1. Casuarinaceae:
Plants—evergreen much-branched drooping trees or shrubs with jointed whorled branches, monoecious or dioecious; internodes with striate grooves like that of Equisetum. Leaves—minute, scale-like in whorl of 4-16, usually linear to lanceolate, basaly united forming a sheath round the twig, exstipulate.
Flowers—unisexual, naked; male flowers verticillate in terminal spikes (catkin-like) and female flowers in ovoid or globose heads, subtended by bracts. Perianth—1 or 2, concave in male flowers but absent in female flowers. Stamens—in male flowers 1, subtended by 4 scale-like bracteoles.
Carpels—in female flowers 2, subtended by 1 bract and a pair of bracteoles; ovary superior, 2-celled but afterwards 1-celled bearing 2 ascending orthotropous ovules on a single parietal placenta; style 1, very short; stigma 2, long. Fruit—1-seeded winged nut, enclosed by 2 bracteoles and a bract; many such fruits are aggregated into a dry, woody, cone-like, multiple fruit.
This family contains a single genus Casuarina with about 40 species. It is a native of Australia.
Common plant of casuarinaceae include:
Beef-wood tree (Casuarina equisetifolia Forst.), a tall tree planted usually in avenues.
Casuarinaceae resembles strikingly to the Betulaceae in the structure and development of the pistil and ovary. The characteristic stem and leaf of the genus Casuarina are highly adaptive but it is very difficult to ascertain any trace of affinity with the Fagales.
The habit of Casuarina recalls the habit of Ephedra, a gymnosperm, thereby suggesting the derivation of gymnosperms from Casuarina-like primitive plant. This view has been propounded by Wettstein.
This family is readily distinguished from others by its equisetum-like jointed branches, whorled, minute leaves, and its woody cone-like fruit. Engler considers that the apparently simple anemophilous flowers, the approach to a catkin-like staminate inflorescence and the large rays in the wood of the family as a most primitive of dicotyledons.
Economically the family is important as a timber tree. Several species are cultivated extensively in our garden as ornamentals and also planted on the shores of India for afforestation.
2. Piperaceae:
Plants—erect or scandent herbs, or shrubs, with swollen nodes and more than one ring of scattered vascular bundles as in monocotyledons. Leaves—usually alternate, simple, often oblique, fleshy, exstipulate or with two adnate stipules. Inflorescence—spike (catkin). Flowers —minute, bisexual, sometimes unisexual (e.g., piper), nakel, hypogynous, bracteate. Perianth-absent. Stamens-10-10; filaments usually distinct.
Carpels—(2-5); ovary superior, 1-celled, with 1 basal orthotropous ovule; style 0-1; stigmas 1-5 (often brush-like as in Peperomia). Fruit—small drupe. Seed with endosperm and perisperm and minute embryo.
This family consists of about 10-12 genera and about 1,300 species, which are widely distributed in the tropics of both hemispheres.
Common plants of piperaceae include:
(1) Betle leaf plant (Piper betle L.), a stout climber, cultivated largely for its leaves, which are used as a masticatory.
(2) P. chaba Hunter, another stout climber, the wood of which is used as a pungent condiment.
(3) Long pepper (P. longum L.), a slender creeper.
(4) Black pepper (P. nigrum L.), another slender climber.
(5) White pepper (P. caninum L.).
(6) Peperomia reflexa Dietr., a common herbaceous tufted weed of waste places.
Engler and Rendle believed that the family belonged to the most primitive dicotyledons. But it is now generally held that the family has an indeterminate origin which may be an offshoot from ranalian ancestry. This family is readily distinguished by the presence of succulent habit, very minute naked flowers in spike inflorescence, and 1-celled ovary with solitary basal orthotropous ovule.
This family is of some economic importance. Fruit of Piper nigrum and P. caninum are used as spice. P. longum is used in medicine. Some species are ornamental, such as Macropiper, Piper, Peperomia, etc.
3. Salicaceae:
Plants—trees or shrubs, dioecious. Leaves—alternate, simple, vary from linear to cordate, stipulate. Inflorescence—catkin, erect or pendulous. Flowers—unisexual, sessile or shortly pedicellate, subtended by a hairy bract and a cup-like disc (an expanded floral axis), hypogynous.
Perianth—0. Stamens—in male flowers 2 or more; filaments slender, free, or more or less united at the base, transversely placed. Carpels — in female flowers (2-4); ovary sessile superior, 1-celled with numerous anatropous ovules arranged on 2-4 parietal placentae; style short or long, lateral or antero-posterior to the carpel; stigma 2-4-fid. Fruit —a small capsule dehiscing by two valves. Seed—very small with a thin testa, exalbuminous, comose; embryo straight.
This family consists of 2 genera and 300 species mostly confined to the temperate, alpine or artic zones.
Common plants of salicaceae include:
(1) Willow (Salix tetrasperma Roxb.) and
(2) Poplar (Populus alba L.) are the common plants which are found on the hills.
Engler considers this family to be primitive among the dicotyledons. This is partially supported by the presence of fossil remains straight from the tertiary age. Eichler, on the other hand, considers the members of the family arose as degenerated ones from complete, bisexual flowers. This family can be readily distinguished from the allied catkin-bearing families by dioecious plants, flowers subtended by hairy bracts and cup-like discs, and comose seeds.
This family is of little economic importance. Many species are ornamentals. The wood of Salix is used as a fuel and the twigs of Willows for basketry.
4. Moraceae:
Plants—trees or shrubs, rarely herbs (e.g., Dorstenia), monoecious or dioecious, evergreen or deciduous, usually with milky latex (absent in Cannabis and Humulus). Leaves—alternate, simple, entire, serrate or lobed, stipulate. Inflorescence—condensed spike or cymose, sometimes hypanthodium (e.g., Ficus). Flowers—small, regular, unisexual, hypogynous. Perianth—usually 4 in two whorls, sometimes 2 or 6, free or more or less united, valvate or imbricate.
Stamens—in male flowers generally equal in number and opposite the perianth-lobes, sometimes 2 or 1 (e.g., Ficus, Morus, Artocarpus, Dorstenia); filaments bent inwards in bud (e.g., Morus), but straight in Ficus; anthers mostly versatile.
Carpels—in female flowers (2); ovary superior, usually 1-celled with 1 pendulous ovule in each; stigma usually 2-fid. Fruit— drupe, syconus (e.g., Ficus) or sorosis (e.g., Artocarpus and Morus). Seeds—with fleshy endosperm or without curved.
This family consists of nearly 73 genera and over 1,000 species, which are widely distributed in the tropics.
Common plants of moraceae include:
(1) Banyan tree (Ficus benghalensis L.).
(2) Peepul tree (Ficus religiosa L.).
(3) Fig tree (Ficus cunia Ham., Ficus hispida L. f.).
(4) F. infectoria Roxb. = F. lacor Buch-Ham.
(5) Ivy fig (Ficus stipulata Wall)., a common herb found climbing on walls.
(6) India Rubber tree (F. elastica Roxb.).
(7) Jackfruit tree (Artocarpus integrifolia L. = A. heterophyllus Lamk.).
(8) Breadfruit tree (A. incisa L.f.), a native of Sunda islands, occasionally planted in gardens.
(9) Monkey jack (A. lakoocha Roxb), another fruit-tree.
(10) Mulberry—Morus australis Poir (Syn. Morus indica L.), chiefly cultivated for rearing silk-worms.
(11) Paper Mulberry (Broussonetia papyrifera Vent.), occasionally cultivated, the bark of which is chiefly used for manufacturing paper.
(12) Streblus asper Lour., a rigid shrub found on roadsides.
(13) Hemp. (Cannabis sativa L.), a tall erect annual herb.
(14) Hop (Humulus lupulus L.), a shrub cultivated in gardens.
This family is readily distinguished from other families of the order by the stinging hairs (when present) and milky latex, monocarpellary ovary with a single style, usually 2 stigmas, pendulous single ovule, and the cymose inflorescences on short axillary shoots. It can be distinguished from Euphorbiaceae by the simple ovary.
This family is economically important. Species of Ficus, Morus, Artocarpus yield edible fruits. A good quality of timber is obtained from Atrocarpus integrifolia. Cannabis yields fibers for cordage and a narcotic product known as hemp. Ficus elastica yields caoutchouc. The inner bark of Broussonetia is used for making paper.
The fruit of Hop is used in flavouring beer. Cow-tree (Brosimum galactodendron D. Don.), the latex of which is taken by the natives of Venezuela as a substitute for milk. Some plants are ornamentals, such as Ficus, Cecropia, Chlorophora, Cudrania, Dorstenia, etc. The leaves of Morus australis are used for feeding silk-worms.
5. Urticaceae:
Plants—usually herbs, rarely small trees (e.g., Holoptelea) or climbers, with watery latex, and sometimes with stinging hairs (e.g., Urtica, Fleurya) monoecious or dioecious. Leaves-alternate or opposite, simple, usually stipulate (exstipulate in Parietaria). Inflorescence —cymose, sometimes catkin-like (e.g., Boehmaria), on short axillary shoots. Flowers—small, green, regular, unisexual (bisexual in Parietaria), hypogynous.
Perianth—4 in two whorls, sometimes 5, free in male flowers but more or less united in female flowers, persistent. Stamens—in male flowers usually 4, sometimes 5, opposite the perianth-leaves; filaments bent inwards in bud, but when mature spring elastically backwards and outwards discharging cloud of pollen.
Carpel—in female flowers 1; ovary superior, sometimes inferior, 1-celled with 1 basal orthotropous ovule; style 1, ends in brush-like stigma. Fruit—an achene or drupe. Seeds—with oily endosperm and a straight embryo.
This family consists of about 42 genera and nearly 600 species which are chiefly tropical.
Common plants of urticaceae include:
(1) Nettle (Fleurya interrupta Gaud, and Urtica urens L., U. dioica L.), a common weed with stinging hairs.
(2) Rami grass (Boehmeria nivea Hook. & Arn.), commonly cultivated for its silky fibre.
(3) Gunpowder plant (Pilea microphylla Liebm.), so-called from the cloud of pollen discharged from the anthers when the plant is shaken; commonly found on damp walls.
(4) Pouzolzia indica Gaud., a common weed of waste places.
(5) Trema orientalis Bl., a very common shrub.
(6) Holoptelea integrifolia Planch, a large spreading tree.
This family is regarded to be most highly advanced in the order Urticales as evidenced by the abortion of the second carpel, basal position of the ovule and herbaceous habit. It is distinguished from other families of the order by the stinging hairs (when present), monocarpellary ovary with single basal orthotropous ovule, single style and cymose inflorescences on short axillary shoots.
This family is of little economic importance. Boehmeria furnishes fibre for Chinese ‘grass cloth’ known as Ramia. Species of Pilea, Pillionia, etc., are ornamentals.
6. Loranthaceae:
Plants—hemi-parasitic herbs with sympodial (but dichasial in Viscum) stems attached to the hosts by haustoria. Leaves—usually opposite, simple, entire, leathery, persistent, exstipulate. Inflorescence —solitary or dichasia in the axils of leaves. Flowers—almost regular, bisexual or unisexual and dioecious (e.g., Viscum), epigynous.
Perianth—generally of two similar 2-3-merous whorls, free or united into a tube which is often split down one side, sepaloid (e.g., Viscum) or petaloid (e.g., Loranthus); in the latter a slightly toothed or irregular rim (calyculus) is present below the perianth.
Stamens—isomerous and opposite to perianth leaves, epiphyllous. Carpel—(3-4); ovary inferior, probably 1-celled, with a large central placenta and undifferentiated ovules, of which usually only one attains maturity. Fruit —pseudocarp (ovary fused with the receptacular cup to form a berry or drupaceous fruit), pericarp membraneous or crustaceous. Seed —without testa, albuminous; embryo straight, large.
This family consists of 21 genera and over 500 species, mostly distributed in tropical and subtropical regions.
Common plants of loranthaceae include:
(1) Mistletoe (Viscum album L.) and
(2) Loranthus longiflorus Deser. = Dendrophthoe falcata E. Hing, and L. globossus Roxb. are commonly found on mango trees.
This family is related to Santalaceae in their habit, undifferentiated ovules and anomalous development of embryo-sac, but readily distinguished from it by the aerial parasitic habit, nature of the perianth, number of carpels, cup-shaped receptacle, absence of distinct ovules, and character of fruit. Economically this family is not important.
7. Santalaceae:
Plants—small trees or shrubs or herbs, semi-parasitic on roots. Leaves—usually opposite, simple, sometimes scale-like or 0, exstipulate. Inflorescence—various, usually cymose panicles in the axils of leaves and at the ends of the branches. Flowers—small, regular, bisexual or unisexual by reduction, epigynous or hypogynous, usually with nectar-secreting glands. Perianth—4-5, simple, sepaloid or petaloid, united below into a tube, valvate.
Stamens—4-5, opposite to the perianth leaves and are attached to the base or on the perianth- tube; tufts of hairs are present just behind each stamen. Carpels—(3-5); ovary inferior, sometimes superior (e.g., Santalum), 1-celled with central placenta bearing usually 3 ovules, each with 1 integument. Fruit—a drupe or an achene. Seed—without testa, albuminous; embryo straight.
The family consists of about 26 genera with 250 species widely distributed in the tropics.
Common plant of santalaceae include:
The Sandal wood tree (Santalum album L.), common in South India and often planted in gardens.
This family is closely allied to Loranthaceae but readily distinguished by the presence of central placenta, 3-5 carpellate ovary with 3 ovules, ovule with one or no integument, and the seed without testa. This family is less important economically. Santalum yields the ‘sandal wood’. Only Buckleya and Pyrularia are ornamentals.
8. Polygonaceae:
Plants—usually herbs with swollen nodes, sometimes climbing (e.g., Antigonon), seldom trees (e.g., Coccoloba uvifera). Leaves—alternate, simple, entire, usually with ochreate stipules (absent in Antigonon). Inflorescence—mixed in most cases, commonly a raceme or panicle of cymes.
Flowers—small, regular, usually bisexual (unisexual in Rumex), trimerous, cyclic or acyclic. Perianth—3-6, free, green, sometimes 5, petaloid, persistent. Stamens—6-9. Carpels—(3), rarely (2), united; ovary triangular, 1-celled with 1 basal orthotropous ovule; Style 1; stigma, 2-4. Fruit-triangular or biconvex nut. Seed with mealy endosperm. Embryo—curved.
This family consists of about 32 genera and about 800 species which are chiefly found in the north temperate zone.
Common plants of polygonaceae include:
(1) Knot-weed (Polygonum hydro-piper L.), a common weed of damp places.
(2) Polygonum orientale L. and P. barbatum L. are common weeds of ditches.
(3) Polygonum plebejum R. Br., a diffusely branched prostrate herb.
(4) Rumex maritimus L., a marshy weed.
(5) Dock (Rumex vesicarius L.) commonly cultivated for its acid leaves.
(6) Railway creeper (Antigonon leptopus Hook. & Arn. = Corculum leptopus Stuntz.), a common garden climber with small pink or white flowers.
(7) Muehlenbeckia platyclada Meisn.—Homalocladium, Platy-cladium (Muell.), Baily, are often planted in gardens for flattened leaf-like stems (phylloclades).
(8) Sea-grape (Coccoloba uvifera L.), a tree found in the Indian Botanic Garden, the leaves of which resemble Ficus benghalensis and likely to be mistaken for it.
(9) Rhubarb (Rheum emodi Wall.), a medicinal plant commonly found in the hills.
This family is closely allied to Chenopodiaceae, Amaranthaceae and Nyctaginaceae but readily distinguished by the ochreate stipules, triangular 1-celled ovary, with solitary basal ovule, 1-seeded fruit and curved embryo. It bears some affinity with Urticaceae in the orthotropous ovule and stipule.
This family is not much important economically. Fagopyrum (buckwheat) and Rheum (rhubarb) are useful as food in the western countries. Rumex vesicarius is used as a vegetable. Rheum emodi is used in medicine. Some plants are also recognized as ornamentals, such as, Antigonon, Coccoloba uvifera, Polygonum aubertii, etc.
9. Amaranthaceae:
Plants—mostly annual or perennial herbs, sometimes shrubs (e.g., Deeringia). Leaves—alternate or opposite, simple, generally entire, often more or less hairy, exstipulate. Inflorescence—simple or compound spike, or raceme, or dichasia. Flower small, regular, bisexual, sometimes unisexual (e.g., Amaranthus), hypogynous, with a pair of membraneous, persistent, bracteoles. Perianth—5, dry and membraneous, often white and shining or coloured, free or more or less united, persistent, imbricate.
Stamens—5, opposite the perianth segments; filaments often united into a membraneous tube which may bear simple, lobed or fringed, petaloid outgrowths between two stamens. Carpels—(2-3); ovary superior, 1-celled, frequently with solitary basal or campylotropous ovule; style 1-3. Fruit—a nutlet or utricle (e.g., Achyranthes) or pyxis (e.g., Celosia). Seed—black with bony shining testa, and mealy endosperm. Embryo—horseshoe-shaped or annular.
This family consists of 64 genera and about 800 species which are chiefly found in the tropical or subtropical regions.
Common plants of amaranthaceae include:
(1) Amaranthus spinosa L., a common spinous weed.
(2) Amaranthus viridis L. and A. gangeticus L. are cultivated as vegetables.
(3) Cocks’ comb (Celosia cristata L.), commonly planted in gardens.
(4) Celosia argentea L., a weed found in waste places.
(5) Achyranthes aspera L.= Aerva aspera Spreng., a common weed.
(6) Alternanthera sessilis R. Br., a very common weed found in moist places.
(7) A. paronychioides St. Hil., common in the vicinity of Railway lines near Calcutta.
(8) Aerua scandens Wall. = Aerva sanguinolenta Bl. and A. lanata Juss., common weeds.
(9) Globe Amaranth (Gomphrena globosa L.), commonly cultivated in gardens.
(10) Deeringia celosioides Br = D. amaranthoides Merr., a climbing shrub with purple berries.
(11) Pupalia atropurpurea Moq., a common weed with hooked fruits.
(12) Digera arvensis Forsk.= D. muricata Mart., a weed.
(13) Psilotrichum ferrugineum Moq., a weed of fields and waste places.
(14) Allmania nodiflora R. Br., a dichotomously branched annual.
(15) Cyathula prostrata Bl., a slender erect weed.
This family is closely allied to Chenopodiaceae but readily distinguished by the dense spicate inflorescence, scarious bracts and bracteoles, membraneous and shining perianth, and usually connate filaments.
This family is of little economic importance. Some plants are used in medicine, such as, Achyranthes, Aerua, Amaranthus, etc., and as pot-herbs. A few are ornamentals, such as, Celosia, Gomphrena, etc.
10. Chenopodiaceae:
Plants—usually annual or perennial succulent herbs, sometimes shrubs, very rarely trees (e.g., Haloxylon), monoecious or dioecious with swollen nodes. Leaves—usually alternate, rarely opposite (e.g., Salicornia), simple, fleshy, entire or variously lobed (but in halophytic species, such as Suaeda, Salsola, Salicornia, etc., are much reduced in size, linear or even scale-like), glabrous (but covered with mealy hairs in Chenopodium, Artiplex, Salsola), exstipulate.
Inflorescence—dense spike or panicle or cymose (at first dichasia but soon change into monochasia). Flowers—regular, bisexual (but unisexual in Spinacia and Artiplex), hypogynous (but epigynous in Beta), often with scarious bracts and bracteoles. Perianth—5, usually more or less dry and membranous, free or more or less united, persistent.
Stamens—5 (but 2 in Salicornia), opposite the perianth leaves; filaments united at the base into a short tube. Carpels—(2-3); ovary superior, sometimes inferior (e.g., Beta), 1-celled with a campylotropous erect or pendulous ovule; style short or long; stigma usually 2-3-fid. Fruit—lens- or kidney- shaped nutlet. Seeds—albuminous or exalbuminous with horny testa; embryo curved (e.g., Chenopodium, Artiplex, Salicornia, Beta, etc.) or coiled (e.g., Suaeda, Salsola, etc.).
This family consists of about 102 genera and 1,400 species which are cosmopolitan.
Common plants of chenopodiaceae include:
(1) Spinach (Spinacia oleracea L.) commonly cultivated.
(2) Lamb’s quarters (Chenopodium album L.) and C. ambrosoides L., tall herbs which are also cultivated.
(3) Suaeda maritima Dumort, commonly found in saline regions.
(4) Salt-bush (Artiplex hortensis L.).
(5) Salicornia brachiata Roxb. and
(6) Arthrocnemum indicum Moq., prostrate woody shrubs commonly found in the Sundribans.
(7) Sugar-beet (Beta vulgaris L.), commonly cultivated for obtaining sugar.
This family is allied to Amaranthaceae in the presence of monochlamydeous flowers, uniseriate stamens and a single basal ovule in 1-celled ovary. It is also allied to Phytolaccaceae in the plan of floral structure, and is supposed that the family has been derived from Phytolaccaceae. Chenopodiaceae is readily distinguished from allied families by the fleshy habit, absence of scarious bracts, 2-3-carpellate ovary which is 1-celled and 1-ovuled, and the nature of the embryo.
This family is not of much economic importance. Spinacia oleracea, the common spinach, is used as a vegetable. Some plants are considered to be fodder plants, such as, species of Artiplex, Kochia, etc. C. quinoa yields a sort of grain with mealy perisperm. The seeds of C. anthelminticum yield a kind of oil which is used as a vermifuge. Chenopodium bonus and Hemichroa are cultivated as pot-herbs.
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