PLANT-BIO: SYSTEMATIC BOTANY

RUBIACEAE
DISTRIBUTION IN THE WORLD:
This family is commonly called as the madder family. There are nearly 630 genera and 10,400 species.
They are Cosmopolitan in distribution but especially in the tropical and warm regions, especially the woody members.

MAP SHOWING THE WORLDWIDE DISTRIBUTION OF RUBIACEAE MEMBERS

DISTRIBUTION IN INDIA:
There are nearly 113 genera, 616 species and nearly 9 subspecies and 67 sub varieties are distributed in India.

DISTRIBUTION IN TAMILNADU:
There are nearly 61 genera and 243 species are distributed throughout India.
Some of them are listed below;

Canthium (10 spp.)
Cinchona (4 spp.)
Coffea (2 sp.)
Deccania (2 sp.)
Acranthera
Canthium
Cinchona
Coffea
Deccania
Dentella
Rubia

MAJOR GENERA:

Psychotria (1500 spp.)
Galium (400 spp.)
Ixora (400 spp.)
Pavetta (400 spp.)
Hedyotis (400 spp.)
Tarenna (370 spp.)
Randia (250 spp.)
Gardenia (250 spp.)
Palicourea(250 spp.)
Mussaenda (200 spp.)
Borreria (150 spp.)
Rondeletia (125 spp.)

KEY CHARACTERS OF THE FAMILY:
1. Leaves opposite, rarely ternate.
2. Stipules interpetiolar.
3. Flowers bisexual, actinomorphic.
4. Calyx adnate to the ovary.
5. Flower epigynous often tubular.
6. Stamens alternate to the corolla lobes.
7. Ovary inferior two or more locular

SALIENT FEATURES OF THE FAMILY:
HABIT:
Mostly trees (Adina, Neolamarckia) or Shrubs (Ixora, Gardenia), Lianas, herbs (Galium), or rarely aquatic (Limnosipanea sp.), epiphytic (Myrmecodia) with large swellings on roots inhabiting ants, usually with iridoids, raphide crystals common.

Anthocephalus cadamba

Sometimes some of the members of rubiaceae are ant – inhabited as in Nauclea.

Nauclea Sp.

LEAVES:
Leaves opposite, or whorled usually entire with pinnate venation.

Whorled arrangement of leaves

STIPULES:
Stipules present, Interpetiolar & usually connate occasionally leaf like.

Interpetiolar stipules

INFLORESCENCE:
Inflorescence determinate occasionally reduced to a single flower, terminal or auxillary.

FLOWERS:
Flowers usually bisexual, radial, often heterostylous, frequently aggregated.

SEPALS:
Sepals usually 4 or 5, connate, sometimes with colleters on adaxial surface.

PETALS:
Petals usually 4 or 5, connate, forming a wheel shape to funnel shaped corolla. The lobes are valvate, imbricate or contorted.

STAMEN:
Stamens usually 4 or 5, filaments usually adnate, to corolla & positioned within corolla tube or at its mouth. Anther 2- locular, Opening by longitudinal slits.

POLLEN:
POLLEN grains usually Tricolporate.

GYNOECIUM:
Ovary inferior, with axile placentation; stigma 1 or 3, linear, capitate, or lobed. Ovules 1 to numerous in each locule.

OVULES:
Ovules 1 to numerous in each locule. Anatropous to hemitropous unitegmic ovules often, with a funicular obturator.

NECTARS:
Nectors are often present as a nectiferous disk at the top of the ovary.

FRUITS:
Fruit a loculicidal to septicidal capsule, berry, drupe, schizocarp or indehiscent pod.

SEEDS:
Seeds with usually straight embryo embedded. Oily endosperm sometimes
with reserves of starch & hemicellulose.

Figure showing the salient features of Rubiaceae

PHYLOGENIC RELATIONSHIP:

Euasteroides families have flowers with epipetalous stamens. Molecular analysis has provided strong support for this clade. It indicates the presence of two subclass
EUASTERID I (lamiids)
EUASTERID II (campanulids)

EUASTERID I:
This clade received only weak support with 3 or 4 gene analysis. Within this Garryales, Icacinaceae, mettiniusaceae, ancothecaceae are sisters to the rest of the clade. The remainder of euasterid I is strongly supported as monophyletic in analysis of both 3 and 4 genes. It consists of several sub clades – Gentianales, Solanales, Lamiales, as well as Vahlia (Vahliaceae) and Boraginaceae. Gentiales constitute a well supported clade of 5 families. The gentiales clade consists of 1000 genera and 14000 species. Morphological and anatomical synapomorphies includes vestured pit, interpetiolar stipules, corolla convulate in bud, intraxylary phloem.

RUBIACEAE:
Rubiaceae are sister to the remainder of the clade in most molecular phylogenetic analysis. Phylogenetic relationships with rubiaceae have been analysed using morphology and combined morphology & DNA datasets. Following rubiaceae, a clade of the remaining families received moderate to strong support in analysis based on 3 or 4 genes. This clade of four families also shares a feature of wood anatomy.

ENDEMICS OF PENINSULAR INDIA:
Acranthera (2 sp.)
Hedyotis (18 spp.)
Ixora (10 spp.)
Lasianthus (16 spp.)
Hedyotis (9 spp.)
Ophiorrhiza (22 spp.)
Psychotria (11 spp.)
Plectronia (4 spp.)
Neanotis (7 spp.)
Borreria (3 spp.)
Knoxia (3 spp.)
Pavetta (4 spp.)
Wendlandia (2 spp.)

DISCOVERY OF NEW SPECIES:
Genus HEDYOTIS L. comprising about 515 species. 77 species are reported in India. 33 species are reported in TAMILNADU. New species Hedyotis nairii M.Murugesan & V.Balasubramaniam, reported from Velliangiri hills. The Features of this new species are as follows:

They are elliptic-lanceolate or oblanceolate leaves, glandular stipules, glabrous cyme, & pedicellate flowers.

ECONOMIC IMPORTANCE:

MEDICINAL USES:

CINCHONA : Quinine, a drug obtained is used in treating malaria.
PSYCHOTRIA : Ipepac, a drug used to induce vomitting.
GALIUM : In the form of infusion as diuretic, anticorbustic.

GALIUM SP.

CINCHONA SP.

GEOPHILA : Given for diarrhoea in malaya.
CERISCOIDES : Resin exudated from this plant is given for enlarged spleen.
CANTHIUM : Fruits constitute a ayurvedic drug “karee” effective against indigestion
Gardenia jasminoides : The root is used in dyspepsia & nervousdisorders.
ANTHOCEPHALUS : Given as antidote for snake bite

Gardenia jasminoides