''Mitrephora calcarea '' is a species of plant in the family Annonaceae. It is native to

Laos Laos (, ''Lāo'' )), officially the Lao People's Democratic Republic ( Lao: ສາທາລະນະລັດ ປະຊາທິປະໄຕ ປະຊາຊົນລາວ, French: République démocratique populaire lao), is a socialist ...

and Vietnam. Aruna Weerasooriya 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 provided the first valid formal description of the species, named it after the limy ( in Latin) soil it grows in. The name follows a prior invalid account by

Suzanne Jovet-Ast Suzanne Jovet-Ast (born 1914) was a French botanist, who worked principally at the National Museum of Natural History, France. Life Suzanne Ast was born in Paris, France, on 8 February 1914. She received her Baccalauréat (1932) from Lycée ...

, which lacked a Latin description.

Description

It is a tree. Its branches have

lenticel A lenticel is a porous tissue consisting of cells with large intercellular spaces in the periderm of the secondarily thickened organs and the bark of woody stems and roots of dicotyledonous flowering plants. It functions as a pore, providing a ...

s and sparsely covered in fine light brown hairs. Its oval to lance-shaped, leathery leaves are 7.5-14 by 3-5 centimeters with pointed bases and tips. The upper surfaces of the leaves are hairless while their undersides are slightly hairy. The leaves have 7-15 pairs of secondary veins emanating from their midribs with noticeable interconnecting tertiary veins. Its petioles are 3.5-8.5 by 1.2-2.3 millimeters and covered in sparse, brown hairs. Its flowers are born opposite the leaves on inflorescences in groups of 3 or fewer. The flowers are on a fleshy, densely hairy

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 5-7 by 1.2-2.2 millimeters. The pedicels have an oval, basal

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 ...

that is 2 by 2 millimeters, and another bract at their midpoint that is 2.3-3 by 2.4-2.6 millimeters. Its flowers have 3 brown, 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 4-6 by 3-3.5 millimeters. The outer surface of the sepals is densely hairy, while their inner surfaces is hairless except at the tips. Its 6 petals are arranged in two rows of 3. The white, oval to lance-shaped outer petals are 17-21 by 8.5-10.5 millimeters and come to a point at their tip. The outer surfaces of the outer petals are densely hairy, while their inner surfaces are slightly hairy. The margins of the outer petals become wavy when mature. The reddish, inner petals are 12-13.5 by 7-9 millimeters. The inner petals have a basal claw and a rhomboidal blade. Its flowers have more than 100 yellow stamens that are 1-1.2 by 0.4-0.6 millimeters. Its flower have 4-6

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 1.3-1.5 by 0.6-0.8 millimeters and covered in fine hairs. Its stigma is shaped like a narrow, inverted cone. The carpels have 8-12 ovules arranged in two rows. The fruit are born on woody pedicels that are 7.5-12 by 1.7-3.2 millimeters. The oblong, smooth, dull grey-blue, fruit occur in groups of 2-4 and are 3.3-4.2 by 1.4-1.7 centimeters and covered in dense, fine hairs. The fruit have up to 8 oval, brown seeds that are 11 by 8 millimeters.

Reproductive biology

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

Habitat and distribution

It has been observed growing in limestone forests at elevations of 100 meters.

References

{{Taxonbar, from=Q17140084 calcarea Flora of Laos Flora of Vietnam Plants described in 2005 Taxa named by Richard M.K. Saunders