Many ' species ' in this genus hybridise so readily that species boundaries themselves are vague, with regular name changes and no clear answers.

The taxonomy of the swifts is in general complicated, with genus and species boundaries widely disputed, especially amongst the swiftlets.

The exact delimitation of boundaries of the family are uncertain, for example the genus Mohoua, which is endemic to New Zealand has been placed with the family based on a number of morphological features and DNA-DNA hybridization studies, but the placement is still controversial.

Species boundaries are not clear in the genus, and in spite of having been intensively studied, the number of species recognized by different authorities varies from 6 to 10.

The starling genera have been found to be polyphyletic lead to the redefinition of genus boundaries.

Even the generic boundaries of the genus are controversial.

There are also many older Japanese hybrids and forms, extending the boundaries of the genus in cultivation.

Various members of the genus ( especially Spartina alterniflora and its derivatives, Spartina anglica and Spartina × townsendii ) have spread outside of their native boundaries and become invasive.

Delimitation of species boundaries within the genus Chlorophytum is reported to be difficult, possibly because of several evolutionary radiations into forest environments that led to morphological aspects that are too similar to reliably distinguish separate species.

Thalictrum is a taxonomically difficult genus with poorly understood species boundaries ; it is in need of further taxonomic and field research for clarification.

Authors differ on precise boundaries of the genus, which has been included in Cylindropuntia.

The boundaries of the Asparagales and of its families have undergone a series of changes in recent years ; future research may lead to further changes and ultimately greater stability.

These boundaries have since become blurred, and it should be noted even in times long gone, many ballroom dances were really elevated folk dances.

A decisive battle can have political as well as military impact, changing the balance of power or boundaries between countries.

In the final block of ice, each of the small crystals ( called " crystallites " or " grains ") is a true crystal with a periodic arrangement of atoms, but the whole polycrystal does not have a periodic arrangement of atoms, because the periodic pattern is broken at the grain boundaries.

Comic book historians continue to debate the exact boundaries of these eras, but they have come to an agreement, the terms for which originated in the fan press.

The Maritimes are the only provinces in Canada which entered Confederation in the 19th century and have kept their original colonial boundaries.

A 2009 psychiatric review noted that attempts to demonstrate natural boundaries between related DSM syndromes, or between a common DSM syndrome and normality, have failed.

Taken as a physical description of space, postulate 2 ( extending a line ) asserts that space does not have holes or boundaries ( in other words, space is homogeneous and unbounded ); postulate 4 ( equality of right angles ) says that space is isotropic and figures may be moved to any location while maintaining congruence ; and postulate 5 ( the parallel postulate ) that space is flat ( has no intrinsic curvature ).

The school claims to not have disciplinary boundaries, so students do not major, but rather concentrate in a field or concept.

Local congregations ( branches, wards, and stakes ) have de jure boundaries by which members are allocated, and membership records are centralized.

A given stage of rock and the corresponding age of time will by convention have the same name, and the same boundaries.

First, if planar regions separated by the graph are not triangulated, i. e. do not have exactly three edges in their boundaries, we can add edges without introducing new vertices in order to make every region triangular, including the unbounded outer region.

Outside the limited boundaries of the old city, a variety of arrangements have governed the wider area since 1855, culminating with the creation of the Greater London administrative area in 1965.

His works are frequently performed in opera houses throughout the world and, transcending the boundaries of the genre, some of his themes have long since taken root in popular culture – such as " La donna è mobile " from Rigoletto, " Va, pensiero " ( The Chorus of the Hebrew Slaves ) from Nabucco, " Libiamo ne ' lieti calici " ( The Drinking Song ) from La traviata and the " Grand March " from Aida.

They have obvious self interest in determining boundaries to their and their party's interest.

The boundaries of Greater Poland have varied somewhat throughout history.

; Mistrust authority — promote decentralization: The best way to promote the free exchange of information is to have an open system that presents no boundaries between a hacker and a piece of information or an item of equipment that he needs in his quest for knowledge, improvement, and time on-line.

The first 32 divisions listed below are the " traditional " counties, 20 of which still have administrative functions as local government divisions in the Republic of Ireland ( in some cases with slightly redrawn boundaries ).

Article 4 of the Constitution of the Republic of China originally stated that " he territory of the Republic of China within its existing national boundaries shall not be altered except by a resolution of the National Assembly ", although recent constitutional changes have moved this power to that of a national referendum.

There have long been debates in the jazz community over the definition and the boundaries of “ jazz ”.

Jordan's boundaries with Syria, Iraq, and Saudi Arabia do not have the special significance that the border with Israel does ; these borders have not always hampered tribal nomads in their movements, yet for a few groups borders did separate them from traditional grazing areas and delimited by a series of agreements between the United Kingdom and the government of what eventually became Saudi Arabia ) was first formally defined in the Hadda Agreement of 1925.

But no matter how powerful each body may appear to be, the extent to which any of the judgments may be enforced, or proposed treaties and conventions may become or remain effective within the territorial boundaries of each nation is a political matter under the sovereign control of the relevant representative government ( s ) which, in a democratic context, will have electorates to satisfy.

Following the emergence of independent post-Soviet states, the rail lines which were built without regard for administrative boundaries have been cut by borders, and traffic is therefore severely curtailed.

Workers have a right to strike when they feel their boundaries are being crossed and the best way for the employer to fix the employees unhappiness is to come to a mutual agreement.

The largest of these contingents was that of the Goths, who in 382, had been allowed to settle within the imperial boundaries, keeping a large degree of autonomy.

Delimitation of international boundaries in the vicinity of Lake Chad, the lack of which led to border incidents in the past, has been completed and awaits ratification by Cameroon, Chad, Niger, and Nigeria.

" Documentary " has been described as a " filmmaking practice, a cinematic tradition, and mode of audience reception " that is continually evolving and is without clear boundaries.

In antiquity, the Greek historian Herodotus mentioned that the world had been divided by unknown persons into three parts, Europe, Asia, and Libya ( Africa ), with the Nile and the River Phasis forming their boundaries — though he also states that some considered the River Don, rather than the Phasis, as the boundary between Europe and Asia.

Although the London County Council had been created as a London-wide authority covering the County of London in 1889, the county did not cover all the built-up area of London, particularly West Ham and East Ham ; and many of the LCC housing projects, including the vast Becontree Estate, were outside its boundaries.

The dry-stone walls which separate fields and mark boundaries give an idea of the extent to which the landscape has been shaped by farming.

The territory's boundaries had not been defined in the 1762 Treaty of Fontainebleau that ceded it from France to Spain, nor the 1800 Third Treaty of San Ildefonso ceding it back to France, nor the 1803 Louisiana Purchase agreement ceding it to the United States.

Lithuania's boundaries have changed several times since 1918, but they have been stable since 1945.

Lansing currently lies mostly within the boundaries of Michigan's 8th congressional district, which has been represented by Republican congressman Mike Rogers since 2001.

Family boundaries and circumscriptions of the " core Malvales " families Malvaceae, Bombacaceae, Tiliaceae, and Sterculiaceae have long been problematic.

On Chomsky specifically, he writes that " imaginary problems were created by the whole series of dichotomies that Chomsky introduced, or took over unproblematized: not only syntax / semantics but also grammar / lexis, language / thought, competence / performance ... Once these dichotomies had been set up, the problem arose of locating and maintaining the boundaries between them linguistics "

The boundaries between these specialties have been blurring recently as they are all influenced by basic research in neuroscience.

There have been several decades of unresolved discussions regarding the delimitation of international boundaries in the vicinity of Lake Chad between Niger, Nigeria, Chad, and Cameroon.

Delimitation of international boundaries in the vicinity of Lake Chad, the lack of which led to border incidents in the past, has been completed and awaits ratification by Cameroon, Chad, Niger, and Nigeria ; dispute with Cameroon over land and maritime boundaries around the Bakasi Peninsula is currently before the ICJ ; maritime boundary dispute with Equatorial Guinea because of disputed jurisdiction over oil-rich areas in the Gulf of Guinea.

In recent years the boundaries between these sub-disciplines have increasingly been dissolving as moral theorists become more interested in applied problems and applied ethics is becoming more profoundly philosophically informed.

The locations of Sattagydia and Hindush and the extent of their boundaries have not been identified either though it is certain that these two tributaries existed along the river Indus as the name Hindush is analogous with the Indus and was derived by the Persians from the Sanskrit word Sindhu.

The country's two international boundaries, with Colombia and Costa Rica, have been clearly demarcated, and in the late 1980s there were no outstanding disputes.

It has been established that modern policing has transgressed national boundaries from time to time almost from its inception.

Specific sites linked to Robin Hood include the Major Oak tree, claimed to have been used by him as a hideout, Robin Hood's Well, located near Newstead Abbey ( within the boundaries of Sherwood Forest ), and the Church of St. Mary in the village of Edwinstowe, where Robin and Maid Marian are historically thought to have wed. To reinforce this belief, the University of Nottingham in 2010 has begun the Nottingham Caves Survey with the goal " to increase the tourist potential of these sites ".

Several models have been proposed for understanding the activities required to manage material movements across organizational and functional boundaries.

During the twentieth century the relationship between science and spirituality has been influenced both by Freudian psychology, which has accentuated the boundaries between the two areas by accentuating individualism and secularism, and by developments in particle physics, which reopened the debate about complementarity between scientific and religious discourse and rekindled for many an interest in holistic conceptions of reality.

India's government held the view that the Himalayas were the ancient boundaries of the Indian subcontinent, and thus should be the modern boundaries of India, while it is the position of the Chinese government that the disputed area in the Himalayas have been geographically and culturally part of Tibet since ancient times.