to a Convocation Man (8vo, 1697); Atterbury, The Rights, Powers
and Privileges of an English Convocation stated and vindicated in
answer to a late book of Dr Wake’s (8vo, 1700); Burnet, Reflections
on a Book intituled The Rights, Powers and Privileges of an English
Convocation stated and vindicated (4to, 1700); Kennet, Ecclesiastical
Synods and Parliamentary Convocations of the Church of England
historically stated and justly vindicated from the Misrepresentation
of Mr Atterbury (8vo, 1701); Atterbury, The Power of the Lower
House of Convocation to adjourn itself (4to, 1701); Gibson, The Right
of the Archbishop to continue or prorogue the whole Convocation (4to,
1701); Kennet, The Case of the Praemunientes (4to, 1701); Hooper,
The Narrative of the Lower House vindicated from the Exceptions of a
Letter, intituled The Right of the Archbishop to continue or prorogue
the Convocation (4to, 1702); Atterbury, The Case of the Schedule
stated (4to, 1702); Gibson, The Schedule Reviewed, or the Right of
the Archbishop to continue or prorogue the whole Convocation, cleared
from the Exception of a late Vindication of the Narrative of the Lower
House, and of a Book intituled The Case of the Schedule stated (4to,
1702); Hody, A History of the English Councils and Convocation,
and of the Clergy’s sitting in Parliament (8vo, 1702); Wake, The
State of the Church and Clergy of England in their Councils, Synods,
Convocations, Conventions, and other Public Assemblies, occasioned
by a book intituled The Rights, Powers and Privileges of an English
Convocation (fol., 1703); Burnet, History of His Own Time (2 vols,
folio, 1734), re-edited by Dr Martin J. Routh (6 vols. 8vo, 1833);
Hallam, Constitutional History of England (3 vols. 8vo, 1832); Cardwell,
Documentary Annals of the Reformed Church of England (2 vols.,
1839); Cardwell, A History of Conferences and other Proceedings
connected with the revision of the Common Prayer (8vo, 1841); Cardwell,
Synodalia, a Collection of Articles of Religion, Canon and Proceedings
of Convocation in the Province of Canterbury (2 vols. 8vo,
1842); Lathbury, A History of the Convocation of the Church of England
(2nd ed., 8vo, 1853); Trevor, The Convocation of the two Provinces
(8vo, 1852); Pearce, The Law relating to Convocations of the
Clergy (8vo, 1848); Synodalia, a Journal of Convocation, commenced
in 1852 (8vo); The Chronicle of Convocation, being a record of the
proceedings of the Convocation of Canterbury, commenced in 1863
(8vo). (T. T.; T. A. I.)
CONVOLVULACEAE, a botanical natural order belonging to
the series Tubiflorae of the sympetalous group of Dicotyledons.
It contains about 40 genera with more than 1000 species, and is
found in all parts of the world except the coldest, but is especially
well developed in tropical Asia and tropical America. The most
characteristic members of the order are twining plants with
generally smooth heart-shaped leaves and large showy white or
purple flowers, as, for instance, the greater bindweed of English
hedges, Calystegia sepium, and many species of the genus Ipomaea,
the largest of the order, including the “convolvulus major” of
gardens, and morning glory. The creeping or trailing type is a
common one, as in the English bindweed (Convolvulus arvensis),
which has also a tendency to climb, and Calystegia Soldanella,
the sea-bindweed, the long creeping stem of which forms a sand-binder
on English seashores; a widespread and efficient tropical
sand-binder is Ipomaea Pes-Caprae. One of the commonest
tropical weeds, Evolvulus alsinoides, has slender, long-trailing
stems with small leaves and flowers. In hot dry districts such
as Arabia and north-east tropical Africa, genera have been
developed with a low, much-branched, dense, shrubby habit,
with small hairy leaves and very small flowers. An exceptional
type in the order is represented by Humbertia, a native of
Madagascar, which forms a large tree. The dodder (q.v.) is a
genus (Cuscuta) of leafless parasites with slender thread-like
twining stems. The flowers stand singly in the leaf-axils or form
few or many flowered cymose inflorescences; the flowers are
sometimes crowded into small heads. The bracts are usually
scale-like, but sometimes foliaceous, as for instance in Calystegia,
where they are large and envelop the calyx.
The parts of the flower are in fives in calyx, corolla and stamens, followed by two carpels which unite to form a superior ovary. The sepals, which are generally free, show much variation in size, shape and covering, and afford valuable characters for the distinction of genera or sub-genera. The corolla is generally funnel-shaped, more rarely bell-shaped or tubular; the outer face is often marked out in longitudinal areas, five well-defined areas tapering from base to apex, and marked with longitudinal striae corresponding to the middle of the petals, and alternating with five non-striated weaker triangular areas; in the bud the latter are folded inwards, the stronger areas being exposed and showing a twist to the right. The slender filaments of the stamens vary widely, often in the same flower; the anthers are linear to ovate in shape, attached at the back to the filament, and open lengthwise. Some importance attaches to the form of the pollen grains; the two principal forms are ellipsoidal with longitudinal bands forming the Convolvulus-type, and a spherical form with a spiny surface known as the Ipomaea-type. The ovary is generally two-chambered, with two inverted ovules standing side by side at the inner angle of each chamber. The style is simple or branched, and the stigma is linear, capitate or globose in form; these variations afford means for distinguishing the different genera. The fruit is usually a capsule opening by valves; the seeds, where four are developed, are each shaped like the quadrant of a sphere; the seed-coat is smooth, or sometimes warty or hairy; the embryo is large with generally broad, folded, notched or bilobed cotyledons surrounded by a horny endosperm. Cuscuta has a thread-like, spirally twisted embryo with no trace of cotyledons.
 | |
| Convolvulus sepium, slightly reduced. | |
| 1. Flower cut vertically. | 4. Embryo taken out of seed. |
| 2. Fruit, slightly reduced. | 5. Horizontal plan of arrangement of flower. |
| 3. Seed cut lengthwise showing embryo. | |
The large showy flowers are visited by insects for the honey which is secreted by a ring-like disk below the ovary; large-flowered species of Ipomaea with narrow tubes are adapted for the visits of honey-seeking birds.
The largest genus, Ipomaea, has about 400 species distributed throughout the warmer parts of the earth. Convolvulus has about 150 to 200 species, mainly in temperate climates; the genus is principally developed in the Mediterranean area and western Asia. Cuscuta contains nearly 100 species in the warmer and temperate regions; two are native in Britain.
The tubers of Ipomaea Batatas are rich in starch and sugar, and, as the “sweet potato,” form one of the most widely distributed foods in the warmer parts of the earth. Several members of the order are used medicinally for the strong purging properties of the milky juice (latex) which they contain; scammony is the dried latex from the underground stem of Convolvulus Scammonia, a native of the Levant, while jalap is the product of the tubercles of Exogonium Purga, a native of Mexico. Species of Ipomaea (morning glory), Convolvulus and Calystegia are cultivated as ornamental plants. Convolvulus arvensis (bindweed) is a pest in fields and gardens on account of its wide-spreading underground stem, and many of the dodders (Cuscuta) cause damage to crops.
CONVOY (through the Fr. from late Lat. conviare, to go along with, from Lat. cum, with, and via, way; “convey” has the same ultimate origin [see Conveyance], neither word being
