''Goniothalamus aurantiacus'' is a species of

plant Plants are predominantly photosynthetic eukaryotes of the kingdom Plantae. Historically, the plant kingdom encompassed all living things that were not animals, and included algae and fungi; however, all current definitions of Plantae exclud ...

in the family

Annonaceae The Annonaceae are a Family (biology), family of flowering plants consisting of trees, shrubs, or rarely lianas commonly known as the custard apple family or soursop family. With 108 accepted genera and about 2400 known species, it is the largest ...

. It is native to

Thailand Thailand ( ), historically known as Siam () and officially the Kingdom of Thailand, is a country in Southeast Asia, located at the centre of the Indochinese Peninsula, spanning , with a population of almost 70 million. The country is bo ...

. Piya Chalermglin and

Richard M.K. Saunders Richard M. K. Saunders (born 1964) is a botanist. Work Among other subjects, his work has focused on the systematics and evolution of Annonaceae, a Family (biology), family of flowering plants. Legacy He is the authority for the followin ...

, the botanists who first formally described the species, named it after its orange colored ( in Latin) inner petals.

Description

It is a small tree reaching 9 meters in height. Its petioles are 7.5-11 by 1.9-2.7 millimeters and have sparse hairs. Its elliptical leaves have a papery texture and are 23-32 by 5.5-8.5 centimeters with bases and tips that taper to a point. The leaves are hairless on their upper side and have sparse hairs on their underside, particularly on the midrib. The leaves have 14-21 pairs of secondary veins that emanate from the midrib. Its solitary flowers are in axillary positions on 10-13 by 2-3 millimeter

pedicels In botany, a pedicel is a stem that attaches a single flower to the inflorescence. Such inflorescences are described as ''pedicellate''. Description Pedicel refers to a structure connecting a single flower to its inflorescence. In the absenc ...

. The pedicels have 5-9

bract In botany, a bract is a modified or specialized leaf, especially one associated with a reproductive structure such as a flower, inflorescence axis or cone scale. Bracts are usually different from foliage leaves. They may be smaller, larger, or of ...

s. Its flowers have 3 green, oval

sepal A sepal () is a part of the flower of angiosperms (flowering plants). Usually green, sepals typically function as protection for the flower in bud, and often as support for the petals when in bloom., p. 106 The term ''sepalum'' was coined b ...

s that are 5.5-7.5 by 7–9.5 millimeters. The sepals are hairy on their lower surface and hairless on their upper surface. The flowers have 6 petals in two rows of 3. The yellow, elliptical outer petals are 18-28 by 20-22 millimeters. The lower surfaces of the outer petals are hairless at their tips, changing to densely hairy at their bases. The upper surfaces of the outer petals have woolly hairs at their tips changing to hairless at their bases. The orange inner petals are 12-19 by 5.5-9 millimeters. The upper and lower surfaces of the inner petals are densely hairy at their tips changing to hairless at their bases. Its flowers have 50-160

stamen The stamen (plural ''stamina'' or ''stamens'') is the pollen-producing reproductive organ of a flower. Collectively the stamens form the androecium., p. 10 Morphology and terminology A stamen typically consists of a stalk called the filame ...

s that are 2.4-2.8 by 0.6-0.9 millimeters. Its

gynoecium Gynoecium (; ) is most commonly used as a collective term for the parts of a flower that produce ovules and ultimately develop into the fruit and seeds. The gynoecium is the innermost whorl of a flower; it consists of (one or more) ''pistils'' ...

have 4-11 carpels with

ovaries The ovary is an organ in the female reproductive system that produces an ovum. When released, this travels down the fallopian tube into the uterus, where it may become fertilized by a sperm. There is an ovary () found on each side of the body. T ...

that are 2.5-3.8 by 0.6-1 millimeters covered in sparse gold colored hairs. Its pistils lack styles and its stigmas are 2.8-3.6 millimeters long. Its fruit are on 14 by 4 millimeters

. The elliptical, smooth, green fruit are 27-56 millimeters long and have 1-3 seeds. The flat, elliptical seeds are 19-27 by 13–16.5 millimeters with a smooth to wrinkled surface covered in hairs.

Reproductive biology

The pollen of ''G. aurantiacus'' is shed as permanent tetrads.

Habitat and distribution

It has been observed growing in shady areas in forests with evergreen and deciduous trees at an elevation of 250-900 meters.

References

Annonaceae Flora of Thailand Plants described in 2008 Taxa named by Richard M.K. Saunders {{Annonaceae-stub