn abundance was not detected for
the other two rodent species. Acorns of Q. crispula contain tannins, which potentially have detrimental effects on herbivores. Apodemus speciosus may reduce the damage caused by acorn tannins with tannin-binding salivary proteins and tannase-producing bacteria, whereas
such physiological tolerance to tannins is not known in the other two rodent species. The differences in the effects of acorns
between the three species may be due to differences in their physiological tolerance to tannins. 相似文献
6.
Yukari Mizuta 《Mycoscience》2006,47(6):380-384
Two new species and one new variety of Oudemansiella (Agaricales) from Japan are described and illustrated: (1) Oudemansiella latilamellata sp. nov. (subgenus Xerula, section Radicatae) has relatively broad lamellae and broadly ellipsoid spores with a subacute apex; (2) Oudemansiella rhodophylla sp. nov. (subgenus Xerula, section Radicatae), growing in deciduous forests of Fagus crenata, Quercus crispula, etc., is characteristic in having lamellae tinted reddish; and (3) Oudemansiella amygdaliformis var. bispora var. nov. (subgenus Xerula, section Albotomentosae) is distinguished from the type variety by having two-spored basidia and grows in evergreen oak forests (Castanopsis sieboldii, Quercus glauca, etc.) or bamboo groves. 相似文献
7.
Summary Two new species of Rhynchospora, R. acanthoma and R. rupestris, are described and illustrated. Their geographical distributions are discussed. The status of R. exilis and its synonymy is clarified. 相似文献
8.
Summary The crown light environments of saplings of two Costa Rican rain forest tree species were simultaneously compared. The species, Dipteryx panamensis (Pitt.) Record & Mell., a relatively shade-intolerant species, and Lecythis ampla Miers, a shade-tolerant species, have contrasting growth and branching patterns. Quantum sensors were placed throughout the crowns of saplings up to 2.5 m tall and quantum fluxes were recorded with microloggers for seven-day periods. The shade-intolerant species had total quantum flux densities 35% larger than those of the shade-tolerant species, but totals for both species were less than 2% of full sun. More than 90% of the quantum flux densities measured within the crowns of both species were less than 25 mol m-2s-1. Lateral light was an important component of daily quantum flux totals; for saplings of both species, the half-hour with the maximum average irradiance for the day frequently occurred in mid-morning or midafternoon. Despite dissimilar crown and leaf display, there was no difference in the overall variability of irradiance within the crowns of the two species. However, quantum fluxes received within the crowns differed substantially in both species. Within-crown locations differed significantly from day to day because of variation in weather conditions. Daily total quantum flux densities and totals expressed as a percent of full sun were significantly correlated with height growth over the previous 12 months. 相似文献
9.
We studied the autumn food habits of the Asiatic black bear (Ursus thibetanus) from 1993 to 1997, based on 202 fecal samples in the Chichibu Mountains, central Japan. Nuts occupied the highest proportions of autumn foods (59.9–85.8% important values). Although the proportion of nuts of Quercus crispula, Fagus crenata and Fagus japonica varied greatly between the years, acorns of Q.crispula were most prevalent in four of the five years. We also determined the relative nut production of these three species by counting the number of nuts or cupules on the ground. Black bears consumed the nuts according to their relative availabilities. Nuts of Q.crispula appeared to be the most important food because: (i) these nuts were eaten in the highest proportion in four of the five study years; and (ii) even in poor years the bears consumed acorns of Q.crispula, whereas nuts of Fagus spp. were not consumed. We discuss the significance of alternative foods for black bears in relation to food tree diversity in the forest and the necessity for long-term studies examining the food habits of Asiatic black bears. 相似文献
10.
11.
Evaluation of the potential role of water in spread of conidia of the Neotyphodium endophyte of Poa ampla 总被引:1,自引:0,他引:1
Mariusz Tadych Marshall Bergen Frank M. Dugan James F. White Jr. 《Mycological Research》2007,111(4):466-472
Neotyphodium endophytes are asexual, filamentous fungi, mutualistically associated with diverse cool season grasses. Infected seeds and vegetative organs of infected host plants are the only known modes of propagation of the asexual endophytes. In the last decade certain Epichloë and Neotyphodium-infected grass species have been shown to have epiphyllous structures of the endophytes, hyphae, conidiophores, and conidia, growing on leaf blades. The production of epiphyllous conidia suggests the possibility that some of these endophytes may have the ability for plant-to-plant spread. The objective of this study was to determine the possible mechanisms involved in liberation and dispersal of asexual spores of Neotyphodium growing in vitro and epiphyllously on leaves of Poa ampla. Our results indicate that water dispersal is the most likely means of dissemination of conidia of the Neotyphodium sp. Wind generated by dry compressed air does not dislodge the conidia from slide cultures or from P. ampla leaves. 相似文献
12.
Remarks on mixotrophic and autotrophic carbon nutrition of Vitis plantlets cultured in vitro 总被引:1,自引:0,他引:1
Two Vitis species were cultured in vitro under photoautrophic (sucrose-free culture medium) and photomixotrophic (sucrose 15 g l-1) conditions during the period following microcutting rooting (day 34 to day 120). Several parameters were measured at the end of the culture: growth, plant dry weight, carbohydrate uptake from the medium and rates of photosynthesis and dark respiration. The two species behaved very differently. Under photoautotrophic conditions, dark respiration, net photosynthesis and daily CO2 fixation were higher in Vitis vinifera than in Vitis rupestris. Culture under mixotrophic conditions caused increase in growth, respiration and photosynthesis in Vitis rupestris. In contrast, photosynthesis decreased in Vitis vinifera under the same conditions. 相似文献
13.
Thomas G. Lammers 《Brittonia》1998,50(2):233-262
Burmeistera, Centropogon, and Siphocampylus together comprise more than 500 species endemic to the Neotropics, Current knowledge of these genera is unsatisfactory, with
much diversity yet to be described. Over the past seven years, one out of every 28 specimens received for identification has
represented a new species, many characterized by unique or unusual character states. Siphocampylus smilax (Bolivia) is unique in the genus in its parallelodromous leaf venation and extra-floral nectaries. Centropogon dianae (Peru) cannot be accommodated in any recognized infrageneric taxon, and a new section, Centropogon sect. Niveopsis, is proposed for it. The flowers of C. steinii (Ecuador) are the smallest known in the genus, while C. connatilobatus (Venezuela) is the first species to combine arbusculiform pubescence and connate calyx lobes. Burmeistera venezuelensis is only the second species of the genus known to occur in Venezuela and the first to be endemic; similarly, Centropogon wilburii is only the third species of Centropogon known from Mexico and the first to be endemic to that country. Additional novelties are also described. 相似文献
14.
15.
Resprouting ability of<Emphasis Type="Italic"> Quercus crispula</Emphasis> seedlings depends on the vegetation cover of their microhabitats 总被引:5,自引:0,他引:5
To examine the effects of vegetation cover on the resprouting abilities of Quercus crispula seedlings, in each of three consecutive years, we artificially clipped seedlings growing in microhabitats with differing
degrees of vegetation cover. We also investigated the relationship between the level of total nonstructural carbohydrate (TNC)
and resprouting ability. Seedlings with clipped shoots in gaps produced larger resprouting shoots than those in the understory.
Moreover, both the percentage of resprouting seedlings and the survival ratio in seedlings with clipped shoots were negatively
correlated with the degree of vegetation cover. Seedlings stored high levels of TNC, especially in their roots, and their
TNC levels were negatively correlated with the degree of vegetation cover. There were also positive relationships between
the TNC levels in their roots and the degree of resprouting. Hence, we conclude that release from vegetation cover enhanced
the resprouting ability of Q. crispula seedlings by increasing their levels of stored carbohydrate. The key variables affected were the resprouting ratio (the proportion
of seedlings capable of producing new shoots) and the size of the resprouted shoots. 相似文献
16.
This note reports on the presence of a well established population of the isopod Synidotea laevidorsalis (Miers) in the Gironde estuary (southwestern France). This species is new for the European fauna. S. laevidorsalis is a nonendemic cool-temperate to subtropical, shallow-water species which was probably introduced into the study area from
Asia. In the salinity range of 1 to 10 g 1-1 of the Gironde the species constitutes an important component of the brackish-water hyperbenthic community. The population
was already present in 1975 when it was misidentified as the native species Idotea emarginata (Fabricius). 相似文献
17.
Redefinition of the neotropical genus Anthopterus (Ericaceae: Vaccinieae), including one new species
James L. Luteyn 《Brittonia》1996,48(4):605-610
The taxonomic history of Anthopterus as it relates to Themistoclesia is briefly reviewed. Anthopterus is redefined to include several species formerly placed in Themistoclesia. Two subgenera are established within Anthopterus. Anthopterus costaricensis Luteyn is described as new, and the new combination Anthopterus pterotus (A. C. Sm.) Luteyn is made. A key to the genus, a list of the species currently accepted, and brief notes on distribution
and frequency are provided. Most species of Anthopterus are rare and their habitats are endangered. 相似文献
18.
The Frankia strains TtI 11 and TtI 12 isolated from T. trinervis Miers were characterized regarding their carbon source utilization, intrinsic antibiotic resistance, infectivity, and effectivity
on the original host. Both strains grew on BAP medium supplemented with glucose, maltose, and sucrose, but differed in their
ability to use other carbon sources such as propionate, pyruvate, acetate, succinate, citrate, and mannitol.
The isolates were sensitive to five of the twelve antibiotics tested at 1 μg mL−1 concentration: chloramphenicol, tobramycin, eritromycin, streptomycin, and rifampicin. They exhibited a variable degree of
resistance at 1 μg mL−1 concentraction to penicillin G, 4-fluorouracil, oleandomycin, and lincomycin.
Both isolates were able to infect and nodulate the original host plant, and thus represent the first reported infective and
effective microsymbionts for T. trinervis Miers, a rhamnaceous actinorhizal host. R O D Dixon Section editor 相似文献
19.
Recombination rate data are presented for three populations of grape based on framework genetic linkage maps developed with
simple-sequence repeat markers. These linkage maps were constructed from different Vitis species and represent three genetic backgrounds. The first population is pure Vitis vinifera, derived from a cross of the European cultivars Riesling and Cabernet Sauvignon. The second is an interspecific cross between
two commercially used rootstock cultivars of different North American Vitis species parentage, Ramsey (Vitis champinii) and Riparia Gloire (Vitis riparia). The third population, D8909-15 (Vitis rupestris × (Vitis arizonica/Vitis girdiana form)) × F8909-17 (V. rupestris × (V. arizonica/Vitis candicans form)), is an F1 from two half-sibs. Genome-wide and chromosome-wide recombination rates varied across the three populations
and among the six Vitis parents. Global recombination rates in the parents of the third F1 population, with a complex Vitis background, were significantly reduced. In the first and third populations, the recombination rate was significantly greater
in the male parent. Specific genome locations with frequent heterogeneity in recombination were identified, suggesting that
recombination rates are not equal across the Vitis genome. The identification of regions with suppressed or high recombination will aid grape breeders and geneticists who rely
on recombination events to introgress disease resistance genes from the genomes of wild Vitis species, develop fine-scale genetic maps, and clone disease resistance genes.
Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users. 相似文献
20.
Seven new calochroid and fulvoid species of Cortinarius 总被引:1,自引:0,他引:1
We describe seven new European species of Cortinarius. All species are based on analyses of morphological and DNA sequence data. They all belong to a well-supported clade comprising most species traditionally treated in Cortinarius subgenus Phlegmacium sections Fulvi and Calochroi (i.e. the/Calochroi clade). All taxa are either fulvoid (containing anthraquinoid pigments) or calochroid (without these pigments). Morphological and ecological data are presented for all species and compared with similar species. A dichotomous key is presented for C. calochrous and similar species, including all six newly described calochroid species. The calochroid species C. albertii, C. chailluzii, C. cisticola, C. sancti-felicis, C. selandicus and C. vesterholtii spp. nov., and the fulvoid species C. langeorum sp. nov. are described. 相似文献