Distribution of Apocynaceae:
It is commonly known as Oleander family. It comprises 180 genera and 1500 species out of which 84 species or 30 genera are present in India. The members are most abundant in tropics and sub-tropics.
Economic Importance of Apocynaceae:
- Vegetables: The pulpy fruits of Carissa carandus (H. Karaunda) are edible and also pickled.
- Medicinal: The root of Rauwolfia serpentina (H. Sarpgandha) are used in lowering blood pressure, sedative, stimulator for uterine contraction and in mental diseases. The juice of leaves is used for removal of opacities of the cornea of the eyes. Anti-cancerous drugs are extracted from Catharanthus roseus. The bark of Alstonia scholaris is a febrifuga. Holarrhena antidysentrica yields a drug which is a cure for amoebic dysentery.
- Rubber: Many species of Hancora, Dyera, Urceola are the sources of rubber.
- Poisonous: The seeds of Thevetia contain Thevetine a poisonous glycoside. The latex of Acokanthera is used for poisoning arrows. The bark and wood of Nerium indicum provide rat-poison.
- Ornamental: Nerium, Catharanthus (syn. Vinca), Thevetia, Wrightia, Allamanda are cultivated in gardens as ornamentals.
Affinities of Apocynaceae:
The family Apocynaceae is closely related to Asclepiadaceae and has been placed with it by taxonomists. Hallier included the Asclepiadaceae with the Apocynaceae and derived them from the Linaceae. Bessey accepted the two families as distinct and treated both in his Gentianales. Hutchinson placed the family in his order Apocynales and considered it to be derived from stock ancestral to Loganiaceae.
Carissa congesta Wight.
Shrubs, 2-3 m tall, tap root, Aerial, erect, branched stem with spiny branches, leaves 3-7×2.5-5 cm, elliptic or obovate, subacutebat base, obtuse and often mucronate at apex. Flowers white fragrent, in pubscent, terminal corymbose-cyme, . Fruits 1.5-2.0 cm long, 4 or more seeded, purplish black when ripe.
Flowering and fruiting- February- May
Cascabela thevetia L.
Shrubs, 3-5 M tall, tap root, Aerial, erect, branched stem with milky latex. Leaves linear, lanceolate, acute at apex. Flowers bright yellow, 3-4 CM across infandibulliform, in axillary, few flowered cymes. Fruits ellipsoid oblong with 4 insecure angles.
Catharanthus roseus (L.) G. Don
Perennial herb,Root Branched tap root system Stem Herbaceous erect, cylindrical, solid, branched, glabrous, and green. Leaves Cauline, ramal, opposite decussate, simple, exstipulate, petiolate, ovate, entire acute, unicostate reticulate venation. Inflorescence Solitary axillary or in pairs. Flower Bracteate, pedicellate, complete, hermaphrodite, actinomorphic, pentamerous, hypogynous, pinkish white. Bicarpellary, syncarpous, ovaries free at the base, but united at the stigmatic region, unilocular with marginal placentation, superior, two large green nectaries antero-posterior to the ovary; style filiform with dumbell shaped stigma.
Nerium oleander Mill.
Evergreen shrub with latex. Root Branched tap root. Stem Erect, woody, solid, cylindrical, branched, smooth with milky latex. Leaves Whorled, simple, sub-sessile, exstipulate, lanceolate, entire margin, acute, leathery, unicostate reticulate. Inflorescence Terminal cymes. Flower Bracteate, pedicellate, complete, hermaphrodite, actinomorphic, pentamerous, hypogynous, red, pink or white. Bicarpellary, syncarpous, superior, bilocular, axile placentation, style long, stigma drum shaped.
Evergreen shrub, 6-7 foot The many branches tend to grow almost parallel to the ground stems exude a milky latex. The large in length and about 2 inches in width shiny leaves, deep green and are 6 or more inches.