Classification of Farinosae: 5 Families | Monocotyledonae

In this article we will discuss about the Classification of Farinosae. According to Engler and Prantl, Farinosae consists of five families:- Flagellariaceae 2. Commelinaceae 3. Eriocaulaceae 4. Pontederiaceae 5. Bromeliaceae.

Family # 1. Flagellariaceae:

Flagellariaceae are shrubs or undershrub’s, erect or climbing. Leaves are alternate, plicate or flat with several prominent nerves, with a long tubular sheath covering major part of the internode; leaf tip often prolonged into a tendril. Panicles terminal; bracts usually lanceo-­late.

Flowers regular, hermaphrodite or dioecious, usually small. Perianth in 2 series with 3 segments in each, persistent; segments free, imbricate, scarious or somewhat petaloid. Stamens 6, filaments filiform, free or slightly adnate to the base of perianth- segments; antliers 2-celled, basifixed, introrse, dehiscing longitudinally.

Ovary superior, 3-locular, with a solitary anatropous ovule on axile placentation, spreading or pendu­lous; style short with 3 stigmatic branches or styles 3 and distinct.

Fruit small, indehiscent, a berry or a drupe; seeds with copious mealy endosperm and a small embryo situated at the end or on one side of the endosperm the position of the embryo is in­dicated by a disc-like callosity on the surface -called as embryotega (or embryostega); embryo lenticular.

This is a small family with only 2 genera and 5 species found in the tropical Africa, India and eastward up to Australia. Flagellaria indica Linn, occurs in lower Bengal and different parts of S. India in damp situations. The other genus Hanguana (Syn. Susum) is found in Ceylon and Malaysia. The family is of no economic importance.

This family is included in the order Farinosae by Engler due to the mealy nature of endosperm. Hutchinson breaks up this order into 7 orders and places Fagellariaceae in Commelinales. Takhtajan as well as Cronquist considers that Fagellariaceae is closer to Restionaceae than to Commelinaceae and places Fagellariaceae under Restionales.

Airy Shaw considers that the 2 genera Flagellaria and Hanguana are so distinct that these are to be treated as belonging to two separate families.

He, therefore, establishes another monotypic family as Hanguanaceae in which he includes the genus Hanguana with erect robust herbs, which are stoloniferous with flowers dioecious, inner perianth segments larger, stigma sessile and broadly. 3-lobed. Takhtajan supports Airy Shaw in the splitting up of the older family to 2 smaller monotypic families e.g. Flagellariaceae and Hanguanaceae.

Family # 2. Commelinaceae:

Commelinaceae are annual or perennial herbs, erect or occasionally twining, with jointed more or less succulent stems and often with subterranean rhizome. Calcium oxalate crystals are present in the tissues. Leaves are alternate, sheathed at the base; sheaths closed membranous and often nervosa.

The inflorescence is of a cincinnus type or paniculate or cymose cluster, axillary or terminal, enclosed by spathe-like bracts or leaf-sheath which it sometimes perforates; rarely flowers solitary; floral bracts small, rarely foliacious and distichously imbricate. Flowers usually hermaphrodite, regular or often medianly zygomorphic, hypogynous, blue, white or pinkish.

Perianth in 2 series with 3 segments in each, segments free, imbricate, rarely united; the outer sepaloid and the inner petaloid, rarely one of the 3 petals is reduced to a scale-like structure.

Stamens 6 in 2 whorls, all fertile or only 3 or 2 are fertile and the rest reduced to staminodes or absent; filaments usually free, smooth or bearded with moniliform brightly coloured hairs; anthers basifixed, 2-locular; loculi parallel and usually contiguous, opening by longitudinal slits or by apical pores, connectives of various types.

Ovary supe­rior 3- or 2-locular; ovules few or solitary in each cell, orthotropous, on axile placentation; style terminal, simple with small capitate or 3-lobed stigma. Fruit a loculicidal capsule or rarely fleshy and indehiscent; seeds angular, in 2 series in each cell, mostly muricate, ridged or reticulate, with copious mealy endosperm, rarely arillate; embryo marginal or nearly so, its position indicated by an embryostega.

The flowers are pollinated by insects which are attracted by the coloured petals and filaments of the stamens; self-pollination has rarely been observed, while small cleistogamous flowers are produced on the subterranean branches of the rhizome of Commelina benghalensis Linn.

Floral formula:

The family contains about 600 species in 38 genera.

These are placed under 2 subfamilies as noted below:

Sub. f. Tradescantieae—Flowers actinomorphic; tribes 2-Hexandreae, Triandrae.

Sub. f. Commelineae—Flowers zygomorphic; tribes 2, Declinatae, Inclinatae.

The family is well represented in India by several species, common among them are Commelina benghalensis Linn., C. obliqua Buch. Ham., Murdannia nudiflorum (R. Br.) Bruckner (Syn. Aneilema nudiflorum R. Br.).

Aneilema liniolatum Kunth, Floscopa scandens Lour., Cyanotis cristata Schult. etc. Streptolirion cordifolium (Griff.) O. Ktz. is a climber of the temperate Himalayas. Zebrina pendula Schnitze. of Mexico, Rhoeo discolor Hence of Trop.

America and Setcreasea purpurea Boom of Mexico are cultivated in gardens as ornamental plants. The long hairs on the stamens of Rhoeo discolor show protoplasmic movements when observed under microscope. The family is included in the order Farinosae by Engler with other families having mealy endosperm in the seeds.

Hutchinson splits Farinosae into 7 smaller orders and Commelinaceae is placed by him in Commelinales along with Flagellariaceae, Mayacaceae and Cartonemataceae the last was formerly included under Commelinaceat but separated as a distinct family to accomodate Cartonema a xerophytic Australian genus.

Hutchinson derives the order Commelimales from the 2 most primitive orders, viz. Butomales and Alismatales, i.e. from Helobieae. Commelinaceae besides being closely related to Fagellariaceae, Mayacaceae and Cartonemataceae appears to be close to Pontederiaceae having mealy endosperm in the seeds which are longitudinally ridged.

Economic importance: Besides the ornamental garden plants mentioned above there are a few species which are used medicinally. Aneilema scapiflorum is used as a sub­stitute of Curculigo orckioides Gaert. the “Musali” or “Talmuli” of the Indian Kavirajes. The plant body of Commelina benghalensis Linn, and of several species of Aneilema and Murdannia are used in Leprosy and Leucoderma.

The bruised plant of Commelia nudiflora Linn, relieves pain in burns, boils, etc. The roots of Cyanotes are used to expel worms in cattle and alloying fevers. The juice of the stem of Floscopa is used in eye sore. The leaves of Commelina benghalensis Linn, are taken as pot herbs and these are laxative. The juice of the leaves of this species neutralises the poisoning effect from the touch of the hairs of caterpillars.

Family # 3. Eriocaulaceae (Eriocaulonaceae):

Eriocaulaceae are small herbs, usually perennial, with a very short axis and a tuft of densely arranged linear grass-like radical leaves.

Flowers very small crowded on a globose, monoecious or dioecious heads terminating a slender, simple, rarely branched scape, subtended by an involucre of bracts; the peduncle sheathed at the base much exceeding the leaves; the bracts of the involucre are usually prominent and the inner ones larger.

Flowers unisexual sessile or shortly stalked, regular or rarely zygomorphic in the axil of a scarious, saclike, coloured or colourless bract of its own; in monoecious heads the- staminate flowers are arranged in the centre and the pistillate on the periphery or flowers of both sexes are inter mixed.

Perianth or perigonyum in 2 distinct whorls, seg­ments scarious or membranous or rarely hyaline, 2-3 in each whorl, the outer segments free or united, the inner united, infundibuliform or cupular, rarely hairy at apex usually stalked, rarely inner whorl absent.

Stamens alternate to and as many as outer segments, often more, inserted on the inner whorl of united segments; anther 1-2-celled, introrse, dehiscing by vertical slits; filaments slender; pistillodium often present in ♂ flowers.

Ovary superior, 2-3-celled with a single orthotropus ovule in each, pendulous from the axile placentas; style 1, with 2-3 branches, each branch simple or forked; staminodes rarely present in 2 flowers. Fruit a loculicidal capsule, 2-3-seeded; seeds with copious mealy endosperm and minute lenticular embryo situated opposite to the hilum; the horny testa is smooth or striate or hairy.

Floral formula:

The flowers are entomophyllous. When fruits mature the heads fall as a whole or the individual flowers are detached and distributed by wind, the hairy inner and wing-like outer segments help in the distribution.

The family consists of about 1150 species in 13 genera of which Eriocaulon contains 370 species. Paepalanthus is another American genus having almost equal number of species.

The plants grow usually in damp situations in the warmer parts of the world. The family is represented in India by several species of Eriocaulon the most common among them are E. sieboldianum S. & Z., E. truncatum Buch.-Ham., E. trilobum Buch.- Ham., E: quinqueangulare Linn.

The family is subdivided into 2 subfamilies as noted below:

I. Eriocauloideae:

Inner perianth segments or petals glandular near apex on the, inner side; stamens twice the number of petals.

II. Paepalanthoideae:

Glands on petals absent, petals rarely absent; stamens double the number of petals or sepals. The family has been included in Farinosae by Engler on account of the mealy endosperm in the seeds.

Hutchinson considers it to be a much advanced family with small unisexual flowers crowded in dense heads, reduced and united perianth-lobes and other characters, and derives the order Eriocaulales with the single family from Commelinales. Takhtajan and Cronquist also include Eriocaulareae in the mono typic order Eriocaulales which both of them place after Commelinales.

The family is of little economic value. Eriocaulon setaceum Linn, and a few other species have medicinal value. The flower-heads if preserved before the flowers open remain as such for a long time and those of the genus Syngonanthus are thus preserved as ever-lasting flowers.

Family # 4. Pontederiaceae:

Pontederiaceae are aquatic herbs, floating or rooted to the mud; rhizome with a sympodial axis, the successive branches ending in an inflorescence; plants often stoloniferous; branches often adnate to the main shoot from which they spring; sometimes the branch with the inflorescence is pushed aside and appears to spring from a leaf-sheath due to formation of extra branches; air cavities present in all parts of the plant body; raphide-crystals are often present also.

Leaves are simple, alternate with spongy and often inflated petiole, sheathed at the base.

The inflorescence is a terminal spike or panicle which is actually a cymose pseudo-raceme, subtended by a spathe-like leaf sheath; bracts minute of absent. Flowers bisexual, usually regular or slightly zygomorphic, usually, showy. Perianth persistent, petaloid, with 6 lobes in 2 series, connate below; lobes imbricate.

Stamens 6 in 2 whorls of 3, or only 3 or rarely only 1, inserted on the perianth at different heights; filaments free, filiform, somewhat unequal in size or one much more larger than the rest; anthers 2-locular, dehiscing longitudinally or rarely by apical pores.

Ovary superior, 3-locular, with many anatropous ovules on axile placen-­tation or ovary I-locular with ovules on parietal placentation, rarely ovule solitary and pendulous in an 1-locular ovary; style long and with entire or lobed stigma. Fruit a capsule opening by 3 valves or an one seeded nut; seeds longitudinally ribbed, with copious mealy endosperm and a straight cylindrical centrally placed embryo.

The showy flowers attract lots of insects and the flowers are usually entomophilous but cleistogamous flowers occur in some species of Hydrothrix and Heteranthera. In such flowers the number of stamens is reduced to one.

In Heteranthera there is a central stelar cylinder and the vascular bundles are colateral. The root is polyarch in all genera. The leaf anatomy shows a reverse orien­tation of the pallisade cells and the xylem towards the lower surface of the leaf.

This is a small family with about 30 species under 7 genera occurring in the marshes and fresh water pools of the tropical and subtropical countries of the world. Monochoria hastata Solms-Laub. and M. vaginalis Presl with blue flowers are common in the marshes all over India in the plains.

Another exotic weed a floaing herb with beautiful pale purple flowers has become an obnoxious pest of lakes and streamlets all over India and is an introduction from tropical America, viz. Eichhomia crassipes (Mart.) Solms- Laub. The plants are of no economic importance.

Pontederiaccae was placed in the order Farinosae by Engler due to the presence of mealy endosperm in the seeds. Hutchinson places this family in his Liliales due to more or less similar and petaloid perianth segments in two whorls. Both Takhtajan and Cronquist support Hutchinson and included Pontederiaceae in Liliales where the families have binucleate pollens.

Family # 5. Bromeliaceae:

Bromeliaceae are plants of this family are mostly epiphytic herbs, sometimes terrestrials, with very short stem; rarely elongated and branched, e.g. Puya which are erect and shrubby, Tillandsia hanging like lichens from forest-trees or Pitcairnia with climbing habit. Some terrestrials are stoloniferous and the plants propagate vegetatively, e.g. Cryptanthus, Ananas, etc.

The primary root perishes early and adventitious roots develop from the nodes often piercing the leaf sheath; these roots are of 2 kinds, the absorbing roots and fixing roots.

Leaves are sessile, sheathed at the base, linear, channeled above, densely crow­ded to form a rosette on the shortened stem and with the stem-clasping sheaths repre­sent a cup where water collects; the inside of the leaf-bases arc furnished with a kind of peltate hairs which absorb water with the dissolved particles that fall there and help in the nutrition of the plant; the leaves are often fleshy or chartaceous with strongly cuticularised surface and water-storing parenchyma in the mesophyl; peculiar water-absorbing scales and hairs all over the leaves and on the whole plant body are present especially in the epiphytes that absorb atmospheric moisture while scaly hairs covering the leaf surface, reduce the rate of transpiration; the leaf-margin may be entire or spinose, the spines short or long and hook-like helping the plant to climb by fixing the hooks to the support; the leaves are often coloured.

The inflorescence is a terminal spike or panicle with bracts and bracteoles; bracts are usually brilliantly coloured and often form an involucre or a rosette; the flowering axis is often short with flowers densely crowded, or elongated with basal sterile bracts; in some cases the flowering shoot persists for several years and produces inflorescence in each successive season; rarely flowers solitary.

Flowers hermaphrodite or rarely unisexual by abortion, regular or very rarely slightly zygomorphic where the inflorescence is more or less one-sided or pendulous; perianth persistent, in 2 whorls of 3 segments each, the outer sepaline and the inner petaline; the sepals and petals are more or less united or free and with convolute aesti­vation; a pair of scales or nectaries usually present at the base of each petal on the inner side.

Stamens 6, in 2 whorls, inserted in the perianth segments or adnate to them at the base, free from each other or connate below; the anthers bilocular, usually, versatile, dehiscing introrsely by longitudinal slits; the pollens show characteristic markings; they are grooved or pitted or reticulate, rarely smooth.

Ovary superior to inferior, 3-locular, usually with numerous ovules in each locule on axile placentation which often bifurcates; ovules anatropous; style long and slender with 3 stigmas which often remain spirally twisted at first, nectar-secreting septal glands are often present on the ovary-wall.

The fruit is usually a many-seeded capsule, dehiscing septicidally, or in case of inferior ovary the fruit is a berry with few seeds; the fruit is often more or less enclosed by the persistent perianth; in Ananas the whole inflorescence form a succu­lent syncarp. Seeds small, often provided with a wing or plumose pappus-like appen­dage; endosperm copious, mealy; embryo small, in a hollow space near the hilum.

The flowers are pollinated by insects which visit the flowers in search of nectar and also being attracted by the bright colour of petals and bracts.

The family consists of about 1900 species under 59 genera and almost wholly confined to the New World while Pitcairnea feliciana (A. Chev.) H. & M. occurs wild in W. Africa and Ananas comosus (L.) Merr. is cultivated in all tropical countries.

Harms subdivided the family as follows:

Sub. f. I Navioideae:

Ovary superior, ovules few; fruit a capsule seeds without wing or appendage; 1 genus—Navia.

Sub. f. II Pitcairnioideae:

Ovary superior or half inferior, ovules many; fruit a capsule, seeds with a wing or appendage; mostly terrestrials;—12 genera, Puya, Pitcairnia, Dyckia, etc.

Sub. f. III Tillandsioideae:

Ovary superior, rarely half inferior, ovules many; fruit a capsule, seeds with pappus-like appendage; terrestrials or epiphytes;—12 genera, Vriesia, Tillandsia (250 spp.), etc.

Sub. f. IV Bromelioideae:

Overy inferior, ovules usually many; fruit a berry, seeds without wing or appendage; terrestrials; genera 34, Ananas, Bromelia, etc. The genus Navia is now considered to be an extreme form of the Sub. f. Pitcair­nioideae and does not form a distinct subfamily.

Engler placed Bromeliaceae in his Farinosae because of mealy endosperm in the seeds. Rendle followed Engler’s treatment. Hutchinson who splitted the order Farinosae into 7 orders placed Bromeliaceae in a distinct monotypic order Bromeliales which he derives from Commelinales. According to him Bromeliaceae is related to Commelinaceae but is more advanced.

Both Takhtajan and Cronquist place Bromeliaceae in a monotypic order Bromeliales but while Takhtajan puts Bromeliales and Commelinales very close to each other, Cronquist in his system of classification places them far apart in the same subclass Commelinidae considering Bromeliaceae to be a much advanced family over Commelinaceac. Smith Considers that Bromeliaceae is more allied to Rapataceae both having similar type of perianth and embryo.

According to him these 2 families arose from a common stock.

Economic Importance:

The Pine-apple—Ananascomosus (L.) Merr. is famous for the delicious fruit which is a syncarp formed from the whole inflorescence including the axis, bracts and floral parts. The species also yields a fine fibre from the leaves used for the manufacture of Pina cloth. The plant is widely cultivated in all tropical countries.

Neoglaziovia variegata Mez., Bromelia serra Griseb. and B. magdalenae C. H. Weight also yield fibre. The dry plants of Tillandsia usneoides Linn, are used for stuffing pillows and cushions. Many plants are cultivated as garden ornamentals for their brightly coloured leaves, bracts and flowers, e.g. different species of Billbergia, Aechmea, Vriesia, Nidularium, Puya,’ Pitcairnia, Tillandsia, etc..