''Mitrephora winitii'' 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. It is native to

Myanmar Myanmar, ; UK pronunciations: US pronunciations incl. . Note: Wikipedia's IPA conventions require indicating /r/ even in British English although only some British English speakers pronounce r at the end of syllables. As John C. Wells, Joh ...

and

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 ...

William Grant Craib William Grant Craib (10 March 1882 in Banff, Aberdeenshire – 1 September 1933 in Kew) was a British Botany, botanist. Craib was Regius Professor of Botany (Aberdeen), Regius Professor of Botany at Aberdeen University and later worked at the Ro ...

, the British botanist who first formally described the species, named it after Phya Winit Wanandor, the Thai botanist who collected the specimen that Craib examined. In the

Prachuap Khiri Khan Prachuap Khiri Khan ( th, ประจวบคีรีขันธ์, ) is a town in western Thailand. It is the capital of Prachuap Khiri Khan Province and is on the coast at one of the narrowest stretches in Thailand, only from the border ...

province of Thailand it is commonly referred to as Mahaphrom.

Description

It is a tree reaching 10 meters in height. Its leathery, oval to lance-shaped leaves are 11–13.5 by 5–5.6 centimeters with blunt tips. The leaves are smooth on their upper surfaces while their undersides lighter in color and hairy. The base of its leaves are rounded to heart-shaped and their tips are pointed to slightly tapered. The leaves have 11–13 pairs of secondary veins emanating from their midribs. Its petioles are 4.5–6.5 by 2–2.5 millimeters and covered in fine soft hairs. Its

inflorescence An inflorescence is a group or cluster of flowers arranged on a stem that is composed of a main branch or a complicated arrangement of branches. Morphologically, it is the modified part of the shoot of seed plants where flowers are formed o ...

s are composed of up to 3 flowers on a

rachis In biology, a rachis (from the grc, ῥάχις [], "backbone, spine") is a main axis or "shaft". In zoology and microbiology In vertebrates, ''rachis'' can refer to the series of articulated vertebrae, which encase the spinal cord. In this c ...

that is densely covered in long, soft, pale brown hairs. Each flower is born on a fleshy

pedicel Pedicle or pedicel may refer to: Human anatomy *Pedicle of vertebral arch, the segment between the transverse process and the vertebral body, and is often used as a radiographic marker and entry point in vertebroplasty and kyphoplasty procedures ...

that is 10–16 by 2–3.5 millimeters and densely covered in fine brown hairs. Oval

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 at the base of pedicels are 7–7.5 by 5–8 millimeters while those at the top are 8–10 by 8–10 millimeters. Its flowers have 3 oval

sepals 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 ...

that are 7.5–10 by 7.5–11 millimeters. The outer surfaces of the sepals have dense, brown hairs; the inner surfaces are hairless or nearly so. Its 6 petals are arranged in two rows of 3. The white to cream-colored, oval, outer petals are 3.7–4 by 2.2–3 centimeters with pointed tips. The outer surfaces of the outer petals have dense, fine, brown hairs; the inner surfaces have sparse fine hairs that are denser toward the tip. The inner petals are white to cream-colored with purple stripes and are 2.8–3.2 by 2.2–2.5 centimeters. The inner petals are covered in sparse, fine hairs on both surfaces. Its

stamens 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 ...

are 2–2.2 by 0.8–1 millimeters. Its flowers have up to 10

carpels 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'' ...

that are 2.4–2.6 by 0.8–1 millimeters. Its

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 ...

have 16–18

ovule In seed plants, the ovule is the structure that gives rise to and contains the female reproductive cells. It consists of three parts: the ''integument'', forming its outer layer, the ''nucellus'' (or remnant of the megasporangium), and the fe ...

s. Its fruit are found in clusters of up to 10. The oblong fruit are 1.4–1.8 by 1.1–1.4 centimeters. The fruit are smooth and densely covered in fine pale brown hairs that lay flat against the surface. The fruit are born on 11 by 3.5 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 ...

that are sparsely covered in fine, hairs. The fruit have 4–6 seeds that are 10 by 6.5–7 millimeters.

Reproductive biology

The pollen of ''M. winitii'' is shed as permanent tetrads.

Habitat and distribution

It has been observed growing dry evergreen forests with rocky landscapes at elevations up to 20 meters.

Uses

Bioactive compounds extracted from its leaves and twigs have been reported be

cytotoxic Cytotoxicity is the quality of being toxic to cells. Examples of toxic agents are an immune cell or some types of venom, e.g. from the puff adder (''Bitis arietans'') or brown recluse spider (''Loxosceles reclusa''). Cell physiology Treating cells ...

in tests with cultured human cancer cell lines.

References

winitii Flora of Myanmar Flora of Thailand Plants described in 1922 Taxa named by William Grant Craib {{annonaceae-stub