Spermacoce pusilla Wall.

Code

SPCPU

Growth form

broadleaf

Biological cycle

annual

Habitat

terrestrial

Global description

Spermacoce pusilla is an annual or short lived perennial grass with quadrangular, semi-decumbent or more or less erect stems, branched, reaching 30 to 50 cm long. The leaves are opposite or in false whorls, sessile or sub sessile, with linear-lanceolate lamina, 1 to 5 cm long and 2.5 to 5.5 mm wide, finely scabrous on the upper side. The many small flowers with white or pink corolla are gathered in globular glomerules, 1 to 1.5 cm in diameter at the nodes. The fruits are small, ellipsoid capsules about 1.5 mm long.
 
General habit

Spermacoce pusilla is an annual or short lived perennial grass, semi-decumbent or more or less erect, branched, often reddish, reaching 30 to 50 cm long.
 
Underground system

Taproot.
 
Stem

The stem is quadrangular, solid, more or less branched, often reddish in color and more or less puberulous.
 
Leaf

The leaves are simple, sessile to sub sessile, opposite, decussate, appearing whorled. The lamina is linear-lanceolate to narrowly lanceolate, 1 to 5 cm long and 2.5 to 5.5 mm wide, with acuminate apex and attenuate base, finely scabrous on the upper face and glabrous on the underside; at the base, is a stipular collar, 1.5 to 2 mm long, glabrous or hairy.
 
Inflorescence

The inflorescences are globular dense glomerules, 1 to 1.5 cm in diameter, at the nodes; many filiform bracteoles, about 2 mm long.
 
Flower

The flowers are small, 1.8 to 2.4 mm long, calyx in tube about 1 mm long, topped by four lobes with acuminate top. The corolla is white, purple or pink, in narrow tube of about 1.3 mm long, with triangular or lanceolate lobes, 0.8 to 1.1 mm; stamens are equal or longer than the petals, anthers about 0.3 mm long; ovary is with 2 loculus, with filiform style as long or longer than the petals.
 
Fruit

The fruit is an ellipsoid to oblong capsule, about 1.5 mm long
 
Seed

The seeds are oblong or oblong-ellipsoid, 1.3 mm long and 0.55 mm wide, with a large ventral furrow, brown in colour.

Madagascar: Spermacoce pusilla blooms during the period from January to April.

Spermacoce pusilla is an annual or short-lived perennial grass; it is propagated by seed. They are spread by water and tillage tools.

Spermacoce pusilla could be mistaken for Spermacoce laevis Lam. ; the latter has clearly erect growth habit and lanceolate leaves, wider in the middle and without pseudo-whorls.
Moreover, Spermacoce filifolia (Schumach. & Thonn.) J. P.Lebrun & Stork, with its erect growth habit, has very narrow, filiform leaves.

Madagascar: Spermacoce pusilla grows on ferralitic soils, alluvial soils, of low to medium fertility, in sunny places. It is a weed of peanut, cassava and rainfed rice, in semi-intensive cultural system. It is also found in fallows, degraded savannas or places found in sub-humid areas in West and Middle East, up to 1000 m altitude.
Mauritius: Absent.
Reunion: Absent.

Local harmfulness

Madagascar: Spermacoce pusilla is a weed infrequent and often scarce in crops. It does not present any particular difficulty. S. pusilla remains a weed of dry crops on more or less degraded land on slopes in sub-humid areas but often scarce.

Local control

Madagascar: Spermacoce pusilla is eliminated by manual weeding with angady in cassava or groundnuts cropping systems.

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