Turnera ulmifolia L.

Global description
 
Turnera ulmifolia is a sub lignified, erect plant, 20 to 60 cm high. The stem is simple to very branched, woody at the base, cylindrical, brown or reddish in colour. The young branches have a dense pilosity, made of simple, long hairs, usually mixed with shorter, curved bristles and glandular short hairs. The leaves are simple, alternate, stalked, with an elliptical, narrowly oval, lanceolate blade with an acute apex, strongly serrated. The underside is covered with hairs. The flowers are solitary, inserted at the base of the leaves, lemon yellow in color. The fruit is a globular capsule opening at the top.
 
Cotyledons
 
Cotyledons shortly stalked. The lamina is spatulate to oblong, attenuate at the base and rounded at the top, 1.5 cm long and 4 mm wide.
 
First leaves
 
Leaves simple, opposite then becoming alternate, short-stalked. The leaf blade is elliptic with attenuated base and acute apex. The margin is deeply serrated with 5 pairs of large deep tines. The central rib and the lateral alternate ribs are depressed on the upper face. The faces are glabrous.
 
General habit
 
Sub-woody erect plant, branched, 20 to 60 cm high. Young parts are covered with appressed hairs, of a tawny blond, rapidly deciduous, the older parts are glabrous.
 
Underground system
 
Taproot system.
 
Stem
 
The stem is cylindrical, solid, up to 4 to 10 mm in diameter and highly branched. Young stems are covered with simple appressed hairs, mixed with short and curved hairs and glandular hairs. This hairs fall thereafter, making the stems glabrous.
 
Leaf
 
Leaves simple, alternate, carried by a cylindrical petiole, 1.5 to 13 mm long, thinly covered with long appressed hairs. At the base of the petiole are 1 to 2 conical or linear stipules, 0.3 to 0.7 mm long. The leaf blade is elliptic to narrowly oval, very variable in size, 4 to 12 cm long and 1 to 5 cm wide. At the base of the blade are 1 or 2 small prominent glands on both sides of the petiole. The base is attenuated in sharp corner, the apex in acute or acuminate corner. The margin is strongly serrated in the upper 3/4, entire in the lower1/4. The pinnate venation is depressed at the top and sometimes white. The underside is covered with simple, white, appressed hairs, mixed with shorter hairs, sometimes glandular, tiny. The upper side is glabrous.
 
Inflorescence
 
Flowers solitary, axillary, held on a peduncle, 1 cm long, fused to the upper side of the petiole of the corresponding leaf, giving the impression that the flowers are sessile.
 
Flower
 
At the base of the peduncle, is a pair of linear lanceolate bracts, densely dotted with small reddish lines, 12 to 29 mm long and 2 to 5 mm wide, present just at the base of the flower. The calyx, 3 cm long, has 5 sepals fused at the base that ends in 5 large lanceolate acute tines. The corolla consists of 5 large petals, well exceeding the calyx, 16 to 27 mm long and 7 to 13 mm wide, obovate, of a very bright yellow, hairy on both sides, and clawed at the base. 5 stamens, whose base of the filament is fused to the petal. The ovary is sub globular, topped with 3 styles with feathery stigma.
 
Fruit
 
The fruit is a sub globular or broadly oval capsule, with 3 loculus, 3 to 8 mm long and 4 mm wide, dehiscing on the top in three valves with reflected tip, grainy and very densely covered with small tubers at the end, containing numerous seeds.
 
Seed
 
Oblong seed or thickened at the top, slightly arcuate, 2 mm long and 1 mm wide. The seed coat is highly crosslinked, ornated with longitudinal rows of rectangular pits. Aril fleshy, white, lobed, becoming membranous.

Origin

Turnera ulmifolia is native to Central America (Mexico, Costa Rica, Honduras, Guatemala, Nicaragua) and the Caribbean Islands including the West Indies.

Worldwide distribution

This species has been introduced in South America, West Africa, India, South-East Asia, various islands in the Indian Ocean (Seychelles, Madagascar, Reunion, Mauritius), Australia and the Pacific Islands, New Caledonia.
 

https://www.gbif.org/fr/species/2874852