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1.
To identify characteristics for the selection of Verticillium lecanii isolates with high potential for biocontrol of Sphaerotheca fuliginea under glasshouse conditions, an exploratory study was performed on the effect of water limitation on the development of 14 isolates. The conidial germination, growth and sporulation of isolates of V. lecanii were studied in a tritrophic system on cucumber leaves and in a ditrophic system in Petri dishes. Their mycoparasitic ability was studied in S. fuliginea and Cladosporium cladosporioides . All characteristics were clearly affected by humidity. Four isolates showed good biocontrol potential. The performance of isolates on agar had less predictive value than on powdery mildew. The germination of isolates of V. lecanii was lower and the mycelial growth faster on agar than on mildewed leaves under corresponding humidity conditions. The results suggest that conditions in the phyllosphere differed from the set humidity in the surrounding air. A correlation was found between the lysis of C. cladosporioides growing in dual culture on agar with isolates of V. lecanii and the parasitism of powdery mildew on detached, rooted leaves. C. cladosporioides might offer a suitable substrate for testing isolates of V. lecanii for mycoparasitic potential under various environmental conditions. Conidial germination, growth and sporulation had limited predictive value. 相似文献
2.
M. W. CALLMANDER 《Botanical journal of the Linnean Society. Linnean Society of London》2001,137(4):353-374
This paper provides a taxonomic revision of Pandanus sect. Martellidendron , which so far comprises six species of which only one is known from both staminate and pistillate plants. Research in herbaria and in the field in Madagascar has provided the data on which a revision of the unclear taxonomy of this section can be based. Based on micromorphology, architecture and phytogeography, the number of these dioecious species is reduced. One new species (P. gallinarum Callmander) from the Biosphere reserve of Mananara-North on the east coast is described, and P. karaka Martelli is transferred to this section 30 years after it was assigned to section Dauphinensia. A key to all species of subg. Martellidendron is provided. Finally, the important role of the section for the understanding of the phylogeny of the Pandanaceae is discussed in the context of Indian Ocean biogeography. 相似文献
3.
ILSE BREITWIESER JOSEPHINE M. WARD 《Botanical journal of the Linnean Society. Linnean Society of London》2003,141(2):183-203
Most of the estimated 70–80 species of New Zealand Gnaphalieae are endemic. Those of Anaphalioides , Ewartia , Helichrysum , Leucogenes , Rachelia and Raoulia belong to a putatively monophyletic group which is supported by analysis of nuclear ITS DNA sequences and is virtually confined to New Zealand. All species of Craspedia , Euchiton , Ozothamnus and Pseudognaphalium are excluded from this group. A phylogenetic analysis of 42 species of Gnaphalieae, using 57 morphological, anatomical and palynological characters, was conducted to test the monophyly of this group and to seek evidence of generic relationships. The analysis does not resolve basal relationships among the Gnaphalieae studied here. The putative monophyletic New Zealand group is not retrieved. Monophyly is supported for each of Euchiton , Leucogenes , the whipcord species of Helichrysum , the pulvinate species of Raoulia , and Raoulia subg. Raoulia (excluding the aberrant R. cinerea ), but not for Anaphalioides or Raoulia s.l. There are these two distinct groups in Raoulia s.l. but also a substantial number of isolated species. The sole New Zealand species of Ewartia is not a sister species to Australian Ewartia . The Australian species Ewartia planchonii is the sister species to Euchiton rather than to the other Australian species of Ewartia . © 2003 The Linnean Society of London, Botanical Journal of the Linnean Society , 2003, 141 , 183–203. 相似文献
4.
ARNE PETERS 《Biocontrol Science and Technology》1996,6(3):389-402
The natural host range of entomopathogenic nematodes of the genera Steinernema and Heterorhabditis can be defined as the range of insects which indigenous nematode populations use for propagation. Information on the natural host range is rare. However, based on records of insects found to be naturally infected with nematodes, some conclusions regarding the natural host range of some Steinernema spp. and Heterorhabditis spp. are presented. Reports of indigenous nematode populations impacting on insect populations can be divided between relatively balanced, long-lasting nematode-host associations and unbalanced, short-lasting epizootics. Examples of the augmentation and inoculative introduction of nematodes in agriculture and forestry ecosystems are presented. Based on current knowledge, nematode reproduction strategies are discussed and indications of the risk involved in the release of non-indigenous nematodes are given. 相似文献
5.
E. Vinuela A. Adan G. Smagghe M. Gonzalez Ma. P. Medina F. Budia H. Vogt P. Del Estal 《Biocontrol Science and Technology》2000,10(2):165-177
The effects of azadirachtin on two pests: neonate larvae and newly emerged adults of Ceratitis capitata (Wiedemann) and last instar larvae of Spodoptera exigua (Hubner); and three natural enemies: newly emerged adults of Opius concolor Szepligeti, second instar larvae of Chrysoperla carnea (Stephens), and fifth instar nymphs of Podisus maculiventris (Say) were studied in laboratory. Adult insects were exposed to a non-oil formulation of azadirachtin (Align, emulsifiable concentrate, 3.2% azadirachtin, Sipcam Inagra, Spain) via their drinking water and immature instars were reared in the presence of the insecticide-treated diet. The natural enemies were exposed to at least the maximum field recommended concentration of the insecticide (0.15% v/v). Azadirachtin was highly toxic to neonate larvae of C. capitata and prevented adult emergence at a concentration of 1 mg a.i. l -1 . When adults were fed the insecticide at the maximum recommended concentration, their survival was not affected but egg laying was totally inhibited. Last instar S. exigua larvae were also very susceptible (LC 50 = 7.7 mg a.i. l -1 ) and at a concentration of 10 mg a.i. l -1 fecundity of surviving adults, and egg fertility, were reduced by 72 and 85%, respectively. Effects on O. concolor were large, and significant reductions in longevity, percentage of attacked hosts, and progeny size per female, were recorded. The predator P. maculiventris was much less sensitive to azadirachtin, but slight reductions in survival of emerged adults and of reproductive parameters occurred. The insecticide had no significant effect on C. carnea larvae fed with treated Sitotroga cerealella (Oliver) eggs, probably because of its inability to penetrate inside the egg. 相似文献
6.
M. E. De Courcy Williams 《Biocontrol Science and Technology》2001,11(1):41-55
Difficulties in controlling outbreaks of Western flower thrips, Frankliniella occidentalis, have obstructed the widespread adoption of biological control in many ornamental crops. The efficacy of the predatory mite, Neoseiulus cucumeris, in controlling F. occidentalis on two cultivars of cyclamen was tested in glasshouse experiments. The establishment and development of F. occidentalis populations was compared in three treatment introductions of N. cucumeris (50, 200 and 350 mites m -2 per week) and an untreated control. F. occidentalis were sampled in the flowers over eight weeks and counted into different life stages. No differences were observed between the two cultivars. All treatments with the predator resulted in a decline in numbers of F. occidentalis compared to the untreated control. Although the proportion of first instar F. occidentalis was similar in all treatments, the level of control varied with the number of N. cucumeris introduced. Lower populations of F. occidentalis, combined with a more rapid decline in their numbers, were observed at the 200 and 350 mites m -2 rates. Numbers of F. occidentalis remained low in the 350 N. cucumeris m -2 rate and the proportion of second instar F. occidentalis in the samples was consistently lower than in the other treatments. Trap counts of adult F. occidentalis were strongly correlated with the numbers of both adult and total F. occidentalis in flower samples. High inoculative releases of N. cucumeris early in the flowering cycle followed by frequent low introductions of predators should provide a strong basis for preventative control of F. occidentalis and other thrips species on cyclamen. 相似文献
7.
The fungi, Hirsutella rhossiliensis and Hirsutella minnesotensis, are two endoparasites of second-stage juveniles (J2) of the soybean cyst nematode (SCN), Heterodera glycines. The objective of this study was to screen for effective fungal isolates to control the nematode in laboratory and greenhouse assays. A total of 93 isolates of H. rhossiliensis and 25 isolates of H. minnesotensis were evaluated for parasitism of SCN J2 on cornmeal agar. Percentage of SCN J2 parasitized by the fungi varied among the fungal isolates. Most H. rhossiliensis isolates parasitized a high percentage of J2. The isolates of H. rhossiliensis obtained from bacteria-feeding nematodes, however, generally did not parasitize J2 on agar. H. minnesotensis parasitized fewer J2 on agar than did H. rhossiliensis . Forty isolates of H. rhossiliensis and four isolates of H. minnesotensis that parasitized a high percentage of J2 on agar were evaluated for their biocontrol potential in soil treated with microwave heating. Most isolates selected from the agar assay also parasitized a high percentage of J2 in the soil but there was variation among isolates. Pathogenicity of 14 isolates of H. rhossiliensis and four isolates of H. minnesotensis to the SCN was also investigated in the greenhouse using untreated field soil. Most isolates of H. rhossiliensis reduced SCN population density and increased plant growth when compared with 1% corn-grits control (culture media). One isolate (OWVT-1) of H. rhossiliensis reduced the SCN egg density by 95% and J2 density by 98% when compared with the control. Isolates of H. minnesotensis, however, neither reduced SCN density nor increased plant growth in the greenhouse. 相似文献
8.
WANG Quan-Xi YU Jing ZHANG Xian-Chun ZHANG Da-Wei BAO Wen-Mei WANG Pei-Shan 《植物分类学报:英文版》2001,39(1):38-44
This paper is the first report of an investigation on the spore morphology of Chinese
ferns. Spore morphology of 20 species (10 species from China and 10 species from other countries)
in the genus Lygodium (Lygodiaceae) was investigated under scanning electron microscope (SEM)
and transmission electron microscope (TEM). The spores are tetrahedral-globose, trilete, rarely
monolete. The surface ornamentation of the spores can be divided into four main types: In type I ,
the surface of spores is tuberculate or spheroid-tuberculate. Most of the species of the genus have
this type of surface ornamentation of spores. In type II , the surface of spores is smooth. L. palmatum, L . subareolatum , L . yunnanense and L . volubile have this type of surface ornamentation
of spores. In type III, both the distal and equatorial areas of spores are coarsely verrucate, while
the proximal area is smooth. L. dimorphum, L. digitatum and L. kingii have this type of surface
ornamentation of spores. In type IV, the surface of spores is coarsely reticulate. L. scandens and
L. reticulatum have this type of surface ornamentation of spores. The surface contours of the reticulate type (type IV) are formed by the exospore, while that of the other types (types I, II, III)
are formed by the perispore. The surface ornamentation of spores seems to be stable within species
and thus is of important value in the taxonomy of the genus Lygodium. 相似文献
9.
Callicarpa x shirasawana is a natural hybrid between C. japonica and C. mollis, and has a morphology that is intermediate between those of the parent species. Characterization of natural Callicarpa populations in the Atsumi Peninsula of central Japan, which all three of the above species inhabit sympatrically, revealed hybrids with various morphologies. Molecular analysis revealed a high occurrence of introgression of the C. japonica genome into that of C. mollis. Moreover, all individuals examined with morphology similar to that of C. mollis had genetic traces of hybridization with C. japonica. Molecular analysis of individual C. mollis and C. japonica from five other areas of Japan showed that introgression of C. japonica into C. mollis occurs widely. Molecular data also strongly suggested that the previously recognized C. x shirasawana individuals with intermediate morphology are not F1 hybrids between C. japonica and C. mollis, but instead are progeny of C. x shirasawana backcrossed with C. japonica. Moreover, it was revealed that individuals with F1-type genotypes are indistinguishable morphologically from pure C. mollis. The results of the present study point to the need for re-evaluation of natural populations of C. mollis and C. x shirasawana. 相似文献
10.
Wang Wen-Tsai 《植物分类学报:英文版》1991,29(5):456-468
One variety of Eranthis, four species of Delphinium, one species of Anemone, and
two species and one variety of Clematis are described as new. The distribution of Anemone
reflexa Steph. in western part of Henan Province is reported for the first time. The
morphological variation of the inflorescence of Clematis armandii Franch.is elucidated, andaccording to it Clematis hefengensis G.F.Tao is reduced to a variety of C.armandii Franch. 相似文献
11.
The ascendancy concept aims at quantitatively describing the growth and development of an ecosystem as whole. Growth is an increase in the total system throughflow, while development is taken to be a rise in the average mutual information inherent in the network flow structure. As an ecosystem matures and goes through a series of successional stages, its ascendancy exhibits a propensity to increase. In any ecosystem the equilibrium condition may gradually turn into a chaotic situation for different reasons. In this paper a model is proposed of an aquatic ecosystem comprising of three groups, viz., phytoplankton, zooplankton and fish. Rate parameters are changed according to the change of the size of the organisms. The model is run in different conditions with gradual decrement of the body sizes of zooplankton. Allometric principle of the relationship of body size of zooplankton and two rate parameters (growth rate and half saturation constant) are incorporated in this model. According to allometric principle gradual decrement of body sizes of zooplankton consequently increases the grazing rate and decreases the half-saturation constant of this organisms. The system exhibits different states (equilibrium point--stable limit cycle--doubling and ultimately chaos) by gradual increase of zooplankton grazing rate and decrease of half-saturation constant. This paper tests the high level of ascendancy of the systems at the edge of oscillation before starting of the chaos. This high level of throughflow and mutual information, i.e. Ascendency supports the hypothesis that the system can coordinate the most complex behavior and shows maximum biocomplexity in this situation. 相似文献
12.
J. S. Weir R. Kiew F.L.S. 《Biological journal of the Linnean Society. Linnean Society of London》1986,27(2):113-132
Three species of epiphytic Dischidia have been investigated in terms of their relationship to ants on trees. Two species, D. parvifolia and D. astephana , are associated with ants and trees in montane areas. A clear association has been found between ants of the genus Crematogaster and the tree Leptospermum flavescens. This relationship is complex and probably both organisms benefit from the association. The ants live in tunnels in the wood of the major branches and the trunk, and the entire tree is occupied by one ant colony. Trees occupied by ants are maintained by the ants substantially clear of epiphytes other than the two species of Dischidia. The potential benefits to the tree and to the ants of this association are noted. The roots of D. astephana and D. parvifolia penetrate into the cavities of these ant nests and presumably gain nutrients from waste in the ant nests. Both Dischidia species are effectively scavenging upon the waste material from the ant-tree association. The leathery dome-shaped leaves of D. astephana are not vital to the development of the scavenging habit as D. parvifolia has lens-shaped leaves, but may offer some advantage to D. astephana by the uptake of nutrients from waste deposited by the ants under the dome-shaped leaves by interception of stem flow and by uptake of gaseous waste. Ants do not nest under these leaves. Seeds of these species of Dischidia are taken by ants into the central woody area of the ant nest where they germinate. Both Leptospermum and Dischidia can be visualized as showing adaptations to a nutient-deficient tropical montane environment. These adaptations are discussed as is the need for reassessment in this genus of the term 'ant-plant', and the need for wider recognition of the 1ant-tree' relationship between Crematogaster and Leptospermum. 相似文献
13.
Jean-François Martin Pêcheux 《Geobios》2002,35(4):469
Found in Chiapas (South-East of Mexico), Praealveolina michaudi nov. sp. and Chubbina jamaicensis (of Campanian-Maestrichtian age) are described, both evolved from Nummoloculina sp. while Raadshoovenia guatemalensis (upper Paleocene-lower Eocene) arises from Quinqueloculina. We precisely analyze and modelize the nepionic coiling during the evolutionary change from Miliolacea to Alveolinacea. During ontogenesis as well as during phylogenesis, quinqueloculine coiling progresses to streptospiral and then to planispiral chamber arrangement with the increase of volume of embryo and of chambers. Appearance of these large foraminifers are understood as a consequence of the rise of K-strategies in their mode of life, following the development of photosynthetic symbioses. 相似文献
14.
Research on the influence of sea level variations on the benthic faunas have been carried out in the Upper Ordovician of Sardinia. Study of the depositional facies and sequence analysis of the upper part (Lower Ashgill) of the Portixeddu Formation led to the identification of the sedimentary environments. Cystoids and crinoids are associated to bryozoans and brachiopods in most levels. The numerical analysis of associations and megaguilds shows that crinoids and cystoids have a higher frequency in the proximal and median facies of the upper offshore. The columnal association characterized by Conspectocrinus celticus and the coronoid Mespilocystites tregarvanicus has been discovered in the upper part of the formation. This material and complementary samples from Upper Ordovician of Sardinia and Kabylia (Algeria) bring additional data on the systematic and show the wide distribution of this fauna outside of the Ibero-armorican domain. The distribution of this echinoderm association supports a palaeogeographical position of the Ibero-armorican domain and Sardinia within the north gondwanan margin during the Lower Palaeozoic. 相似文献
15.
Mamoudou A Zoli A Hamadama H;Bourdanne Abah S Geerts S Clausen PH Zessin KH Kyule M van den Bossche P 《Medical and veterinary entomology》2008,22(1):32-36
Ten years after the large-scale tsetse control campaigns in the important cattle rearing areas of the Faro and Deo Division of the Adamaoua Plateau in Cameroon, the seasonal distribution and abundance of tsetse flies (Glossina spp.) were determined. During a period of 12 consecutive months (January-December 2005), the tsetse population was monitored along four trap transects consisting of a total of 32 traps and two flyround transects traversing the study area, which comprised the tsetse-infested valley, a buffer zone and the supposedly tsetse-free plateau. Throughout the study period, a total of 2195 Glossina morsitans submorsitans and 23 Glossina tachinoides were captured in the traps and 1007 G. m. submorsitans (78.8% male flies) were captured along the flyround transects. All G. tachinoides and almost all G. m. submorsitans were captured in the valley. Five G. m. submorsitans were captured in traps located in the buffer zone, whereas no flies were captured in traps located on the plateau. The index of apparent abundance (IAA) of G. m. submorsitans was substantially higher in the areas close to game reserves. In the remaining part of the valley, where wildlife is scarce and cattle are present during transhumance (dry season), the IAA of tsetse was substantially lower. In this part of the valley, the abundance of tsetse seemed to be associated with the presence of cattle, with the highest IAA during transhumance when cattle are present and the lowest apparent abundance during the rainy season when cattle have moved to the plateau. It is concluded that the distribution of tsetse in a large part of the valley undergoes substantial seasonal changes depending on the presence or absence of cattle. The repercussions of those findings for the control of tsetse in the valley and the probability of reinvasion of the plateau are discussed. 相似文献
16.
Pan Kai-Yu 《植物分类学报:英文版》1988,26(6):429-442
Ten new species, three new varieties and a new section of the family Gesneriaceae are described from China in the present paper. They are Tremacron urceolatum
K. Y. Pan from Muli of SW Sichuan, T. obliquifolium K. Y. Pan from Miyi and Yanyuan
of SW Sichuan, T. aurantiacum K. Y. Pan from Mabian and Pinshan of S Sichuan, lsometrum
Sect. Chorianthera W. T. Wang et K. Y. Pan (with I. eximium Chun as the section type),
Isometrum eximium Chun ex K. Y. Pan from Jiulong, Muli and Jinyang of SW Sichuan;
Ancylostemon mairei (Levl.) Craib var. emeiensis K. Y. Pan from Mt. Emei of Sichuan, A.
aureus (Franch.) Burtt var. angustifolius K. Y. Pan from Zhenkang of SW Yunnan, A. gamosepalus K. Y. Pan from Hanyuan, Yanyuan and Yuexi of SW Sichuan, A. rhombifolius K.
Y. Pan from Meigu of SW Sichuan, A. ronganensis K. Y. Pan from Rong an of Guangxi;
Corallodiscus flabellatus) (Craib) Burtt var. puberulus K.Y. Pan from Zhongdian and Deqin
of NW Yunnan, Nanchuan of S Sichuan and Zayü of Xizang (Tibet), Beccarinda minima
K. Y. Pan from Jinxiu and Xiangzhou of Guangxi, Boeica stolonifera K. Y. Pan from Fangcheng, Shiwandashan, Pingnan and Dongxing of S Guangxi, B. multinervia K. Y. Pan from
Yingjiang of W Yunnan, and Paraboea barbatipes K. Y. Pan from Napo of W Guangxi and
Xichou of SE Yunnan. 相似文献
17.
Aggregation and mating of thrips in flowers of Calystegia sepium 总被引:1,自引:0,他引:1
WILLIAM D. J. KIRK 《Ecological Entomology》1985,10(4):433-440
Abstract. 1. Aggregation and mating of Thrips major Uzel and Thrips fuscipennis Haliday (Thysanoptera: Thripidae) in the 1-day flowers of Calystegia sepium (L.) R.Br. are described.
2. The number of thrips per flower increased rapidly after flower-opening at dawn and decreased during the evening and following morning.
3. Males patrolled the corolla, attempting to copulate with any females that landed. Their movement was affected by the density of thrips on the corolla. Most females were among the stamens and style, apparently feeding on pollen.
4. These thrips were also abundant in flowers of Filipendula ulmaria (L.) Maxim. They fed on pollen, and grains adhered to them. They may be significant pollinators because of their high frequency of flights.
5. The aggregations appear to be a simple consequence of general flower-finding responses to colour and scent that are particularly elicited by flowers of C.sepium and F.ulmaria. The ecological significance of male aggregations is discussed. 相似文献
2. The number of thrips per flower increased rapidly after flower-opening at dawn and decreased during the evening and following morning.
3. Males patrolled the corolla, attempting to copulate with any females that landed. Their movement was affected by the density of thrips on the corolla. Most females were among the stamens and style, apparently feeding on pollen.
4. These thrips were also abundant in flowers of Filipendula ulmaria (L.) Maxim. They fed on pollen, and grains adhered to them. They may be significant pollinators because of their high frequency of flights.
5. The aggregations appear to be a simple consequence of general flower-finding responses to colour and scent that are particularly elicited by flowers of C.sepium and F.ulmaria. The ecological significance of male aggregations is discussed. 相似文献
18.
Naoki Fujitani Setsuko Sakaki Yuji Yamaguchi Hiroyuki Takenaka 《Journal of applied phycology》2001,13(6):489-492
The inhibitory effects of seven microalgae, Nostoc flagelliforme, Spirulina platensis, Porphyridium purpureum, Rhodosorus marinus,Chlorella pyrenoidosa, Dunaliella salina and Pleurochrysiscarterae on the activation of hyaluronidase were evaluated. Theinhibitory effect of the ethanol-insoluble fraction of each water extract frommicroalgae was stronger than that of the ethanol-soluble fraction. The50% inhibitory concentration (IC50) of the ethanol-insolublefraction of S. platensis, P. purpureum, R. marinus, C.pyrenoidosa, D. salina and P. carterae was 0.15, 0.18, 0.26,0.94, 0.15 and 0.41 mg mL-1, respectively. The IC50 ofN .flagelliforme was not calculated, because there was no detectableinhibitory effect of this alga. The IC50 of disodium cromoglycate(DSCG) used as the anti-allergic medicine was 0.14 mg mL-1. The IC50 of S. platensis, P. purpureum and D. salinawere almost the same as that of DSCG. This suggests that theethanol-insoluble fraction of S. platensis, P. purpureum and D. salina might be an anti-allergic substance. The ethanol-insoluble fractionof S. platensis and D. salina was ultrafiltered through a membranehaving a molecular exclusion limit of 20 kDa. The IC50 of theresidue was stronger than that of the filtrate. These results suggest that theanti-allergic substance(s) of these microalgae may be polysaccharides. 相似文献
19.
ALAN R. HEMSLEY 《Botanical journal of the Linnean Society. Linnean Society of London》2001,137(4):375-384
The fossil record of bryophytes is generally poor and infertile plants attributable to liverworts and mosses could also be thalloid vascular plant gametophytes or herbaceous lycophytes respectively. The paucity of the bryophytic record could be the result of relatively rapid degradation of bryophytic material in comparison to that of vascular plants, the absence of lignified cells in bryophytes sustaining this belief. However, certain organs of bryophytes are as robust as those of vascular plants (e.g. spores) and the hydroxybenzofuran polymers produced by some mosses could be of similar preservational resistance to lignins. A simplistic experiment to test the relative resistance to decay of bryophytic material has been undertaken. Its findings suggest that bryophytic plant material has a similar preservational potential to that of a selected vascular plant, particularly in organic rich sediments. This result may be construed to imply that bryophytes were indeed less abundant in the preservational environments of the Coal Measures than might be expected on the basis of current palaeoenvironmental reconstructions. 相似文献
20.
Phylogenetic definitions and taxonomic philosophy 总被引:4,自引:0,他引:4
Kevin de Queiroz 《Biology & philosophy》1992,7(3):295-313
An examination of the post-Darwinian history of biological taxonomy reveals an implicit assumption that the definitions of taxon names consist of lists of organismal traits. That assumption represents a failure to grant the concept of evolution a central role in taxonomy, and it causes conflicts between traditional methods of defining taxon names and evolutionary concepts of taxa. Phylogenetic definitions of taxon names (de Queiroz and Gauthier 1990) grant the concept of common ancestry a central role in the definitions of taxon names and thus constitute an important step in the development of phylogenetic taxonomy. By treating phylogenetic relationships rather than organismal traits as necessary and sufficient properties, phylogenetic definitions remove conflicts between the definitions of taxon names and evolutionary concepts of taxa. The general method of definition represented by phylogenetic definitions of clade names can be applied to the names of other kinds of composite wholes, including populations and biological species. That the names of individuals (composite wholes) can be defined in terms of necessary and sufficient properties provides the foundation for a synthesis of seemingly incompatible positions held by contemporary individualists and essentialists concerning the nature of taxa and the definitions of taxon names. 相似文献