CONVOLVULACEAE - The Bindweed Family
This is a Family with about 1800 species in 50 genera found in temperate and tropical regions of the world. In dry Mediterranean or semi-desert climates, they are mostly woody shrubs, and in rich, bushy vegetation or open, drier places, they are usually climbers with long trailing or twining stems. There are one or two trees, and some species grow in almost pure sand on tropical beaches. They are often weeds, e.g. Hedge Bindweed (Calystegia sepium) and Field Bindweed (Convolvulus arvensis), and sometimes parasitic, e.g. Common Dodder (Cuscuta epithymum). Plants which may be weeds in their native country are sometimes grown as ornamentals, and there are now many hybrids of Ipomoea purpurea grown in gardens. The Sweet Potato (Ipomoea batatas) is an important food plant in the tropics, and some species have medicinal uses.
Characteristics of this Plant Family:
Leaves, Stem & Roots ~ In parasitic species, the stems are soft and stringy and produce roots that grow into the host plant to gain nutrients. The parasitic species have no green pigment and no leaves. The stems of shrubs may be woody, and the stems of climbing species may reach several feet. Roots are often swollen or stringy rhizomes, and it is because these are able to regenerate new plants from small pieces that the plant is able to spread so easily, especially in cultivated ground. The leaves are alternate and very variable in shape, but are usually simple and heart-shaped. The Sweet Potato is a tuber produced at the nodes of the creeping stems of the plant, and can weigh as much as 3kg.
Flowers ~ The flowers are regular and often have an involucre of bracts under them. The flowers are borne in the leaf axils, often singly, but in a spike in Spanish Flag (Ipomoea lobata), where they also differ in shape. There are five free sepals forming the calyx, and the flowers have five petals usually joined to form a trumpet. There are five stamens joined to the base of the tube.
Seeds ~ The ovary is superior, and the fruit is a capsule, usually dehiscent. It often contains five large woody seeds. Sometimes, the seeds may be hairy.
Members of this Family usually have:
Trumpet-shaped flowers with five fused petals
Five stamens fused to the base of the trumpet
Simple leaves growing alternately up the stem
and are often trailing or climbing weeds
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