Apocynaceae

Chapter: Pharmacognosy and Phytochemistry : Study of Different Families

A British systematic botanist J. Hutchinson published his work, The Families of Flowering Plants in 1926 on dicotyle-dons and in 1934 on monocotyledons. Hutchinson made it clear that the plants with sepals and petals are more primitive than the plants without petals and sepals on the assumption that free parts are more primitive than fused ones.

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APOCYNACEAE

· Habit: These are mostly twining or erect shrubs and lianes, a few herbs and trees with latex. Bicollateral bundles or internal phloem often present.

· Leaves: The leaves are simple, opposite or whorled, rarely alternate.

· Flowers: The flowers are regular, bisexual and hypogy-nous, in cymes. They are usually salver or funnel shaped, often with corona.

· Calyx: The sepals are five in number, and rarely four, gamosepalous and often united only at the base.

· Corolla: There are five petals, rarely four. They are gamopetalous and twisted.

· Androecium: There are five stamens, rarely four. They are epipetalous, alternating with the petals, included within the corolla tube. The anthers usually connate around the stigma and apparently adnate to it. The disc is ring like or glandular.

· Gynoecium: The carpels are two or (2), apocarpous or syncarpous, superior. When apocarpous, each ovary is one-celled with marginal placentation, and when syncarpous the ovary may be one celled with parietal placentation, or two celled with axile placentation. There are 2-∞ ovules in each.

· Fruit: There is a pair of follicles, barriers or drupes

· Seeds: The seeds often have a crown of long, silky hairs and they mostly have endosperm.