Classification of Ranales: 9 Families | Dicotyledonae

In this article we will discuss about the classification of Ranales. According to Engler, Ranales consists of nine families:- 1. Nymphaeaceae 2. Ceratophyllaceae 3. Berberidaceae 4. Ranunculaceae 5. Menispermaceae 6. Magnoliaceae 7. Annonaceae 8. Myristicaceae 9. Lauraceae.

Family # 1. Nymphaeaceae:

Nymphaeaceae are annual or perennial aquatic herbs, often rhizomatous. Leaves are floating or sub­merged, rarely raised above water-surface, simple or deeply incised, peltate or cordate, usually long petioled; petiole with many air spaces. Flowers solitary usually on a long scape, regular, bisexual, hypogynous or peri- or epigynous, spirocyclic or rarely cyclic, usually large and showy.

Perianth usually differentiated into calyx and corolla, with a gradual transition from sepals to petals and petals to stamens; sepals 3-6, petals 3- many; perianth segments often adnate to torous. Stamens 3-6 or numerous, free; filaments petaloid; anther lobes remote.

Carpels 3-many, fused to form a multilocular ovary or free and often sunk in an enlarged spongy thalamus; ovary superior or in­ferior or semi-inferior; ovules 1-many, parietal. Fruit a spongy berry or a follicle or an aggregate of achenes. Seeds often arillate, with endosperm and perisperm; embryo straight with fleshy cotyledons.

Calcium oxalate crystals are present in cells of some genera and stellate hairs are found in the air spaces. Laticiferous vessels also occur. The vascular bundles are closed and scattered like the Monocotyledons. The xylem is very reduced and with little lignified elements. The stomata are of ranunculaceous type and are found on the upper surface.

The stamens in Nymphaea and Victoria are laminar, flat and broad and without distinction between anthers and filament; the anthers are provided with sterile apicular appendages. The anther cells are deeply sunk in the lamina. The transitional forms between stamens and petals are very clear.

The petals and stamens are arranged in a spiral manner. Such conditions prove the primitiveness of Nymphaea and allied genera. In Euryale and Barclaya anther and filament are well-differentiated and there is no sterile appendage.

In Cabomba and Brasenia the flowers are trimerous and the floral parts are arranged in a cyclic manner. Calyx and corolla are quite distinct; stamens 6 or more, carpels 3-6, free, hypogynous. Nelumbo hits a spirocyclic arrangement of the parts and the petals gra­dually pass into stamens.

Carpels are free and sunk in a spongy elongated obconic thalamus, raised above the perianth and androecium. In Nymphaea and Euryale there are many carpels arranged in a ring and fused together; the ovary is inferior in Euryale but semi-inferior in Nymphaea.

Depending on the floral characters the family is subdivided into 3 sub-families, viz.:

1. Cabomboideae: Cabomba, Brasenia.

2. Nelumboideae: Nelumbo.

3. Nymphaeoideae: Nymphaea, Nuphar, Victoria, Euryale and Barclaya.

The family with 8 genera and about 80 species are distributed in the temperate and tropical parts of the world. Nelumbo mcifera Gaertn is the lotus flower of India and other parts of Asia, occurring also in Egypt. Euryale ferox Salisb is found in eastern parts of India and in China.

Brasenia schreberi Gmel is found in Assam. Nymphaea comparatively a large genus is distributed in many countries and several species are found in India, e.g. N. stellata Willd., N. nouchaii Burm.f.

V. regia Lindl of the amazon-country is cultivated in India and many other tropical countries for the large flowers and very large orbicular leaves more than a mtr. across. The family is of little economic importance. The seeds of Euryale ferox and of several species of Nymphaea are edible. A few are considered to have medicinal value.

Nymphaeaceae as described above is not considered to be a single family by many taxonomists of the present day. Hutchinson splits the family into Nymphaeaceae and Cabombaceae both of which he includes in Ranales and Cronquist splits it into Nymphaeaceae and Nelumbonaceae and places them in a new order Nymphaeales along with Ceratophyllaceae.

Takhtajan also keeps Nymphaeales as a distinct order and splits the family Nymphaeaceae (sensu lato) into Nymphaeaceae, Cabombaceae, Barclayaceae and Nelumbonaceae, the first three families being included in Nymphaeales along with Ceratophyllaceae and the 4th family in a new monotypic order Nelnmbonales.

Takhtajan keeps Nymphaeales in the subclass Magnoliidae and Nelumbonales in the subclass Ranonculidae. This means that according to Takhtajan the genera included under the family Nymphaeaceae as understood by Engler are not at all related to each other “but are so different in their characters that they should be placed in different families and orders and even in different subclasses of the Dicotyledonae.

Family # 2. Ceratophyllaceae:

Ceratophyllaceae is a submerged fresh-water aquatic rootless herbs with slender stem and branches, the lower end of the stem is often embedded in mud and the branches modified into’ rhizoids. Leaves are whorled, linear and bifurcate, sessile; lobes filiform, acuminate, minutely toothed, britde; whorls much crowded near the apex of branches; stipules absent.

Flowers are usually solitary at each node, rarely 1 or more lateral abortive flowers are present indicating the presence of a reduced inflorescence; monoecious, male and female flowers at different nodes, rarely at the same node. Flowers minute, sessile, with one whorl of perianth. Perianth segments 10-16, narrow, subvalvate, 2-fid, sepaloid, often called involucre of bracts.

Stamens 10-20, spirally arranged on a convex recep­tacle; filaments very short, anthers extrorese, 2-celled, cells deeply embedded, connec­tive extending at the apex or cuspidate; pollen large nearly smooth, thin-walled, acolpate.

The pistillate flower with a single carpel; ovary superior, sessile, 1-celled with 1 pendulous orthotropous ovule; style subulate, stigmatic on one side. Fruit a small ovoid or ellipsoid nutlet, slightly compressed, terminated by the persistent style, spur­red on either side, sometimes narrowly winged; seed with scanty endosperm or endos­perm absent; embryo large, straight; cotyledons thick.

The tips of branches often become much thickened and break off and fall to the mud where they he till the end of winter when they germinate and grow to new plants. The vascular bundles have reduced xylem and phloem and mechanical cells are lacking. The single ovule is the result of reduction from many or a laminar type of placenta is evidenced from the vascular supply to the ovule.

The plants of the family are herbaceous; the flowers are unisexual, carpel and ovule reduced to one. The family thus possesses some advanced characters.

But the spirocyclic, flower-stamens numerous and free, anther cells long and deeply embedded in the tissue of the microsporophyll, elongated connective, placentation modified laminar type and somewhat recurrent stigma are characters that indicate that the family is a primitive one and is allied to Nymphaeaceae.

It is a small family with a single genus and 3 species, cosmopolitan in its distribu­tion in fresh water lakes. Ceratophyllum demersam Linn. is common in lakes all over India and is often cultivated to feed the carps and protecting the spawns. The plant has no other use.

Family # 3. Berberidaceae:

Berberidaceae are shrubs or small trees or rhizomatous herbs; the wood is yellow. Leaves are simple or pinnate, alternate, often crowded near apex. Inflorescence is racemose or cymose, often umbellate; rarely flowers solitary. Flowers are bisexual, actinomorphic, trimerous or bimerous. Sepals 3, free, caducous; petals in one or more whorls of 3 segments each, free; the inner whorls are usually nectaries.

The stamens are 6-18, free, in two or more whorls of 3 members in each; the outer stamens are antipetalous; anthers introrse, opening by valves. Ovary of 1 carpel, superior; ovules many or few on ventral suture; style very short; stigma sub-sessile, large and disc-like. Fruit a berry, rarely capsule or achene; seed with copious endosperm and small embryo.

In Berberis 2 types of branches develop, the long branches have thorns which are the modified leaves in the axil of which the short branches come out with simple leaves and the racemes. The terminal flower of the raceme is often pentamerous. ‘Mahonia has imparipinnate leaves crowded near the apex of the branches.

Flowers are dimerous in Epimedium, and have the petals spurred. In this genus the fruit is a capsule. Podo­phyllum has a sympodial rhizome bearing usually 2 large more or less orbicular leaves and a single flower. In the flower of Achlys there is no perianth.

From a study of flower anatomy Eames states that the gynoccium in Berberidaceae is made up of 2-3 united carpels of which one is functional while the others are abortive. The carpels are obliquely and spirally arranged. In many genera the vascular bundles are scattered and in other genera they are in a ring but wide apart with broad medullary rays.

The stomata in Berberidaceae is Ranunculaceous type and the seed germination is similar in Berberidaceae and Ranunculaceae. Some genera in Ranunculaceae have rhizome like that of Podophyllum of Berberidaceae.

Many free stamens, superior ovary, small embryo are other characters by which a relationship is established between Berberidaceae and Ranunculaceae. Affinity with Lauraceae is also close as is evidenced by the valvular dehiscence of the anthers.

The family consists of 12 genera and about 400 species distributed mainly in the temperate regions. It is represented in India by several species of Berberis in the hills and a few Mahonia and Podophyllum.

A few species of Berberis, e.g. B. lycium Royle, B. vulgaris Linn. etc. have medicinal value. The rhizome of Podophyllum yields a resin and an alkaloid—berberine used in medicine. An yellow dye is obtained from the wood of Berberis and Mahonia used by Buddhist monks to colour their garments.

Family # 4. Ranunculaceae:

Ranunculaceae are annual or perennial herbs, often shrubs or climbers, a few are aquatics; the pere­nnials have rhizomes or tuberous roots, the rhizome issympodial; acrid juice is present in some cases.

Leaves are radical or cauline, usually alternate, simple or pinnately or palmately compound or decompound, entire or variously sected, pinnately or palrhately nerved, petiole usually sheathed at the base, exstipulate; in climbing plants petioles and petiolules often c oiling round the support.

Flowers in cymose or racemose inflores­cences or solitary, axillary or terminal, hermaphrodite, very rarely unisexual, usually regular, hypogynous, usually with a prominent convex receptacle and spiral, spirocyclic or cyclic arrangement of parts. Perianth of one or two whorls, similar or differen­tiated into calyx and corolla.

Sepals 5, free, caducous, petaloid, often a few produced into spurs, rarely sepals absent. Petals 5 or more, often spurred. Stamens usually numerous, free, spirally arranged; anthers extrorse, dehiscing by longitudinal slits. Nectaries usually present, formed by the modified outer whorl of stamens or by the modified petals.

Carpels many, free, superior, each with one or more, erect or pendulous ovules on ventral suture; styles long or short, with simple stigma; often carpels coherent to form a compound and multilocular ovary with free styles: ovules anatropous, when many usually in 1-3 series. Fruit an etaerio of follicles or achene’s with persistent styles, rarely capsular or berry. Seeds with a small embryo and copious oily endosperm.

Floral formula in the case of Ranunculus is as follows:

Species of Paeonia are tall shrubs while Clematis, Naravelia and Atragene are climbing shrubs. In the former the petioles and petiolules coil round the support while in the latter the leaf-rachis ends in a tendril. Leaves of Thalictrum are decompound and large. Much variation is noticed in the floral parts.

Usually the flowers are regular, but Del­phinium, Aconitum, etc. have zygomorphic flowers. Flowers are bisexual as a rule but unisexual in Thalictrum. An involucre of 3 bracts occurs in Anemone, Nigella, Eranthis etc. Sepals are often petaloid and are called tepals, e.g. Anemore, Caltha, etc. Petals may be absent as in Clematis, Isopyrum, etc.

In Caltha and Helleborus sepals and petals are spirally arranged but in most cases they are in whorls, the stamens and the carpels are, however, generally arranged spirally. The posterior sepal and the petals in Delphinium are spurred. The petals in Aquilegia are spurred and store honey. The outer stamens in most cases are modified into nectaries and in some cases it is the petals that turn into hoftey-leaves.

The carpels are usually free and many but only 1 in Ac tea and in some species of Del­phinium. In Nigella 5-12 carpels are more or less completely united to form a multilocular ovary.

Ovule is solitary in each carpel but more than one ovule occurs in each carpel or ovary-chamber in case of some genera, e.g. Aconitum, Nigella, Paeonia etc. Fruits are follicular in Caltha, Delphinium, etc., capsule in Nigella, achenes in Clematis, Ranun­culus, etc. and berry in Actea.

The germination is epigeal. The cotyledons have stalks which in some genera are united in a tube. The plumule pierces the tubes laterally as in Monocotyledons. In Clematis the germination is hypogeal. In Ranunculus ficaria and in Eranthis two cotyledons are united to form a single cotyledon.

In most herbaceous species in the family the vascular bundles are closed with ‘V’ shaped xylem. The bundles are scattered or in more than one ring.

These characters, viz. tubular sheath of the cotyledons, union of 2 cotyledons, sheathed leaf- bases, closed vascular bundles, scattered arrangement of vascular bundles; copious endosperm and small embryo in the seed indicate that the Monocotyledons might have originated from Ranunculaceae.

The family is a fairly large one having about 1500 species (2000 according to Cronquist) in 35 genera.

These are mostly found in the temperate parts of the world and in India many species are found to grow in the Himalayas, e.g. Aconitum, Delphinium, Thalictrum, Anemone, Caltha, etc. while a few Clematis, Naravelia zeylanica DC, Ranunculus sclerotus Linn. etc. grow in the plains. Nigella sativa Linn, is cultivated for the seeds.

Some species have acrid juice often strong enough to cause blister on the skin and some have poisonous alkaloids. Few are medicinal, e.g. Aconitum napellus Linn., Anemone Pulsatilla Linru Delphinium slaphisagria Linn. (Stavesacree seeds), Cimicifuga racemosa Nutt. (Black snake root), Hydrastis canadens Linn. (Hydrastic rhizome), etc. Cumin seeds are obtained from Nigella sativa Linn, used as a condiment.

Many species of Delphinium, Clematis, Anemone, Aquilegia, Paeonia etc. have beautiful flowers and are culti­vated as garden annuals.

Ranunculaceae is one of the primitive families according to Hutchinson and most other botanists including Takhtajan and Cronquist although Engler, Rendle and a few others consider it to be fairly advanced. Spiral arrangement of floral parts, numerous free stamens and carpels and presence of copious endosperm indicate that the family is not of recent origin.

Xylem vessels with simple pits also support this view. The stomata arc without subsidiary cells and are known as Ranunculaceous type of stomata. The pollen is uniarperturate and this fact also points to its primitiveness. Many workers in taxonomy consider the family Ranunculaceae to be a natural group.

Rendle subdivides the family into 3 tribes as noted below:

Helleboreae:

Ovules arranged in 2 rows along the ventral suture of carpels; fruit a cluster of folliclcs or rarely a berry.

Anemoneae:

Solitary ovule at the base of ventral suture of carpcls; fruit a cluster of achene.

Paeonieae:

Ovules as in Helleboreae; a fleshy disc present around the carpels; the outer integument is much larger; follicles with fleshy walls.

The tribe Paeonieae is segregated by Hutchinson and others as a separate family Paeoniaceae. Hutchinson also raises the tribe Helleboreae to the rank of a family e.g. Helleboraceae but most others prefer to retain it under Ranunculaceae.

The genus Hydrastis having flowers without petals and without nectaries is an anomalous genus and is placed under Berberidaceae (or Podophyllaceae) by many taxonomists. Takhta­jan places it under a new family Hydrastiaceae close to Ranunculaceae.

Paeoniaceae as a distinct family has the following characters:—Herbs or rarely undershrubs with a stout perennial rootstock or tubers; stem-base covered with scale like sheaths. Leaves alternate, petiolate, twice ternate, segments pinnately nerved. Flowers solitary or panicled, hermaphrodite, slightly irregular, usually large and showy. Sepals 5, free, subfoliaceous, unequal, persistent, imbricate.

Petals usually 5, or sometimes 6-10, orbicular, subequal, imbricate. Stamens numerous, free, centrifugal and spirally arranged; anthers 2-locular, extrorse, opening by slits lengthwise. A fleshy disc surrounds the carpels sometimes almost enclosing them.

Carpels 5 or fewer, free, fleshy, arcuate-divergent; stigma sessile, thick, falcate, 3-lipped. Fruit a cluster of divergent follicles, dehiscing by the adaxial suture; seeds globose, arillate, shining; aril umbonate; endosperm fleshy copious; embryo small.

Hutchinson includes Paeoniaceae in his Ranales but Takhtajan and Cronquist consider this family closer to Dilleniaceae than to Ranunculaceae and remove it from Ranales (the name changed to Ranunculales).

Family # 5. Menispermaceae:

Menispermaceae is usually woody twiners, rarely erect shrubs. Leaves are alternate, simple or rarely 3-foliolate, exstipulate, rarely palmately lobed, usually palmi-veined. Inflorescence a raceme or cyme or panicle. Flowers are minute, unisexual and dioecious generally acti­nomorphic, cyclic and 2-3-merous.

Sepals and petals each in 2 whorls, usually 3 in each whorl, sometimes 2, very rarely 1; petals usually smaller than sepals; sepals and petals free, imbricate. Male flowers usually with 6 stamens, often 3 and opposite to petals or rarely many, free or variously connate; anthers 2-celled or falsely 4-celled dehiscing longitudinally or transvesely; rudimentary pistils rarely present.

Female flowers with 3-6 free carpels, often carpels more, rarely 2 or 1; ovary superior, ovules 2 in each carpellary chamber, anatropous, one is abortive; placentation parietal; style very short or absent; stigma capitate or discoid, entire or bilobed; a gynophore is often present; staminodes often present. Fruit is an aggregate of drupes or achenes; seeds with or without fleshy endosperm and curved embryo.

The floral formulas may be represented in the following manner:

The flower, however, varies much in this family in different genera. As a rule the flowers are actinomorphic but Cissampelos has zygomorphic flowers. The family is cha­racterised by dioecious plants but monoecious condition is found in Albertia and in some species of Cissampelos.

The number of sepals may be as many as 36, e.g. in Scidotonia, they may be only 4 (2+2), e.g. male flower of Cissampelos parierahinn., and only 1 in the female flower of the same; Pycnarrhena also has 4 sepals.

Petals 4 (2+2) in the staminate flowers of Cissampelos pariera but only 1 in the pistillate flower. Female flower of Scidotonia has no petal. In Anamirta petals absent in both types of flowers. Antiaxis has 2 petals. In Cissampelos the petals of male flowers are connate. Filaments of stamens are usually free but monadelphous in many genera, e.g. Parabaena, Anamirta, Stephania, etc.

In Rhiziocarya there are 5 stamens in 2 whorls, the outer 2 are free while the inner 3 are united into a column. Anthers 2-celled but 1-celled in Antitaxis; dehiscence is .longitudi­nal but transverse in many genera. Usually the carpels are 3 but 6 in Haematocarpus, 9-12 in Tiliacora, 3-6 in Cocculus, solitary in Cissampelos, Stephania and Cyclea.

Gynophore present in Anamirta. Style is 3-6 partite in Stephania, 3-fid or 3-toothed in Cissampelos but simple in other genera. Flowers usually trimerous but in Cissampelos the staminate flower is dimerous while the pistillate flower is unimerous.

In Cyclea also the pistillate flower is unimerous. In Pycnarrhena calocarpa (Kurz) Diels the flower is dimerous. Further, dioecious or monoecious, all genera have unisexual flowers but Cocculus carolinus DC. and Abuta rufescens Aubl. in cultivated condition produce bisexual flowers instead of female flowers.

Plants are twining shrubs but Pycnarrhena calocarpa is erect. Stephania oynantha is an epiphyte.

Anatomy of the stem shows unusual secondary thickening. Meristematic layers are formed outside the original ring of vascular bundles. These meristematic cells produce new vascular bundles while the original cambium ceases to grow. Secon­dary phloem formation is poor and interxylary phloem is mostly present. Vessels usually large and solitary with simple perforations. Wood parenchyma is apotracheal.

The family consists of about 400 species under 70 genera. They are mostly found in the tropical countries. In India it is represented by Cissampelos pareira Linn., Stephania japonica (Thunb.) Miers (Beng. Nimukha), Tinospora cordifolia (Willd.) Miers (Beng. Gulancha), Cocculus hirsutus (Linn.) Diels (Beng. Huyer), etc. In Europe and N. America fossil specimens were discovered from Tertiary beds. This indicates wider distribution of the family in the past.

The family is-of little economic importance. Tinospora cordifolia is used as a febrifuge and a few others have medicinal value.

Menispermaceae is a natural taxon. It appears to be more closely related to Lardizabalaceac than to the other families of the order Ranales.

The apocarpous gynoecium marks it as one of the primitive families although in some other characters it appears to be fairly advanced. Hutchinson placed the family in the order Berberidales while Takhtajan as well as Cronquist places it in Ranunculales wherein both Lardizabalaceae and Menispermaceae are included.

Family # 6. Magnoliaceae:

Magnoliaceae are trees and shrubs, usually evergreen. Leaves are simple, alternate, stipulate; stipules deciduous, large and forming bud-scales, free or adnate to the petiole. Flowers solitary, usually large and showy, actinomorphic, bisexual, rarely polygamous, very rarely unisexual, usually spirocyclic, with an elongated, or convex receptacle.

Perianth seg­ments many, differentiated into calyx and corolla or all petaloid, spirally arranged on the receptacle or in whorls, imbricate. Stamens numerous, free, spirally arranged; fila­ments showing a transition from laminar type to terete filaments and proper anthers; anther lobes 2, introrse, dehiscing longitudinally.

Carpels numerous free spirally arranged on elongated or convex receptacle; ovary superior; ovules 2 or more in each carpel, anatropous, parietal on the ventral suture; rarely carpels are united. Fruit an aggregate of follicles or berries or samaras. Seeds suspended by a long slender funiculus; endosperm copious, oily; embryo small; testa bright coloured.

Although predominantly erect plants, trees or shrubs, climbing plants or scan-dents are also met with, e.g. Schizandra and Kadsura. Sheath-like stipules cover the vegetative bud in most genera but in Drimys, Schizandra, Illicium, etc. stipules are absent. Bisexual flowers occur in most of the genera but flowers are unisexual in Kmeria, Drimys, Schi­zandra, etc.

Carpels are usually free, but in Pachylarnax and Zygogynum they are fused and in Talauma they do so in fruiting. Fruits are mostly follicles but Schizandra has an etaerio of berries, and samaras in Liriodendron and Euptelea.

The floral formula for the family may be expressed as:

The family consists of 12 genera and 230 species with a peculiar distribution with an eastern centre comprising the Indo-Malayan region, S. China, Japan and Australia to the south and western centre in N. E. United States and southwards to Brazil and W. Indies. It is absent in Africa and Europe. But fossil remains were discovered in Tertiary deposits in the Artie Circle, Greenland, Europe and Central N. America.

This suggests a wider distribution in past and it is surmised that during the ice-ages the family migrated southwards and the present distribution of the family is the result of that migration. In India the family is represented by several genera, e.g., Magnolia, Michelia, Manglietia, Schisandra, Talauma and Kadsura. Michelia champaca Linn, is much cultivated in the plains for its fragrant beautiful flowers.

Magnolia Campbelli Hkf. & Th of the East Himalayas is a deciduous tree with large white or pink flowers. Magnolia grandiflora Linn, an American species is also cultivated in India in the plains as well as in the hills at low altitude. Liriodendron tulipifera Linn.—the Tulip tree of America is also cultivated.

A few species are economically important. Liriodendron tulipifera, a tall tree reaching about 70 mtr. in height, is a good timber-tree. Some species of Michelia, Magno­lia, Marigletia, Talauma, Pachylarnax also yield good timber. Illicium verum Hk.f. of S. China is the Star-Anise. An essential oil is obtained from the flowers of Michelia champaca.

The wood possesses vessels which have scalariform perforations with many bars, bordered at the ends or at the middle or completely. Vessels are very long, narrow, thin walled, polygonal in outline and with highly inclined perforation plates.

Some genera have vessel-less wood, e.g. Drimys, Eyosperrnum, Trochodendrotl, etc. Stamens usually have 3 traces, often 5 or 7 although rarely 1 trace also occurs. The marginal placentation of the carpels appears to be a modified laminar plancentation. The stomata have guard-cells accompanied by subsidiary cells parallel to the pore.

Magnotiaceae appears to be closely related to Annonaceae both of which are included In Ranales by Engler and also by Rendle. Both of them consider that the families included in this group are fairly advanced having a well-defined perianth. But accor­ding to subsequent authors these are very primitive having polymerous flowers.

Magnoliaceae is one of the most primitive families among the Dicotyledonae as is evi­dent from floral as well as anatomical characters. Hutchinson, Takhtajan and Cron­quist place Magnoliaceae in a distinct order Magnoliales, the first order among the Dicotyledons.

The elongated floral axis bearing many perianth segments usually spirally arranged, the numerous stamens and carpels, also often acyclic in arrange­ment, indicate a primitive flower.

To have copious endosperm in the seed is also a primitive character. The scalariform pitting of the vessels resembles the xylem of the Mesozoic Cycadeoideae. The vessel-less wood in some genera, being characteristic of the Gymnosperms, also points to primitiveness.

Hutchinson splits the older Mangoliaceae into 6 families, viz. Magnoliaceae, Win- teraceae, Illiciaceae, Schisandraceae, Eupteleaceae and Tetracentraceae based princi­pally on the morphology of the flowers. The cytological findings of Whitaker also support the separation of these families from Magnoliaceae sensustricto.

Some also prefer to seggregate Degeneriaceae as a family distinct from Winteraceae. The distribution of these families, however, throws some doubt as to the validity of such treatment esta­blishing so many smaller families.

Family # 7. Annonaceae:

Annonaceae are trees or shrubs, often scandant or lianas. Leaves are simple, exstipulate, entire, alter­nate. Flowers cauliflorous, i.e., produced on the older woody part of the branches, solitary or often fascicled; regular and spirocyclic, usually bisexual.

Perianth in 3 whorls, each with 3 segments; the outermost whorl is sepal-like with much smaller segments than the inner whorls, valvate, free or connate below; the inner whorls with petal-like segments, similar in the same whorl, often differing in size in different whorls; valvate or imbricate, free.

The receptacle is convex or conical on which numerous stamens and carpels are borne. The stamens are spirally arranged; filaments short, thick; anthers long, extrorse, with a prominent truncate connective.

Gynoecium superior, of many free carpels, spirally arranged on the receptacle, each carpel with 1-many basal or marginal ovules, stipitate; style short or absent; stigma simple. Fruit an etaerio of drupes or berries, rarely follicles, sometimes fused to form a composite fruit. Seeds often arillate, with a small embryo and copious ruminated endosperm.

Floral formula:

The structure of the flower is more or less uniform in the family. On rare cases deviation from the general type is noticed. The Malayan genus Stelechocharpus is dioe­cious. In the African genus Monodora the petals being slightly unequal, the flowers are irregular. In this genus carpels are united to form a unilocular ovary with parietal placentation. In Xylopia the anthers are transversely septate. Anaxogorea has follicular fruits.

The family with about 80 genera and 880 species is distributed in the tropical countries of the world. In India the family is well represented by several species of which Polyalthia longifolia (Sonner) Thaw.—the Debdaru, Artabotrys hexapetala Bhandari —the Kanthali Champa, Desmos dunalii (Hk.f. & Th.) Saff., Cananga odorata (Lamk.) Hk.f. & Th., Goniothalamus cardiopetalus Hk.f. & Th., Miliusa indica Leschen., M. tomen- tosa (Roxb.) Sinclair, Alphonsea lutea Hk.f. & Th., Uvaria hamiltonii Hk.f. & Th. are quite common among the indigenous species.

Annona squamosa Linn, the Custard Apple (Beng. Ata), A. reticulate Linn.—the Bullock’s heart (Beng. Nona) both native of Trop. America are widely cultivated for the edible fruits.

A few species are economically important. Besides the 2 species of Annona men­tioned above, A. cherimolia Mill, and A. muricata Linn, have edible fruits. The fruits of Asimina triloba Dun. are also edible. Polyalthia longifolia, Bocagea laurifolia Bth. & Hk.f., B. virgata Bth. & Hk.f. and Duguetia qutarensis Bth. yield timber. Cananga oil or Macassar oil is obtained from Cananga odorata (Lamk.) Hk.f. & Th.

The family is allied to Magnoliaceae having free floral parts, numerous stamens and carpels and the gynoecium superior. Along with Magnoliaceae it is included in Ranales by Engler and Rendle. Wettstein placed it in his Polycarpicae with Magnoliaceae, Ranunculaceae, etc.

Above authors considered these families to be fairly advanced but the floral characters do not indicate advancement but primitiveness and these families are now considered so by all recent workers. Hutchinson includes Annonaceae in a new order Annonales along with Eupomatiaceae and places this order next to Magnoliales. Eames, Takhtajan and Cronquist keep Annonaceae in Magnoliales.

The family is subdivided into 2 subfamilies and 4 tribes as noted below:

I. Annonoideae:

Carpels free, spirally arranged.

(i) Uvarieae: Leaves distichous; petals imbricate (rarely valvate)—Uvaria, Unona, etc.

(ii) Annoneae: Leaves distichous; petals valvate (rarely imbricate)—Annona, Desmos, Polyalthia, etc.

(iii) Tetramerantheae: Leaves spirally arranged; sepals imbricate (stigma 3-lobed). —1 genus-Tetrameranthus.

II. Monodoroideae:

Carpels united into a unilocular ovary, cyclic arrangement.

(iv) Monodoreae: Placentation parietal,—2 genera, Monodora and Isoloma.

The family resembles the Monocotyledonae by its typically trimerous flowers and a small embryo in copious endosperm.

Family # 8. Myristicaceae:

Myristicaceae are evergreen trees or shrubs, usually aromatic; the inner bark often exuding reddish sap. Leaves are alternate, simple, entire, often with pellucid dots, exstipulate. Flowers unisexual, in monoecious or dioecious plants, in racemose, corymbose, fascicled or in globose heads, actinomorphic and hypogynous. Perianth uniseriate, gamosepalous, tubular or campanulate, 3-lobed; lobes imbricate.

Staminate flower with 3-30 stamens, monadelphous, the staminal column sometimes spread out in the form of a disc; anthers 2-celled, extrorse, distinct or connate, dehiscing longitudinally. Pistillate flower with a superior ovary, monocarpellary, unilocular, with 1 anatropous, basal or parietal ovule; style short or absent.

Fruit is a drupe but splitting along both the ventral and dorsal sutures on maturity. Seed arillate with a small embryo and copious oily and ruminate endosperm; testa hard; aril laciniate or sub-entire, brightly coloured; cotyledons leafy.

The pollens are uniaperturate. The notes are trilacunar. The wood vessels have simple or scalariform perforation plates. The wood parenchyma is paratracheal. Taniniferous ducts are present in the pith. The family with about 300 species under 18 genera is distributed in the tropical region of the Old- and New-World but more in S. E. Asia. It is not represented in India.

Myristica fragrans Houtt. is the source of nutmeg and mace; the mace is the aril while the nutmeg is the seed itself. Both nutmeg and mace have been in use as spices from ancient times and are in great demand. They are reputed also to have medicinal value and the tree is cultivated in Moluccas, the native country, as well as other tropical countries for the seed and its aril.

The family is considered to be closely related to Annonaceae for the trimerous flowers and ruminated endosperm. According to Hutchinson it is closet- to Lauraceae and he places it in his Laurales while Annonaceae is placed by him in Annonales.

Although the flower shows some advanced characters, viz., united sepals, united filaments and monoecious or dioecious character, the family is considered to be a primitive one as is evidenced by wood anatomy, pollen character, presence of many stamens, small embryo and copious endosperm.

Family # 9. Lauraceae:

Lauraceae are trees and shrubs, usually with aromatic bark and foliage; rarely parasitic twining herbs. Leaves are simple, alternate, rarely, opposite, usually entire, penninerved rarely with 3 prominent nerves from the base, coriaceous, glandular punctate, exstipulate.

In­florescence is a raceme, spike or umbel, often a panicle, axillary or sub-terminal. Flowers bisexual, rarely unisexual and the plants dioecious, actinomorphic, trimerous, small and inconspicuous.

Perianth in 2 whorls of 3 similar segments in each, greenish, yellowish or white; segments connate near the base, imbricate, usually persistent.

The androecium consists of 4 trimerous whorls; stamens adnate to perianth tube; the innermost whorl or the inner 2 whorls reduced to staminodes; rarely there are only 2 whorls, the outer of fertile stamens and inner of staminodes; filaments are usually free from each other; anthers basifixed, 2- or 4-celled, introrse, but those of the 3rd whorl when fertile extrorse, dehiscing by valvular flaps opening upwards; the filaments of the 3rd whorl usually bearing a pair of glandular protuberances at the base; the valves are superposed when the anther is 4-celled.

Ovary superior, 1-celled, with a solitary anatropous ovule pendulous from the wall of the ovary; style 1, stigma entire or 2-3-lobed. Fruit a drupe or berry, usually surrounded at the base by the persistent and often enlarged perianth tube; the receptacle is often elongated. Seed with a large straight embryo and no endos, perm; cotyledons large and fleshy.

The floral formula may be represented as:

The ovary is monocarpellary but the often trilobed stigma suggests that originally carpels were 3 of which 2 became abortive. All plants are erect and with a woody perennial habit only exception is the genus Cassytha the species of which are herbaceous twiners.

Further the species of Cassytha are total parasites with scale-like leaves or leaves altogether absent. In Sassafras the leaves are lobed; in other genera the leaves are entire.

Flowers are her­maphrodite but in Laurus they are unisexual. Actinodaphne and Litsaea also have unisexual flowers and are dioecious. Anthers 2- celled in Cassytha, Cryptocarya, Beilschmedia etc. but 4-celled in Cinnamomum, Phoebe, Litsaea etc. The cells are parallel but in Nectandra the 4 cells are arranged in an arc.

The family contains about 1,100 species in 45 genera. They are found mostly in E. Asia, some extending northwards to Japan and a few are Australian. In the New World, species of this family are found in Chili and Brazil in south and up to Canada in the north.

A few species occur in Africa while Laurus nobilis Linn, is found in Medi­terranean region and in W. Asia. It is well represented in India by several species of Cinnamomum, Litsaea, Lindera, Beilschmedia etc.

A few species are economically important of which Cinnamomum camphora Linn, is well known as the source of natural camphor. C. zeylanicum Breyn. of India and Sri Lanka yields the cinnamon bark. C. tamala Nees & Eber. is the Tamala-tree of Sanskrit literature.

The leaves of this tree as well as those of C. zeylanicum and a few other species of the genus are used as spice and are known as Tejpatra. Persea americana Mill, produces the Avocado pear.

Sassafras albidum Nees is an important medicinal plant. Many species yield good timber which is not attacked by insects and boxes prepared from th6 planks are used to keep costly clothing’s. The wood of Sassafras and Cinnamomum are scented.

Pax divided the family into 2 tribes:

Perseoideae: anthers 4-celled, dehiscing by 4 valves.

Lauroideae: anthers 2-celled, dehiscing by 2-valves.

The family is related to Annonaceae and Myristicaceae having trimerous flower and many stamens. It is also related to Magnoliaceae where the receptacle enlarges in fruit.