Oldenlandia lancifolia (Schumach.) DC.

Global description

Oldenlandia lancifolia is an annual to perennial herbaceous plant of short duration. The stem is erect or spreading, cylindrical, glabrous, bearing simple opposite subsessile leaves, with a narrowly linear blade, wedge-shaped at the base and acuminate at the top. At the base of the leaves is a stipular collar with 2-5 teeth. The flowers are axillary, usually solitary, long-stalked. The calyx is a 4-lobed cup, the corolla is white, forming a tube with 4 lobes on top. The fruit is a globose capsule, wider than long, with a short beak.

General habit

Oldenlandia lancifolia is a very delicate herbaceous plant, from 10 to 70 cm (100 cm) high, spreading or erect, which can form a carpet on the ground. It is often very branched towards the base, with the secondary branches themselves being poorly branched or even simple.

Underground system

The main root is taproot. Adventitious roots may develop at the lower nodes of the stems in contact with the soil.

Stem

The stem is slender, cylindrical or obscurely quadrangular and glabrous.

Leaf

The leaves are simple, opposite, sessile or subsessile with a petiole 0-2 mm long, horizontally spread. At the base of each pair of leaves is a stipular collar forming a small cup topped by 2-5 teeth, 1-3 mm long, longer than the cup. The leaf blade is narrowly elliptic to linear, rarely elliptic, 10-70 mm long and 2-6 (12) mm wide. It is uninervate. The apex is acuminate and the base acute wedge-shaped. The entire margin is finely scabrous, the upper surface finely scabrous and the lower surface glabrous.

Inflorescence

The flowers are solitary or more rarely in groups of 2-3.

Flower

The flowers are borne on separate 5-10 mm long pedicels. The calyx is cupped at the base, topped by 4 triangular lobes, 1 to 1.5 mm long, acuminate at the apex. The corolla is white, sometimes tinged with purple or pink, fused at the base into a tube 1 mm long, topped by 4 triangular lobes 1 to 2 mm long. The throat of the tube is hairless. The 4 stamens are inserted into the tube. The style extends only slightly beyond the corolla tube.

Fruit

The fruit is a subglobose capsule, clearly wider than long, depressed in the middle, with 2 chambers. It is 1.2 to 3 mm long and 3.2 to 5 mm wide, enclosed in the calyx and topped by the 4 lobes. At the top there is a short beak of 1 mm.

Seed

The seeds are 0.3 to 0.4 mm in diameter, angular, highly reticulated and light brown in colour.

Origin

Oldenlandia lancifolia is native to tropical Africa and Madagascar. It is also present in Mauritius but not in Réunion.

Worldwide distribution

This species has been introduced throughout Central America, the northern half of South America and in the Caribbean islands.

https://www.gbif.org/species/2916221