Classification of Liliiflorae: 4 Families | Monocotyledoneae

In this article we will discuss about the Classification of Liliiflorae. According to Engler and Prantl, Liliiflorae consists of four families:- Juncaceae 2. Liliaceae 3. Amaryllidaceae 4. Iridaceae.

Family # 1. Juncaceae:

Juncaceae are annual or perennial herbs, rarely undershrubs of marshy places with creeping sympodial rhizomes and hairy roots; rarely plants tall and Yucca-like, e.g. Prionium. Stem usually angled, with a soft pith. Leaves are usually in a basal tuft, linear, filiform or cylindric or flat and dorsiventral, sheathing at the base; rarely sometimes reduced to sheath only.

The inflorescence is various; usually the small flowers are aggregated in condensed head-like cymes or it is a panicle of racemes or corymbs or false umbeles; rarely flowers solitary; bracts and bracteoles present.

Flowers regular, bisexual or often uni­sexual and dioecious, hypogynous. Perianth in two or one whorl of 3 members in each; segments glumaceous with scarious or coriaceous margins, free and imbricate; rarely perianth petaloid.

Stamens 6 in two whorls, inserted on the base of perianth segments; filaments triquetrous, slender; anthers basifixed, introrse, opening by longitudinal slits; pollen in tetrads. Ovary superior, trilocular with axile placenta don or unilocular with parietal placentation; ovules many or few, rarely one and basal; style with 3 plumose stigmas which are often twisted to the right; often styles 3.

Fruit a loculicidal capsule with small and often appendaged seeds; embryo straight, endosperm mealy. Flowers are anemophyllous, some with coloured perianth are however pollinated by insects. The floral formula in case of ♂ flowers is P₃₊₃ A_{3+3 (or 3 + 0)} G₍₃₎.

The family contains a little over 300 species in 8 genera occurring in cool damp places in temperate countries with a few even in antartic region. In India the family is represented by several species of Juncus and a few of Luzula at high elevations of the Himalayas and hills of eastern India. J. bufonius Linn, and J. prismatocarpus R. Br. come down to the plains of Bihar and Bengal.

Only a few plants of this family are of economic importance. Fibres obtained from Juncus textilis Buchen. and species of Marsippospermum and Prionium are used in weaving mats, making hats, chair-seats and cushions. Some species of Luzula have medicinal properties.

Juncaceae has been included in the order Liliiflorae by Engler because of the general plan of the flower having 6 perianth segments in 2 whorls, 6 stamens in 2 whorls and superior trilocular ovary.

But the nature of the perianth appears to be a strong character to remove this family from Liliiflorae and place it in a distinct order Joncales with Thurniaceae and also with Restionaceae and Centrolepidaceae according to Hutchinson.

Hutchinson derives Juncales from Liliales but states that it has closer affinities with Cyperales and Graminales and includes these three orders in Division Glumiflorae.

Both Takhtajan and Cronquist agree to include Juncaceae and Thurmiaceae in Juncales which order according to them has been derived from a stock that gave rise to Commelinales rather than Liliales. They also think that Juncaceae is closely allied to Cyperaceae.

Family # 2. Liliaceae:

Liliaceae are generally perennial herbs with an underground rhizome or bulb or corm: the rhizome is sympodial; sometimes shrubby, often climbing or arbore scent; branches often modified into cladodes.

Leaves are radical or cauline, sessile and sheathed at the base or petiolate, linear or lanceolate or ovate, leathery or very thick or soft and fleshy; often leaves are converted into scales subtending the cladodes; veins obscure in thick leaves, otherwise prominent.

Racemes simple or branched, often condensed into an umbel, each flower sub­tended by a bract; or flowers solitary. Flowers hermaphrodite, very rarely unisexual, hypogynous rarely perigynous, regular or rarely zygomorphic. Perianth in 2 whorls of 3 segments each; segments usually all similar and petaloid or rarely the outer sepaloid, free and imbricate, rarely connate below.

Stamens 6, opposite perianth segments; filaments free or rarely connate; anthers dehiscing longitudinally or by apical pores; rarely stamens fewer. Ovary superior or semi-inferior, trilocular or rarely 2, 4 or 5- locular; ovules usually many in 2 rows on axile placentation, anatropous.

Fruit usually a capsule, loculicidal or septicidal, rarely fruit is a berry; seed with fleshy or hard endosperm. Polyembryony has been observed in certain cases. Flowers are pollinated by insects attracted by brightly coloured perianth, nectar and odour.

The usual floral formula is as follows:

The family is a large one with about 2500 species under 250 genera distributed almost all over the world. The plants show a great range of variations in vegetative as well as floral parts. The underground stem may be a bulb as in Lilium, Tulipa, a corm as in Colchicum and rhizome as in Gloriosa.

The majority of the plants are herbs but a few genera like Gloriosa, Asparagus, etc. are climbers, and shrubby plants often attaining the size of trees, e.g. Dracaena, Cordyline, etc. In the last group forming the subfamily Dracaenoideae secondary growth in stem occurs by the formation of successive concentric rings of vascular bundles in the ground tissue.

In some genera the branches are modified into cladodes arising from the axil of scale-leaves, broad and leaf-like as in Ruscus, needle-like as in Asparagus. Leaves are clustered on top of the bulbs or enclosing them or scattered over stem and branches or whorled near the apices; soft and fleshy or thick and leathery or thin and papery; linear or with a distinct lamina and petiole.

The inflorescence ter­minates a leafless scape or on leafy stem and branches or may be axillary; it is of racemose type, simple or paniculatc, often forming a false or true umbel; soli­tary flowers occur also in many genera. In Ruscus the clusters of flowers arise from the surface of the cladodes or from the margins.

Flowers are bisexual in most genera but unisexual in Ruscus, Smilax, etc. Perianth segments are usually all similar or the outer calyx-like and different from those of the inner whorl. Stamens are free but rarely united in a column as in Ruscus, Heterosmilax, Tricyritis, etc., free from the perianth or adnate to it; connective rarely prolonged; dehiscence of anthers by longitudinal slits or by apical pores.

Ovary is usually superior but semi-inferior ovary is found in the subfamilies Ophiopogonoideae (Mondoideae) and Aletroideae-, ovary is syncarpous but carpels are almost free to the base in Petrosavia and Protolirion. Fruit is a capsule but in many genera it is a berry.

Petrosavia is saprophytic while Protolirion is a root-parasite.

The family is subdivided into 11 subfamilies by Krause following the treatment of Engler as given below:

I. Sub. f. Melanthioideae:

Rhizome or bulb present; leaves radical or cauline; inflorescence terminal; ovary superior; fruit a capsule:—Tofieldia, Gloriosa, Colchicum, etc.

II. Sub. f. Asphodeloideae:

Rhizome with radical leaves or with aerial leafy stem; inflorescence terminal; ovary superior; fruit a capsule or berry:—Asphodelus, Chloro- phytum, Anthericum, etc.

III. Sub. f. Herrerioideae:

Twiner with underground tuber; leaves tufted; ovary superior; fruit capsular:—Herreria (singlegenus).

IV. Sub. f. Allioideae:

Short rhizome or bulb; inflorescence on leafless scapc, an umbellate cyme enclosed by a pair of membranous spathes; ovary superior; fruit capsular:—Allium, Gagea, Gilliesia, etc.

V. Sub. f. Lilioideae:

Bulbous plants; inflorescence racemose, terminal; leaves radical or cauline; ovary supe­rior; fruit capsular:—Lilium, Tulipa, Scilla, Urginea, Hyacinthus, etc.

VI. Sub. f. Dracaenoideae:

Erect stem; leaves usually clustered near the apex of stem and branches, leathery or very thick but not fleshy; inflorescence terminal; ovary superior; fruit berry or capsule:—Yucca, Dracaena, Cordyline, San- sevieria, etc.

VII. Sub. f. Asparagoideae:

Rhi­zome present; aerial stem often climbing bearing cladodes; inflorescence terminal or axillary; ovary superior; fruit berry or capsule:—Asparagus, Ruscus, Convallaria, Paris, Trillium, etc.

VIII. Sub. f. Ophiopogonoideae (Mondoideae):

Rhizome short; leaves radical or cauline; inflorescence terminal or axillary; ovary semi-inferior; ovules only 2 in each cell; fruit capsule or berry:—Ophiopogon (Mondo), Peliosanthes, etc.

IX. Sub. f. Aletroideae:

Rhizome short; leaves radical, lanceolate; inflorescence terminal; perianth segments connate; ovary semi-inferior; fruit a capsule; Aletris etc.

X. Sub. f. Luzuriagoideae:

Shrubs or undershrubs, often scandent; inflorescence terminal; ovary superior; fruit berry; Lapageria, Luzuriaga etc.

XI. Sub. f. Smilacoideae:

Climbing or scandent shrubs from a rhizome; leaves cauline, net-veined, flowers small dioecious in axillary umbels; ovary superior; fruit a berry: Smilax, Heterosmilax, Rhipogonum, etc. The large family contains many ornamental plants as well as those important medi­cinally or otherwise.

Garden ornamentals are species of Lilium, Tulipa, Gloriosa, Fritillaria, Agapanthus, Hayacinthus, Yucca, Dracaena, Cordyline, etc. Among those having medicinal value Aloe vera L., Veratrum album L., Asparagus racemosus Willd. Smilax sarsa-parila L., Smilax macrophyla Roxb., Convalaria majalis Linn, may be mentioned.

Phormium tenax Forst., Yucca filamentosa Linn, and a few others yield fibres from the leaves. The rhizome of Gloriosa and bulbs of Urginea and Scilla are poisonous. As food-plants Allium cepa L. the onion, A. satium L. the garlic and A. porrum Linn, the leek are well known. Fresh young shoots of Asparagus officinalis Linn, and A. adscendens Roxb. are taken as vegetables. Lapageria rosea Ruiz & Pav. of Chili yields edible berries.

The family Liliaceae as understood by the older taxonomists including Engler and Krause is a large family as described above. The great diversity of characters noticed in the different groups within the family indicates however that such a taxon cannot be a natural one.

Hutchinson therefore tried to give Liliaceae a more homoge­nous shape by removing 4 subfamilies, e.g. Allioideae, Dracaenoideae, Luzuriagoideae and Smilacoideae, 5 tribes, e.g. Petrosavieae, Dasypogoneae, Lomandreae, Calectae- sieae and Parideae and 2 subtribes, e.g. Odontostomineae and Ruscineae from this family.

This reduction in size however made rather slight alteration in the overall character of the family, only in the nature of the inflorescence which Hutchinson said might be of various types but never an umbel. Hutchinson changed the name of the order as Liliales wherein he included besides Liliaceae Tecophilaeaceae, Trilliaceae, Smilacaceae, Ruscaceae and Pontederiaceae.

According to Hutchinson most of the petaloid families of Monocots have been derived from Liliaceae. Such treatment of the family Liliaceae by Hutchinson has been supported by most modern workers like Anderson (1940), Maia (1941), Cheadle (1942) and Takhtajan (1969).

Cronquist while defining the family according to the older broad sense felt it necessary to merge Amaryllidaceae with Liliaceae although he maintains Agavaceae and Smilacaceae as distinct families.

The ancestral stock of Liliaceae or the order Liliales has according to Hutchinson affinities with Commelinales and Butomales, while Takhtajan and Cronquist consider that Liliales has been derived from Alismatales or the subclass Alismatideae.

The amended description of Liliaceae and of Tecophilaeaceae, Trilliaceae, Rusca­ceae and Smilacaceae are given below:

a. Liliaceae:

Herbs, mostly perennial or rarely soft wooded shrubs; roots from a rhizome, corm or bulb, sometimes tuberous; stem erect or climbing, leafy or scapose. Flowers bisexual or rarely unisexual, actinomorphic or slightly zygomorphic, in an inflorescence which is never an umbel.

Perianth mostly corolla-like, with or without a tube; segments or lobes 6, rarely 4 or more, mostly in 2 distinct but similar series, imbricate or the outer valvate.

Stamens usually 6 (rarely 3, or upto 12), hypo­gynous or adnate to and always opposite to the perianth-segments; filaments free or variously connate; anthers 2 locular, opening by slits lengthwise or rarely by apical pores.

Ovary superior or very rarely more or less adnate to the base of the perianth- tube and then semi-inferior, mostly 3-locular with axile placentas or rarely l-locular with parietal placentas; style entire or divided, rarely styles free.

Ovules usually numerous and mostly 2-seriate in each locule, rarely solitary. Fruit a loculieidal or septicidal capsule or a fleshy berry. Seeds with copious endosperm and straight or curved embryo.

b. Tecophilaeaceae:

Herbs with fibrous tunicated corms or thick flattened orbicular tubers. Leaves radical or towards the base of the flowering stem, linear or ovate- orbicular and cordate. Flowers bisexual, actinomorphic in simple racemes separately from the tuber or corm or paniculate, bracts large or small and membranous.

Perianth with or without a short tube, limbs 6, spreading or reflexed, subequal, imbricate. Sta­mens 6, perfect or 3 reduced to staminodes, inserted at the throat of the perianth; anthers 2-locular, often connivent, connective often produced at both ends, the base then swollen or spur-like, loculi opening by terminal pores, rarely by slits to the base and introrse.

Ovary more or less semi-inferior, 3-locular; style subulate or filiform. Ovules numerous, axile, 2-seriate in each loculus. Fruit a loculicidal capsule. Seeds numerous with a large embryo and fleshy endosperm. Hutchinson merges Cyanastraceae of Engler with Tecophilaeaceae while both Takhtajan and Cronquist treats Cyanastraceae as a distinct family.

c. Trilliaceae:

Small herbs with a simple erect stem from a short, thick or creeping rhizome. A few short leaf sheaths at base of stem and a pair of opposite leaves or a whorl of 3 or more leaves at the top of the stem; lamina distinctly nerved and reticulate between the nerves. Flowers one or more, terminal, sessile or pedicellate, variously coloured or sometimes greenish, bisexual, actinomorphic.

Perianth deciduous or per­sistent; segments free, sub equal or very different in two series; in the latter case the outer often broader and calyx-like, the inner petaloid, linear or filiform.

Stamens as many as the perianth segments, hypogynous or at the base of the segments and opposite to them; filaments filiform or slightly flattened, free; anthers 2-locular, basifixed, opening at the sides by slits lengthwise; connective sometimes produced at the apex.

Ovary superior sessile one locular with parietal placentas, or 3-locular or more locular with axile placentas. Style or style-branches 3-5; ovules numerous. Fruit a berry or a fleshy capsule at length loculicidally dehiscent. Seeds with hard or fleshy endosperm and a small embryo.

d. Ruscaceae:

Stem woody, erect or climbing. Leaves reduced to small scarious scales bearing in their axils the cladodes which are sometimes acute and spinescent at apex and bear on either surfaces or on their margins the small flowers in fascicles, or the flowers are in short terminal racemes. The flowers are bisexual or dioecious. Peri­anth segments 6, free or partly connate, in the latter case with a fleshy corona inside.

Stamens 6 or 3, the filaments connate into a column; anthers sessile extrorse, in the female flowers represented by an anther-less tube. Rudimentary ovary sometimes present in male flowers.

Ovary 3- or 1-locular; ovules 2 in each loculus, collateral, orthotropous or hemianatropous. Fruit a globose berry. Seeds solitary and globose, or two and flat on one side; embryo cylindrical, 2-4 times shorter than the endosperm. Takhtajan transfers Asparagus to this family which he names as Asparagaceae.

e. Smilacaceae:

Shrubs, climbing or straggling, often with tendril-like petioles and prickly stem and branches; rhizome often stout. Leaves alternate or opposite mostly leathery, 3-nerved, reticulately veined between the nerves. Flowers dioecious or rarely bisexual, small, arranged in axillary umbels, racemes or spikes. Perianth segments 6, equal or subequal free or rarely united into a dentate tube.

Stamens 6, rarely more or fewer, filaments free or united into a column; anthers apparently 1-locular, by the con­fluence of the cells, introrse. No rudimentary ovary in male flowers. Ovary superior, sessile, 3-locular; ovules 1-2 in each loculus, pendulous, orthotropous or half-anatropous, staminodes present in female flowers. Fruit a berry with 1-3 seeds,; embryo small in hard endosperm.

f. Pontederiaceae:

This is included in Liliales by Hutchinson as well as by Takh­tajan and Cronquist. Description of this family has been given with other families of Farinosae in which order it was placed by Engler.

Family # 3. Amaryllidaceae:

Amaryllidaceae are generally herbs from perennial bulbs, rarely shrubby or arboresoent from a rhizomatous root stock. Leaves are radical or distichous or spirally scattered on the aerial stem or in dense whorls forming a rosette; linear or lanceolate, thick, fleshy or stiff or grass-like and plicate.

Flowers on a distinct leafless scape, solitary or forming an um­bellate monochasial cyme enclosed by a pair of united spathelike bracts or many bracts; the inflorescence is often recemose, spicate or paniculate, of great size.

Flowers herma­phrodite, regular or medianly zygomorphic, usually epigynous. Perianth in 2 whorls of 3 segments in each; segments all similar united to form a tube, rarely free; lobes imbricate or valvate; a corona often develops at the throat of the corolla-tube.

Stamens 6 in 2 whorls, epipetalous; filaments often have stipule-like outgrowths on each side near base or the filaments have a basal cup, funnel-shaped or tubular; anthers introrse, dehiscing longitudinally or by terminal slits.

Ovary inferior or rarely semi-inferior, trilocular or 1-locular with many ovules in each cell in 2 series on axile placentas or ovules. few. Fruit a loculicidal capsule, sometimes splitting irregularly, or a berry. Seeds compressed or not with a small straight embryo in copious fleshy endosperm.

The above description of the family Amaryllidaceae is sensu lato as understood by Engler and other botanists. According to them the family consists of about 1000 species under 86 genera distributed mostly in the tropical and sub-tropical regions of the world with a few in the temperate countries, usually in dry situations.

The family exhibits great variations in vegetative as well as floral characters. Plants are bulbous or rhizomatous; the latter group may be acaulescent or with short aerial stem or may be woody and branched. Leaves crowded, radical or at the end of the stem and branches or scattered along the stem; thick and fleshy or leathery or papery and often plicate.

The inflorescence is an umbellate monochasial cyme on a distinct leafless scape or it may be a raceme terminating a leafy stem or a huge panicle as in Agave. The flower often develops a petaloid corona or para-corolla while in some cases petaloid stipule like outgrowths are formed and these often cohere in the shape of a staminal cup.

Stamens are 6 in the flowers of most genera but in some species the number may be 12 or more. The ovary is trilocular but in Leontochir and Calostemma it is unilocular. It is always inferior but in Tribonanthes it is superior. Fruit is usually a berry but capsule with leathery or woody pericarp also occurs.

The flowers are pollinated by insects which are attracted by the bright colour, the fragrance or by the nectar. Self-pollination also occurs where cross pollination fails. Flowers are often replaced by viviparous bulbils e.g. Agave, Fourcroya.

The usual floral formula is:

Many plants of this family have showy flowers and are cultivated as ornamentals. All species of Narcissus (including N. pseudonarcissus Linn.—the Daffodil) Haemanthus coccineus Liiui., Crinurn latifolium Thunb., Zephyranthes rosea (Spr.) LLndl., Hymenocallis andreana Nichols., Pancratium triflorum Roxb., Leucojam, Amaryllis, etc. belong to the subfamily Amaryllidoideae.

These have underground bulbs and flowers on leafless scapes. Many species of Alstromeria have beautiful red or yellow flowers and are cultivated. Agave sisalana Pers. the Sisal hemp and other species of Agave as well as different species of Fourcroja are cultivated in tropical countries for fibre obtained from the long thick leaves.

The peduncle of the huge panicle yields a copious quantity of sugary solution from which an alcoholic drink is prepared. Curciiligo orchi- oides Gaertn—the Talmuli or Mushali of the Indian Kavirajes is a small herb having medicinal properties. Polyanlhes tuberosa Linn, the Tube-rose or Rajani gandha has white fragrant flowers and are cultivated in Indian gardens.

The family is subdivided into 4 subfamilies, e.g.:

1. Amaryllidoideae:

Herbs with underground bulbs; flowers on leafless scape, solitary or in false umbel with an involucre of two or more spathe-like bracts; Amaryllis, Crinurn, Narcissus, Pancratium, Hippeastrum, etc.

2. Agavoideae:

Rhizomatous plants, acaulescent or arborescent, with thick fleshy leaves in dense whorls and terminal racemose inflorescence often paniculate; Agave, Fourcroya, Doryanthes, etc. Some of these live to a great age and are known as “Century plants”.

3. Alstroemerioideae:

Rhizomatous plants with long leafy aerial stem ending in an inflorescence; Alstroemeria, Bomarea, etc.

4. Hypoxidoideae:

Rhizomatous herbs with plicate leaves and spicate or race­mose terminal inflorescence; Hypoxis, Curculigo, Monileria. Most authors place Amaryllidaceae very close to Liliaceae and recently Cronquist merges Amaryllidaceae with Liliaceae. Rendle extends the scope of Amaryllidaceae by merging Velloziaceae with the same. This treatment of Rendle does not meet with the approval of others.

Hutchinson redefines the family Amaryllidaceae wherein he includes only the subfamily Amaryllidoideae of Engler’s family and transfers to this family 3 tribes Allieae, Agapantheae aAd Gilliesieae which were included in Liliaceae as described by the Englerian school.

He raises the subfamilies Agavoideae, Alstroe merioideae and Hypoxioideae to the rank of distinct families. Takhtajan supports Hutchinson in such treatments but keeps the tribe Allieae distinct from both and places the same in a family of its own, viz. Alliaceae.

Hutchinson who puts more im­portance on the nature of inflorescence describes Amaryllidaceae as noted below:—

Herbacious plants with perennial underground bulb or rhizome, leaves radical, linear, terete or flat, sessile or petioled, sheathing at the base; inflorescence on a scape, cymose, umbelliform or globose and compact, rarely flowers solitary; flowers regular, rarely zygomorphic, usually very showy; perianth petaloid, in 2 whorls of 3 similar segments each; stamens 6 in 2 whorls, opposite to perianth segments, anthers introrse, versatile, often some are staminodes, a conspicuous corona is usually present between the perianth and the androecium; ovary inferior, rarely half-inferior, 3-locular or 1-locular, ovules co, anatropous on axile placentation; fruit a loculicidal capsule or berry, seed with fleshy endosperm and straight embryo.

The descriptions of the other 3 newly created families of Hutchinson are given below:

a. Agavaceae:

Rootstock a rhizome, stem short or well-developed. Leaves usually crowded at the base of the stem or near the apex, linear, often thick or fleshy, entire or with prickly teeth on the margin. Flowers hermaphrodite, polygamous or dioecious, actinomorphic or slightly zygomorphic, racemose or paniculate, sometimes in a large thyrsus, the branches subtended by bracts.

Perianth-tube short or rather long, lobes or segments unequal to sub-equal; stamens 6, inserted at the base of the lobes or tube, filaments filiform or thickened towards the base, free; anthers introrse, linear, usually dorsifixed, 2-celled, opening lengthwise by slits, ovary superior or inferior, 3-celled with axile placentation, style slender, ovules numerous to solitary in each cell, superposed in 2 series, anatropous.

Fruit a localicidal capsule or berry. Seeds numerous or solitary, compressed, with fleshy endosperm surrounding the small embryo. The following genera are included in this family by Hutchinson, e.g. Agave, Fourcroya, Sansevieria, Dracaena, Cordyline, Phormivum, Tucca and Polyanthes.

b. Alstroemeriaceae:

Rootstock a rhizome with fibrous roots, sometimes bearing tubers; stem erect, ascending or climbing, leafy. Leaves alternate crowded or scattered, entire, the petiole usually twisted and reversing the surfaces. Flowers in a terminal cluster or irregular raceme, rarely solitary, showy, bisexual, more or less actinomorphic but often one segment of the perianth different from the others.

Perianth segments free to the base, inserted on an epigynous annulus, in two series often narrowed to the base, or spathulate. Stamens 6, inserted on an annulus at the base of the segments; filaments free, anthers introrse, oblong or ovoid, basifixed, opening lengthwise. Ovary inferior, 3-locular with axile placentation or one locular with parietal placentas; style filiform shortly 3-lobed.

Ovules numerous in each loculus or on each placenta, anatro­pous. Fruit a capsule, more or less truncate, locucidally 3-valved, crowned by the persisting epigynous annulus or by the persistent perianth-segments.

Seeds numerous with a small embryo in copious endosperm. About 100 species under 3 genera are restricted to Central and S. America. Different species of Alstroemeria are cultivated in tropical countries for the showy flowers.

Family # 4. Iridaceae:

Iridaceae are the plants that generally herbs with an underground corm or rhizome, rarely bulbous; rarely plants are under-shrubs. Leaves are equitant and sheathing at the base, radical or cauline, mostly narrow and ensiform; the cauline leaves are usually distichous.

Inflo­rescence terminal, cymose or racemose or paniculate, or flowers solitary; sometimes a few axillary flowers develop subsequent to the terminal flower; each flower is subtended by a spathe and a two-keeled bracteole is often present.

Flowers hermaphrodite, regular or medianly zygomorphic. Perianth petaloid, of 2 whorls of 3 members in each, united in a tube, sometimes the 2 whorls differ in structure. Stamens 3, representing the outer whorl of the androecium; filaments free or partially connate, inserted on the outer perianth segments; anthers extrorse.

Ovary inferior, trilocular with axile placentation or unilocular with parietal placentation; ovules many in each cell; styles 3 or style- branches 3, often petaloid, simple or bifid. Fruit a loculicidal capsule; seed with a small embryo enclosed in hard or fleshy endosperm.

The characters of the family is more or less quite distinct. The flowers vary only in some unimportant characters except that in the tribe Ixieae they are often medianly zygomorphic while usually they are regular. Leaves are equitant and in 2 rows in most of the genera while in Crocus and a few others they are linear or filiform and in several rows.

The floral formula is:

Three genera are shrubby with much branched stem. The secondary growth is due to the formation of a meristematic ring in the pericycle pro­ducing new vascular bundles and an outer secondary cortex. The family with over 1000 species in about 60 genera is widely distributed in temperate and tropical parts of the world.

In India a few Iris grow in the Himalayas and Assam and Crocus sativus Linn, is culti­vated in Kashmir, the broad flat stigmas of which yields the saffron of commerce. Species of Gladiolus are cultivated in the hills for the beautiful flowers. Belam- canda chinensis (L.) Leman—Dosh-bi-chandi (Beng.) and Cipura paludosa Aubl are cultivated in the plains.

The family is subdivided into 3 tribes by Diels as noted below:

1. Sisyrhinchieae:

Spathes terminal or lateral, stalked, rarely sessile; flowers solitary or more often several, developed centrifugally round a central one, mostly petioled; style-branches alternating with stamens; Crocus, Sisyrhinchiun, Romulea, etc.

2. Ixieae:

Spathes lateral, sessile, 1-flowered; fls. often zygomorphic; Ixia, Gladiolus, Freesia, etc.

3. Irideae:

Flowers numerous in terminal or lateral spathes, usually regular; style-branches opposite the stamens: Iris, Maraea, Tigridia, etc. Iridacea is close to Liliaceae and Amaryllidaceae. It is included in the Liliflorae by Engler while Hutchinson places it in a monotypic order Iridales and traces its origin from Liliales.

Takhtajan also places it in Iridales wherein he includes the families Geosiridaceae, Burmanniaceae and Corsicaceae. He includes Iridales in subclass Liliidae. Cronquist does not differ from Takhtajan in this respect. The family is considered advanced over Liliaceae and Amaryllidaceae having only one whorl of stamens.