Spiranthes diluvialis (Orchidaceae), a new species from the western United States

Spiranthes diluvialis, a species known from widely scattered localities in the western United States, is formally described. It has been confused in the past with a number of other species. Morphological characters and cytological data indicate an origin through hybridization ofS. magnicamporum andS. romanzoffiana.     

Stomatal opening in isolated epidermis of Commelina benghalensis L. heterophasic response to KCl concentration

The pattern of stomatal opening in epidermal strips detached from leaves of Commelina benghalensis was examined. Two different phases could be distinguished in the stomatal response to KCl, one at low concentrations of KCl (up to 60 mM) and the other at high KCl concentrations (above 100 mM). The stomatal opening at low KCl concentrations was stimulated remarkably by light or fusicoccin and was suppressed by abscisic acid. At higher KCl concentrations, the stimulation by light or FC as well as the inhibition by ABA was limited. Both phases of stomatal response to KCl were sensitive to carbonyl cyanide-m-chlorophenyl hydrazone. The results suggest that illumination or FC favours selectively stomatal opening only at low KCl concentrations. The ionic participation in the stomatal opening is similar to the heterophasic uptake of ions by plant cells/roots.Abbreviations FC fusicoccin - ABA abscisic acid - CCCP carbonyl cyanide-m-chlorophenyl hydrazone     

Reproductive effort and sex allocation strategy in Commelina benghalensis L., a common monsoon weed

Commelina benghalensis L. exhibits variability in both foliar and floral features; every plant bears three types of branches and four types of flowers. The branches are negatively geotropic, positively geotropic and diageotropic. The flowers are uni- or bisexual, chasmogamous and cleistogamous. This variability influences the breeding system as well as resource allocation to male and female functions. The plants allocate c. 15% of their total resources to reproduction, the major part of which (68.9%) is devoted to production of aerial branches. The proportion of reproductive effort (RE) allocated to various branch systems is correlated with the availability of resources at the time of their differentiation. The pollen/ovule (P/O) ratio, female : male biomass ratio and reproductive output vary between different flower and branch types; variation is more pronounced in the latter. These variations notwithstanding, the results are in line with Charnov's sex allocation theory. The cleistogamous flowers of aerial branches are, however, an exception, being male- rather than female-biased. The reason behind the deviation is, in all probability, their recent evolution from chasmogamous flowers.  © 2002 The Linnean Society of London, Botanical Journal of the Linnean Society , 2002, 140 , 403−413.     

Parmelia pustulifera,a new lichen from southeastern United States

A new species inParmelia subgenusParmelia sect.Hypotrachyna,P. pustulifera, is described from southeastern United States. It is similar in chemistry and fine structure of the cortex toP. livida Taylor and in gross morphology toP. formosana Zahlbr.     

Tricharia vezdae (Ascomycetes: Asterothyriaceae), a new lichen species from the southeastern United States

Tricharia vezdae is described as new from specimens collected in Tennessee, Louisiana and Florida. It is characterized by a corticolous habit, the presence of only a few sterile hairs, the unusual structure of the conidia-like hyphae on the hyphophores and of the ascospores.

     

Investigation ofJuniperus species of the United States for new Sources of Cedarwood Oil

Economic Botany - The 11 taxa of Juniperus with widespread distribution in the United States and with significant biomass production were investigated to determine their yields of cedarwood oil and...     

Two new species of Gomphidius from the Western United States and Eastern Siberia

Study of the genus Gomphidius from recent material from Asia and North America has been carried out using traditional taxonomy combined with molecular systematics. Two new species of Gomphidius (G. borealis and G. pseudoflavipes) are described, one from Eastern Siberia and a second from rarely collected habitats in the Western United States. One taxon has the longest spores reported for the genus and the second species appears to be associated with a Siberian larch.     

Phytophthora irrigata, a new species isolated from irrigation reservoirs and rivers in Eastern United States of America

A new species of Phytophthora, previously referred to as the 'Dre I' taxon, is named Phytophthora irrigata. Isolates of P. irrigata morphologically and physiologically resemble Phytophthora drechsleri. They are heterothallic, produce nonpapillate sporangia, and grow well at 35 degrees C. The above two species differ significantly in uniformity of mycelium, presence of chlamydospores, DNA fingerprint, and sequences of multiple nuclear and mtDNA regions. Phytophthora irrigata produces smaller sporangia and a distinct DNA fingerprint. Sequence alignments in the ribosomal DNA internal transcribed spacer regions place Phytophthora fallax and Phytophthora captisoa as its closest relatives. The optimal temperature for culture growth is above 30 degrees C and the maximum temperature is 40 degrees C. This new species is abundant in irrigation reservoirs and natural waterways in Virginia and was also isolated in Pennsylvania.     

美国对入侵种的管理对策

外来种入侵是产生当前世界生物多样性危机的重要原因之一。目前外来种入侵问题已经引起人们的普遍关注。1999年2月美国联邦政府发布总统令,号召联邦政府机构执行人员防止外来入侵种所造成的严重环境威胁,指示有关职能部门行使职权阻止引入入侵种并且恢复本地种。总统令指示建立一个入侵物种理事会,并就理事会、联邦机构的职责做了相应界定。美国农业部等部门支持的入侵植物管理国家策略项目,提出了针对入侵种的三项国家目标一入侵种的预防、控制和本地种的恢复。国家管理策略的制定不同层次的人们提供了合作、教育和研究的机遇。美国政府部门以及有关社会团体已经就外来种入侵危害防范积极展开行动,包括制定标准防止入侵种进入,控制、根除入侵种,向民众进行有关外来种入侵的教育,增加财政年度预算等等。     

Two new species of Diaphanosoma Fischer, 1850(Crustacea: Branchiopoda: Cladocera) from the United States

Two new species of the genus Diaphanosoma, D. oligosetum and D. dorotheae, from Louisiana and North Carolina respectively, are described. The former species has large head with protruding dorsal part, large lanceolate spine on the basipodite's distal outer end, an extremely reduced number of antennal setae, up to six in adult specimens, and unique armament of valve margin. On the whole, it shows the pronounced combination of primitive and specialized morphological traits. D. dorotheae is a member of D. brachyurum species group differing from its other known representatives in presence of a small but very conspicuous spine on the end of proximal segment of antennal exopodite and a variable number of setae (seven or eight) on the distal segment of the branch. (© 2005 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)     

Description of two new species of Clivina Latreille (Coleoptera, Carabidae, Clivinini) from southeastern United States

Two new species of the genus Clivina Latreille are described. One, Clivina choatei Bousquet & Skelley, belongs to the nominotypical subgenus and is known from six specimens collected in northern Florida. The species is structurally similar to Clivina myops Bousquet, known only from the holotype found in North Carolina, but differs among others by its smaller size and wider elytral striae. The second species, Clivina alabama Bousquet, belongs to the subgenus Antroforceps Barr and is known from two specimens collected in north-central Alabama. The species is structurally most similar to Clivina sasajii Ball, known only from Latimer County in Oklahoma, but differs among others in the absence of eyes and in having the pronotum and elytra proportionally wider.     

饭包草种子萌发过程中养分运输和 消耗的细胞学过程初探

对饭包草大粒种子萌发过程中胚结构变化、养分运输和肖耗的细胞学过程进行了观察.结果显示:种子萌发时萌发孔盖张开,胚根、胚芽、胚轴、子叶鞘和子叶柄突破种皮生长,子叶片呈球状留在胚乳内吸收营养;透射电镜观察显示胚乳养分运输主要通过传递细胞运输、穿壁运输、胞间通道运输三种方式;细胞内养分消耗过程是细胞程序性死亡的过程,多膜小体...     

Two new species of the pinnate microsporophyll Pramelreuthia from the upper Triassic of the southwestern United States

Two new species of the enigmatic gymnosperm microsporophyll Pramelreuthia, found in the Upper Triassic Chinle Formation at five localities in the southwestern United States, provide significant new evidence on key morphological characters of the genus and extend its known geographical range. These new fossils also demonstrate that the genus was polytypic and reveal the plant megafossil sources for several common and geographically widespread dispersed Upper Triassic microfossil taxa. The genus Pramelreuthia, which until this study was known only from a single specimen from the Upper Triassic of Austria, is a planar pinnate structure consisting of a slender naked axis bearing stalked synangia in opposite to subopposite pairs. Synangia of all three species of Pramelreuthia are oval to subrectangular in lateral view and are composed of two adpressed flattened valves each of which contains up to 20 or more elongate, subcylindrical, tapered sporangia that bear nonstriate bisaccate pollen. Pramelreuthia yazzi sp. nov. is slightly smaller than the type species P. haberfelneri, and its synangia contain pollen generally similar in morphology and size to several species of the dispersed pollen taxon Pityosporites, including P. chinleana, P. oldhamensis, and P. devolvens. Pramelreuthia dubielii sp. nov. is much larger than the other two species; its synangia contain pollen similar to the dispersed pollen species Protodiploxypinus americus.