Acalypha crenata Hochst. ex A.Rich.

Code

ACCCR

Life form

Broadleaf

Biological cycle

Annual

Habitat

Terrestrial

Global description

Acalypha crenata is an erect plant with alternate leaves, simple, long petiolate and toothed margins. The inflorescences are axillary spikes, with 3 to 6 female flowers at the base, inserted into a leafy bract with a toothed and ciliate margin, and 4 to 15 very small male flowers at the apex.

Cotyledons

The cotyledons are 7 mm long and 3 mm wide. They are oval and petiolate. Their faces are hairless.

First leaves

The first leaves are simple and petiolated. The lamina is oval in shape, and cunate at the apex. The margin is finely toothed. From the first leaves, the main vein and the secondary veins are visible.

General habit

The plant is erect. The plant develops in a main axis carrying some low ramifications. It can measure up to 45 cm high.

Underground system

The root consists of a main taproot with fine secondary roots.

Stem

The stem is solid and cylindrical, finely striated longitudinally. It is slightly pubescent. In highly developed plants, it can be woody at the base.

Leaf

The leaves are alternate and simple. The blade, oval in shape, is 2 to 5 cm long and 1 to 3 cm wide. It is cunate at the base and at the apex and is attached at the end of a petiole, 2 to 6 cm long. The margin of the limb is toothed. The upper and lower faces are slightly pubescent. From the base of the limb, leave 3 to 5 conspicuous veins.

Inflorescence

The flowers are grouped into axillary inflorescences. Each inflorescence is spike-like with 3 to 6 female flowers, each included in a leafy bract at the base of the inflorescence and 5 to 15 male flowers above the female flowers. The inflorescence is 1 to 2 cm long. The axis is pubescent.

Flower

The bracts surrounding the female flowers are triangular in shape, rounded at the base. At the time of fruiting, the bract is 4 to 5 mm long and 7 to 8 mm wide. The toothed margin has 10 to 18 finely ciliated teeth. The outer surface of the bract is usually glabrous. The female flowers are reduced to a globular ovary with 3 cells, surmounted by a trifid style, laciniated at the top and 4 mm long. The male flowers are reduced to a calyx closed around the stamens. They measure 1 to 2 mm in diameter.

Fruit

The fruit is a capsule with 3 cells, of globular form, with pubescent tegument. It measures 2.5 mm in diameter. Each cell contains a seed.

Seed

The seed is ovoid and is 1 mm long. It is light brown..

Northern Cameroon: In cotton fields, Acalypha crenata is mainly a species of middle and end of the crop cycle. Seedlings occurring in May are rare. They usually take place in June or July. This phase is short, it lasts only 2 to 3 weeks. After weeding or hilling in July, a second germination phase may occur. The vegetation phase is also very short, since the first inflorescences appear 2 to 3 weeks after germination. Flowering is very important from June to August, then decreases and ends in September. In weeded fields, it is slightly delayed. The fructification occurs in July in weedy plots, in September in weeded plots. It ends in October and November with drying out of the plants at the beginning of the dry season.

 

Acalypha crenata is an annual plant. It reproduces by seeds.

The arrangement of female flowers and male flowers  (3-6 female flowers in a bract topped by 4-15 male flowers spike-like) differentiates Acalypha crenata from A. segetalis, of which each female flower is surmounted by a short spike of male flowers.

Northern Cameroon: Acalypha crenata grows in the Sahelo-Sudanian and Sudano-Sahelian regions, with an annual rainfall of between 800 and 1,200 mm. It is characteristic of clay soils such as fersialitic soils, vertisols and lowland soils with a clay content greater than 25% and a neutral to slightly basic pH. It is never found on acidic ferruginous soil. In Northern Cameroon, it is present in 10% of cultivated fields.

Worldwide distribution

Acalypha crenata occurs in northern Nigeria, central Africa (Cameroon, Chad) and eastern Africa (Sudan, Somalia, Uganda).

Local weediness

Northern Cameroon: Acalypha crenata is a potential local species (medium frequency (between 0.5 and 0.2) and moderately abundant (average abundance between 1.25 and 1.5)), rarely abundant.

 

Herbarium pictures ReCOLNAT: https://explore.recolnat.org/search/botanique/simplequery=Acalypha%2520crenata