Turnera subulata is a species of flowering shrub in the passionflower family known by the common names white buttercup, sulfur alder, officialsilva, dark-eyed turnera, and white alder. Despite its name, it is not related to buttercups or alders. It is native to Central and South America, from Panama south to Brazil. It is also known as an introduced species in many other places, such as Malaysia, Indonesia, several other Pacific islands, the Caribbean, and Florida in the United States.

This plant is found growing wild in abandoned land, fields, cemeteries, and along waterways, and grows in clusters. It generally grows in dry, sandy areas at elevations of 10-250 m above sea level, in places exposed to direct sunlight or with some shade.

• This plant is an annual herb that grows from a thick taproot and a woody stem base.

• The stem reaches a maximum height of about 80 cm (31 in).

• The leaves are oval with serrated edges. The underside is slimy and covered with white hairs. The upper surface may also be slightly hairy. The leaves are up to 9 cm (3.5 in) long.

• Flowers appear in the leaf axils, within the hairy, glandular sheaths. The flowers are disc- to funnel-shaped, and the petals are rounded to oblong, the longest exceeding 3 cm (1.2 in). They are white or yellowish with a darker base. The dark spots at the base are nectar guides. The center of the flower is rough, feeling like a cat's tongue. The flowers are year-round, and tend to open in the morning and close around 11 a.m.

• The fruit is a hairy capsule containing seeds with white arils.

• The seeds are dispersed by ants, which may be attracted to their high lipid content.

• Propagation by seed and stem cuttings. Cut a stem section 8-10 cm long. Plant the plant in a hole 5 cm in diameter and 5 cm deep.

• Medicine for duodenal ulcers, gastric ulcers, rheumatism and swelling of the joints, antibiotics (Staphylococcus aureus) and headaches.

• Saponins, flavonoids, alkaloids, tannins, phenolic compounds, amino acids, terpenoids, cardiac glycosides.