Merremia aegyptia (L.) Urb.

Global description

Merremia aegyptia is lianescent voluble plant, which can reach 3 to 4 meters in length, covered with yellow spiky brown silky hairs. The leaves are alternate, long-stalked, with compound palmate lamina, composed of 5 sessile leaflets, elliptical to lanceolate in shape, wedged base and acuminate or acute apex. The margin is entire. Both sides are covered with yellow brown hairs. The inflorescence is a contracted axillary cyme, driven by a stalk longer than the petiole of the corresponding leaf. It consists of 1 to 9 stalked flowers. The flower is campanulate, white in color, 2 to 3 cm long. The fruit is a globular capsule opening in 4 valves each containing a smooth seed, light brown.
 
Cotyledons

The cotyledons are kidney-shaped, shortly petiolate, broadly emarginate at the top, seeming almost bi-lobed and with a cordate base. They are large in size, broader than long, measuring 20 to 25 mm long and 25 to 30 mm wide. The leaf blade is smooth but marked by 3 to 5 palmate veins emerging from the base.
 
First leaves
 
The first leaves are alternate, palmately compound with 5 sessile elliptical leaflets. The terminal leaflet is the longest. The ribs are clearly marked on the upper face and protruding on the underside. Both sides are covered with yellow brown hairs.
 
General habit
 
Merremia aegyptia is an annual, herbaceous, lianescent and voluble species, with well-branched stem, measuring 3 to 4 meters long and wraps around any medium.
 
Underground system
 
The plant has a taproot system, violet in colour.
 
Stem
 
The stem is cylindrical and solid, 2 to 4 mm in diameter with internodes of 10 to 12 cm long. It is strongly pubescent with long erect hairs, yellow-brown in colour.
 
Leaf
 
The leaves are alternate, compound, and palmate. They are carried by a small stalk, 5 to 10 cm long, usually shorter than the leaf blade and covered with shaggy hairs, yellow brown in color. The palmatisect lamina is composed of 5 sessile leaflets, elliptical in shape with attenuated base in vertex and long acuminate apex. The margin is entire. The upper surface is hairy with long shaggy hairs, yellow brown in colour. The underside is pubescent, mainly along the protruding venations.
 
Inflorescence
 
The inflorescence is an axillary contracted cyme, borne by a shaggy stalk, 15 to 20 cm long (longer than the petiole of the adjacent leaf). The inflorescence comprises 1-9 flowers carried by a pedicel of 1 to 5 cm in length with the base of small bracts lanceolate triangular 3 to 4 mm long, quickly deciduous.
 
Flower
 
The calyx consists of 5 irregular sepals with oval base and acuminate top, 2 cm long. The three outer sepals are hispid and become accrescent at fruiting while two internal sepals are glabrous and narrower and shorter. Corolla is campanulate, formed of five petals fused into funnel, 2 to 3 cm long and 3 to 5 cm in diameter. It is white in colour. The 5 stamens have their filament inserted at the base of the corolla  6 to 8 mm long and do not exceed the corolla tube. The anthers are 3.5 to 4 mm long. The ovary is globular, glabrous, 4 loculus, topped by a threadlike style, as long as stamens, and a bi-lobed stigma.
 
Fruit
 
The fruit is a sub-globular to ovoid capsule, pointed at the top, light brown, 10 to 15 mm in diameter with 4 valves each containing a seed. Under the fruit, are the spreading sepals.
 
Seed
 
Seeds globular, sub-trigonal, 4 mm long, smooth, light brown.

Origin

Merremia aegyptia is native to Central and South America and tropical Africa.

 
Worldwide distribution
 
South and Central America, the USA and South Caraïdes, tropical Africa, Madagascar, India, Pakistan, Southeast Asia, Australia (West and North).