Within each cla.s.s the flower-characters as the essential feature of Angiosperms supply the clue to phylogeny, but the uncertainty regarding the construction of the primitive angiospermous flower gives a fundamental point of divergence in attempts to construct progressive sequences of the families. Simplicity of flower-structure has appeared to some to be always primitive, whilst by others it has been taken to be always derived. There is, however, abundant evidence that it may have the one or the other character in different cases. Apart from this, botanists are generally agreed that the concrescence of parts of the flower-whorls--in the gynaeceum as the seed-covering, and in the corolla as the seat of attraction, more than in the androecium and the calyx--is an indication of advance, as is also the concrescence that gives the condition of epigyny. Dorsiventrality is also clearly derived from radial construction, and anatropy of the ovule has followed atropy. We should expect the alb.u.minous state of the seed to be an antecedent one to the exalb.u.minous condition, and the recent discoveries in fertilization tend to confirm this view. Amongst Dicotyledons the gamopetalous forms are admitted to be the highest development and a dominant one of our epoch. Advance has been along two lines, markedly in relation to insect-pollination, one of which has culminated in the hypogynous epipetalous bicarpellate forms with dorsiventral often large and loosely arranged flowers such as occur in Scrophulariaceae, and the other in the epigynous bicarpellate small-flowered families of which the Compositae represent the most elaborate type. In the polypetalous forms progression from hypogyny to epigyny is generally recognized, and where dorsiventrality with insect-pollination has been established, a dominant group has been developed as in the Leguminosae. The starting-point of the cla.s.s, however, and the position within it of apetalous families with frequently unis.e.xual flowers, have provoked much discussion. In Monocotyledons a similar advance from hypogyny to epigyny is observed, and from the dorsiventral to the radial type of flower. In this connexion it is noteworthy that so many of the higher forms are adapted as bulbous geophytes, or as aerophytes to special xerophilous conditions. The Gramineae offer a prominent example of a dominant self-pollinated or wind-pollinated family, and this may find explanation in a multiplicity of factors.

Though best known for his artificial (or s.e.xual) system, Linnaeus was impressed with the importance of elaborating a natural system of arrangement in which plants should be arranged according to their true affinities. In his _Philosophia Botanica_ (1751) Linnaeus grouped the genera then known into sixty-seven orders (_fragmenta_), all except five of which are Angiosperms. He gave names to these but did not characterize them or attempt to arrange them in larger groups.

Some represent natural groups and had in several cases been already recognized by Ray and others, but the majority are, in the light of modern knowledge, very mixed. Well-defined polypetalous and gamopetalous genera sometimes occur in the same order, and even Monocotyledons and Dicotyledons are cla.s.sed together where they have some striking physiological character in common.

Work on the lines suggested by the Linnaean _fragmenta_ was continued in France by Bernard de Jussieu and his nephew, Antoine Laurent, and the arrangement suggested by the latter in his _Genera Plantarum secundum Ordines Naturales disposita_ (1789) is the first which can claim to be a natural system. The orders are carefully characterized, and those of Angiosperms are grouped in fourteen cla.s.ses under the two main divisions Monocotyledons and Dicotyledons. The former comprise three cla.s.ses, which are distinguished by the relative position of the stamens and ovary; the eleven cla.s.ses of the latter are based on the same set of characters and fall into the larger subdivisions Apetalae, Monopetalae and Polypetalae, characterized respectively by absence, union or freedom of the petals, and a subdivision, _Diclines Irregulares_, a very unnatural group, including one cla.s.s only. A.P.

de Candolle introduced several improvements into the system. In his arrangement the last subdivision disappears, and the Dicotyledons fall into two groups, a larger containing those in which both calyx and corolla are present in the flower, and a smaller, Monochlamydeae, representing the Apetalae and _Diclines Irregulares_ of Jussieu.

The dichlamydeous group is subdivided into three, Thalamiflorae, Calyciflorae and Corolliflorae, depending on the position and union of the petals. This, which we may distinguish as the French system, finds its most perfect expression in the cla.s.sic _Genera Plantarum_ (1862-1883) of Bentham and Hooker, a work containing a description, based on careful examination of specimens, of all known genera of flowering plants. The subdivision is as follows:--

DICOTYLEDONS.

Polypetalae: Thalamiflorae.

Disciflorae.

Calyciflorae.

Gamopetalae: Inferae.

Heteromerae.

Bicarpellatae.

Monochlamydeae in eight series.

Monocotyledons in seven series.

Of the Polypetalae, series 1, Thalamiflorae, is characterized by hypogynous petals and stamens, and contains 34 orders distributed in 6 larger groups or cohorts. Series 2, Disciflorae, takes its name from a development of the floral axis which forms a ring or cushion at the base of the ovary or is broken up into glands; the ovary is superior.

It contains 23 orders in 4 cohorts. Series 3, Calyciflorae, has petals and stamens perigynous, or sometimes superior. It contains 27 orders in 5 cohorts.

Of the Gamopetalae, series 1, Inferae, has an interior ovary and stamens usually as many as the corolla-lobes. It contains 9 orders in 3 cohorts. Series 2, Heteromerae, has generally a superior ovary, stamens as many as the corolla-lobes or more, and more than two carpels. It contains 12 orders in 3 cohorts. Series 3, Bicarpellatae, has generally a superior ovary and usually two carpels. It contains 24 orders in 4 cohorts.

The eight series of Monochlamydeae, containing 36 orders, form groups characterized mainly by differences in the ovary and ovules, and are now recognized as of unequal value.

The seven series of Monocotyledons represent a sequence beginning with the most complicated epigynous orders, such as Orchideae and Scitamineae, and pa.s.sing through the petaloid hypogynous orders (series Coronarieae) of which Liliaceae is the representative to Juncaceae and the palms (series Calycinae) where the perianth loses its petaloid character and thence to the Aroids, screw-pines and others where it is more or less aborted (series Nudiflorae). Series 6, Apocarpeae, is characterized by 5 carpels, and in the last series Glumaceae, great simplification in the flower is a.s.sociated with a gra.s.s-like habit.

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The sequence of orders in the polypetalous subdivision of Dicotyledons undoubtedly represents a progression from simpler to more elaborate forms, but a great drawback to the value of the system is the inclusion among the Monochlamydeae of a number of orders which are closely allied with orders of Polypetalae though differing in absence of a corolla. The German systematist, A.W. Eichler, attempted to remove this disadvantage which since the time of Jussieu had characterized the French system, and in 1883 grouped the Dicotyledons in two subcla.s.ses. The earlier Choripetalae embraces the Polypetalae and Monochlamydae of the French systems. It includes 21 series, and is an attempt to arrange as far as possible in a linear series those orders which are characterized by absence or freedom of petals. The second subcla.s.s, Gamopetalae, includes 9 series and culminates in those which show the most elaborate type of flower, the series Aggregatae, the chief representative of which is the great and wide-spread order Compositae. A modification of Eichler's system, embracing the most recent views of the affinities of the orders of Angiosperms, has been put forward by Dr. Adolf Engler of Berlin, who adopts the suggestive names Archichlamydeae and Metachlamydeae for the two subdivisions of Dicotyledons. Dr. Engler is the princ.i.p.al editor of a large series of volumes which, under the t.i.tle _Die naturlichen Pflanzenfamilien_, is a systematic account of all the known genera of plants and represents the work of many botanists. More recently in _Das Pflanzenreich_ the same author organized a series of complete monographs of the families of seed-plants.

As an attempt at a phylogenetic arrangement, Engler's system is now preferred by many botanists. More recently a startling novelty in the way of system has been produced by van Tieghem, as follows:

Monocotyledons.

Liorhizal Dicotyledons.

Dicotyledons.

INSEMINEAE.

SEMINEAE.

_Unitegmineae.

Bitegmineae_.

The most remarkable feature here is the cla.s.s of Liorhizal Dicotyledons, which includes only the families of Nymphaeaceae and Gramineae. It is based upon the fact that the histological differentiation of the epidermis of their root is that generally characteristic of Monocotyledons, whilst they have two cotyledons--the old view of the epiblast as a second cotyledon in Gramineae being adopted. But the presence of a second cotyledon in gra.s.ses is extremely doubtful, and though there may be ground for reconsidering the position of Nymphaeaceae, their a.s.sociation with the gra.s.ses as a distinct cla.s.s is not warranted by a comparative examination of the members of the two orders. Ovular characters determine the grouping in the Dicotyledons, van Tieghem supporting the view that the integument, the outer if there be two, is the lamina of a leaf of which the funicle is the petiole, whilst the nucellus is an outgrowth of this leaf, and the inner integument, if present, an indusium. The Insemineae include forms in which the nucellus is not developed, and therefore there can be no seed. The plants included are, however, mainly well-established parasites, and the absence of nucellus is only one of those characters of reduction to which parasites are liable.

Even if we admit van Tieghem's interpretation of the integuments to be correct, the diagnostic mark of his unitegminous and bitegminous groups is simply that of the absence or presence of an indusium, not a character of great value elsewhere, and, as we know, the number of the ovular coats is inconstant within the same family. At the same time the groups based upon the integuments are of much the same extent as the Polypetalae and Gamopetalae of other systems. We do not yet know the significance of this correlation, which, however, is not an invariable one, between number of integuments and union of petals.

Within the last few years Prof. John Coulter and Dr. C.J. Chamberlain of Chicago University have given a valuable general account of the morphology of Angiosperms as far as concerns the flower, and the series of events which ends in the formation of the seed (_Morphology of Angiosperms_, Chicago, 1903).

AUTHORITIES.--The reader will find in the following works details of the subject and references to the literature: Bentham and Hooker, _Genera Plantarum_ (London, 1862-1883); Eichler, _Bluthendiagramme_ (Leipzig, 1875-1878); Engler and Prantl, _Die naturlichen Pflanzenfamilien_ (Leipzig, 1887-1899); Engler, _Syllabus der Pflanzenfamilien_, 3rd ed. (Berlin, 1903); Knuth, _Handbuch der Blutenbiologie_ (Leipzig, 1898, 1899); Sachs, _History of Botany_, English ed. (Oxford, 1890); Solereder, _Systematische Anatomie der Dicotyledonen_ (Stuttgart, 1899); van Tieghem, _Elements de botanique_; Coulter and Chamberlain, _Morphology of Angiosperms_ (New York, 1903).

(I.B.B.; A.B.R.)

ANGKOR, an a.s.semblage of ruins in Cambodia, the relic of the ancient Khmer civilization. They are situated in forests to the north of the Great Lake (Tonle-Sap), the most conspicuous of the remains being the town of Angkor-Thom and the temple of Angkor-Vat, both of which lie on the right bank of the river Siem-Reap, a tributary of Tonle-Sap.

Other remains of the same form and character lie scattered about the vicinity on both banks of the river, which is crossed by an ancient stone bridge.

Angkor-Thom lies about a quarter of a mile from the river. According to Aymonier it was begun about A.D. 860, in the reign of the Khmer sovereign Jayavarman III., and finished towards A.D. 900. It consists of a rectangular enclosure, nearly 2 m. in each direction, surrounded by a wall from 20 to 30 ft. in height. Within the enclosure, which is entered by five monumental gates, are the remains of palaces and temples, overgrown by the forest. The chief of these are:--

(1) The vestiges of the royal palace, which stood within an enclosure containing also the pyramidal religious structure known as the Phimeanakas. To the east of this enclosure there extends a terrace decorated with magnificent reliefs.

(2) The temple of Bayon, a square enclosure formed by galleries with colonnades, within which is another and more elaborate system of galleries, rectangular in arrangement and enclosing a cruciform structure, at the centre of which rises a huge tower with a circular base. Fifty towers, decorated with quadruple faces of Brahma, are built at intervals upon the galleries, the whole temple ranking as perhaps the most remarkable of the Khmer remains.

Angkor-Vat, the best preserved example of Khmer architecture, lies less than a mile to the south of the royal city, within a rectangular park surrounded by a moat, the outer perimeter of which measures 6060 yds. On the west side of the park a paved causeway, leading over the moat and under a magnificent portico, extends for a distance of a quarter of a mile to the chief entrance of the main building. The temple was originally devoted to the worship of Brahma, but afterwards to that of Buddha; its construction is a.s.signed by Aymonier to the first half of the 12th century A.D. It consists of three stages, connected by numerous exterior staircases and decreasing in dimensions as they rise, culminating in the sanctuary, a great central tower pyramidal in form. Towers also surmount the angles of the terraces of the two upper stages. Three galleries with vaulting supported on columns lead from the three western portals to the second stage.

They are connected by a transverse gallery, thus forming four square basins. Khmer decoration, profuse but harmonious, consists chiefly in the representation of G.o.ds, men and animals, which are displayed on every flat surface. Combats and legendary episodes are often depicted; floral decoration is reserved chiefly for borders, mouldings and capitals. Sandstone of various colours was the chief material employed by the Khmers; limonite was also used. The stone was cut into huge blocks which are fitted together with great accuracy without the use of cement.

See E. Aymonier, _Le Cambodge_ (3 vols., 1900-1904); Doudart de Lagree, _Voyage d'exploration en Indo-Chine_ (1872-1873); A.H. Mouhot, _Travels in Indo-China, Cambodia and Laos_ (2 vols., 1864); Fournereau and Porcher, _Les Ruines d'Angkor_ (1890); L. Delaporte, _Voyage au Cambodge: l'architecture Khmer_ (1880); J. Moura, _Le Royaume de Cambodge_ (2 vols., 1883).

ANGLE (from the Lat. _angulus_, a corner, a diminutive, of which the primitive form, _angus_, does not occur in Latin; cognate are the Lat.

_angere_, to compress into a bend or to strangle, and the Gr. [Greek: ankos], a bend; both connected with the Aryan root _ank_-, to bend: see ANGLING), in geometry, the inclination of one line or plane to another. Euclid (_Elements_, book I) defines a plane angle as the inclination to each other, in a plane, of two lines which meet each other, and do not lie straight with respect to each other (see GEOMETRY, EUCLIDEAN). According to Proclus an angle must be either a quality or a quant.i.ty, or a relationship. The first concept was utilized by Eudemus, who regarded an angle as a deviation from a straight line; the second by Carpus of Antioch, who regarded it as the interval or s.p.a.ce between the intersecting lines; Euclid adopted the third concept, although his definitions of right, acute, and obtuse angles are certainly quant.i.tative. A discussion of these concepts and the various definitions of angles in Euclidean geometry is to be found in W.B. Frankland, _The First Book of Euclid's Elements_ (1905).

Following Euclid, a right angle is formed by a straight line standing upon another straight line so as to make the adjacent angles equal; any angle less than a right angle is termed an acute angle, and any angle greater than a right angle an obtuse angle. The difference between an acute angle and a right angle is termed the complement of the angle, and between an angle and two right angles the supplement of the angle. The generalized view of angles and their measurement is treated in the article TRIGONOMETRY. A solid angle is definable as the s.p.a.ce contained by three or more planes intersecting in a common point; it is familiarly represented by a corner. The angle between two planes is termed dihedral, between three trihedral, between any number more than three polyhedral. A spherical angle is a particular dihedral angle; it is the angle between two intersecting arcs on a sphere, and is measured by the angle between the planes containing the arcs and the centre of the sphere.

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The angle between a line and a curve (mixed angle) or between two curves (curvilinear angle) is measured by the angle between the line and the tangent at the point of intersection, or between the tangents to both curves at their common point. Various names (now rarely, if ever, used) have been given to particular cases:--amphicyrtic (Gr.

[Greek: amphi], on both sides, [Greek: kyrtos], convex) or cissoidal (Gr. [Greek: kissos], ivy), biconvex; xystroidal or sistroidal (Gr.

[Greek: xystris], a tool for sc.r.a.ping), concavo-convex; amphicoelic (Gr. [Greek: koilae], a hollow) or _angulus lunularis_, biconcave.

[Ill.u.s.tration: The Angler (_Lophius piscatorius_).]

ANGLER, also sometimes called fishing-frog, frog-fish, sea-devil (_Lophius piscatorius_), a fish well known off the coasts of Great Britain and Europe generally, the grotesque shape of its body and its singular habits having attracted the attention of naturalists of all ages. To the North Sea fishermen this fish is known as the "monk," a name which more properly belongs to _Rhina squatina_, a fish allied to the skates. Its head is of enormous size, broad, flat and depressed, the remainder of the body appearing merely like an appendage. The wide mouth extends all round the anterior circ.u.mference of the head; and both jaws are armed with bands of long pointed teeth, which are inclined inwards, and can be depressed so as to offer no impediment to an object gliding towards the stomach, but to prevent its escape from the mouth. The pectoral and ventral fins are so articulated as to perform the functions of feet, the fish being enabled to move, or rather to walk, on the bottom of the sea, where it generally hides itself in the sand or amongst sea-weed. All round its head and also along the body the skin bears fringed appendages resembling short fronds of sea-weed, a structure which, combined with the extraordinary faculty of a.s.similating the colour of the body to its surroundings, a.s.sists this fish greatly in concealing itself in places which it selects on account of the abundance of prey. To render the organization of this creature perfect in relation to its wants, it is provided with three long filaments inserted along the middle of the head, which are, in fact, the detached and modified three first spines of the anterior dorsal fin. The filament most important in the economy of the angler is the first, which is the longest, terminates in a lappet, and is movable in every direction. The angler is believed to attract other fishes by means of its lure, and then to seize them with its enormous jaws. It is probable enough that smaller fishes are attracted in this way, but experiments have shown that the action of the jaws is automatic and depends on contact of the prey with the tentacle. Its stomach is distensible in an extraordinary degree, and not rarely fishes have been taken out quite as large and heavy as their destroyer. It grows to a length of more than 5 ft.; specimens of 3 ft. are common. The sp.a.w.n of the angler is very remarkable. It consists of a thin sheet of transparent gelatinous material 2 or 3 ft. broad and 25 to 30 ft. in length. The eggs in this sheet are in a single layer, each in its own little cavity. The sp.a.w.n is free in the sea. The larvae are free-swimming and have the pelvic fins elongated into filaments. The British species is found all round the coasts of Europe and western North America, but becomes scarce beyond 60 N.

lat.; it occurs also on the coasts of the Cape of Good Hope. A second species (_Lophius budega.s.sa_) inhabits the Mediterranean, and a third (_L. setigerus_) the coasts of China and j.a.pan.

ANGLESEY, ARTHUR ANNESLEY, 1st EARL OF (1614-1686), British statesman, son of the 1st Viscount Valentia (cr. 1621) and Baron Mountnorris (cr.

1628), and of Dorothy, daughter of Sir John Philipps of Picton Castle, Pembrokeshire, was born at Dublin on the 10th of July 1614, was educated at Magdalen College, Oxford, and was admitted to Lincoln's Inn in 1634. Having made the grand tour he returned to Ireland; and being employed by the parliament in a mission to the duke of Ormonde, now reduced to the last extremities, he succeeded in concluding a treaty with him on the 19th of June 1647, thus securing the country from complete subjection to the rebels. In April 1647 he was returned for Radnorshire to the House of Commons. He supported the parliamentary as against the republican or army party, and appears to have been one of the members excluded in 1648. He sat in Richard Cromwell's parliament for Dublin city, and endeavoured to take his seat in the restored Rump Parliament of 1659. He was made president of the council in February 1660, and in the Convention Parliament sat for Carmarthen borough. The anarchy of the last months of the commonwealth converted him to royalism, and he showed great activity in bringing about the Restoration. He used his influence in moderating measures of revenge and violence, and while sitting in judgment on the regicides was on the side of leniency. In November 1660 by his father's death he had become Viscount Valentia and Baron Mountnorris in the Irish peerage, and on the 20th April 1661 he was created Baron Annesley of Newport Pagnell in Buckinghamshire and earl of Anglesey in the peerage of Great Britain. He supported the king's administration in parliament, but opposed strongly the unjust measure which, on the abolition of the court of wards, placed the extra burden of taxation thus rendered necessary on the excise. His services in the administration of Ireland were especially valuable. He filled the office of vice-treasurer from 1660 till 1667, served on the committee for carrying out the declaration for the settlement of Ireland and on the committee for Irish affairs, while later, in 1671 and 1672, he was a leading member of various commissions appointed to investigate the working of the Acts of Settlement. In February 1661 he had obtained a captaincy of horse, and in 1667 he exchanged his vice-treasuryship of Ireland for the treasuryship of the navy. His public career was marked by great independence and fidelity to principle. On the 24th of July 1663 he alone signed a protest against the bill "for the encouragement of trade," on the plea that owing to the free export of coin and bullion allowed by the act, and to the importation of foreign commodities being greater than the export of home goods, "it must necessarily follow ... that our silver will also be carried away into foreign parts and all trade fail for want of money."[1] He especially disapproved of another clause in the same bill forbidding the importation of Irish cattle into England, a mischievous measure promoted by the duke of Buckingham, and he opposed again the bill brought in with that object in January 1667. This same year his naval accounts were subjected to an examination in consequence of his indignant refusal to take part in the attack upon Ormonde;[2] and he was suspended from his office in 1668, no charge, however, against him being substantiated. He took a prominent part in the dispute in 1671 between the two Houses concerning the right of the Lords to amend money bills, and wrote a learned pamphlet on the question ent.i.tled _The Privileges of the House of Lords and Commons_ (1702), in which the right of the Lords was a.s.serted. In April 1673 he was appointed lord privy seal, and was disappointed at not obtaining the great seal the same year on the removal of Shaftesbury. In 1679 he was included in Sir W. Temple's new-modelled council.

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In the bitter religious controversies of the time Anglesey showed great moderation and toleration. In 1674 he is mentioned as endeavouring to prevent the justices putting into force the laws against the Roman Catholics and Nonconformists.[3] In the panic of the "Popish Plot" in 1678 he exhibited a saner judgment than most of his contemporaries and a conspicuous courage. On the 6th of December he protested with three other peers against the measure sent up from the Commons enforcing the disarming of all convicted recusants and taking bail from them to keep the peace; he was the only peer to dissent from the motion declaring the existence of an Irish plot; and though believing in the guilt and voting for the death of Lord Stafford, he interceded, according to his own account,[4] with the king for him as well as for Langhorne and Plunket. His independent att.i.tude drew upon him an attack by Dangerfield, and in the Commons by the attorney-general, Sir W. Jones, who accused him of endeavouring to stifle the evidence against the Romanists. In March 1679 he protested against the second reading of the bill for disabling Danby. In 1681 Anglesey wrote _A Letter from a Person of Honour in the Country_, as a rejoinder to the earl of Castlehaven, who had published memoirs on the Irish rebellion defending the action of the Irish and the Roman Catholics. In so doing Anglesey was held by Ormonde to have censured his conduct and that of Charles I. in concluding the "Cessation," and the duke brought the matter before the council. In 1682 he wrote _The Account of Arthur, Earl of Anglesey ... of the true state of Your Majesty's Government and Kingdom_, which was addressed to the king in a tone of censure and remonstrance, but appears not to have been printed till 1694.[5] In consequence he was dismissed on the 9th of August 1682 from the office of lord privy seal. In 1683 he appeared at the Old Bailey as a witness in defence of Lord Russell, and in June 1685 he protested alone against the revision of Stafford's attainder.

He died at his home at Blechingdon in Oxfordshire on the 26th of April 1686, closing a career marked by great ability, statesmanship and business capacity, and by conspicuous courage and independence of judgment. He ama.s.sed a large fortune in Ireland, in which country he had been allotted lands by Cromwell.