''Pseudoxandra williamsii'' is a species of plant in the Annonaceae family. It is endemic to Peru.

Robert Elias Fries (Klas) Robert Elias Fries (11 July 1876, Uppsala – 29 January 1966, Stockholm), the youngest son of Theodor Magnus Fries (1832–1913) and grandson of Elias Magnus Fries(1794–1878) and an expert on mushrooms. A Swedish botanist who was a mem ...

, the Swedish botanist who first formally described the species using the

basionym In the scientific name of organisms, basionym or basyonym means the original name on which a new name is based; the author citation of the new name should include the authors of the basionym in parentheses. The term "basionym" is used in both botan ...

''Cremastosperma williamsii'', named it after Llewelyn W. Williams, the Welsh economic botanist, who collected the holotype specimen he examined.

Description

It is a bush. Its shiny, brown, papery leaves are 16-20 by 4-5 centimeters and come to a point at their tips. The mature leaves are hairless on their upper surfaces and lightly hairy on their lower surfaces. The leaves have 10-12 distinct, curved secondary veins emanating from the primary vein. Its petioles are 4-5 millimeters long. Each flower is on a short

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 ...

less than 1 millimeter long. Its flowers have 3 oval-shaped

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 5 by 8 millimeters. The outer surface of the sepals is covered in dense white hairs. Its 6 petals are arranged in two rows of 3. The outer petals 11-12 by 9 millimeters and their outer surface is covered by dense white hairs. The inner petals are 6-7 by 5-6 millimeters and concave. The inner petals are smooth on their outer surface except for a hairy patch running from the base to the tip. It has numerous stamens that are 3.5-4 millimeters long.

Reproductive biology

The pollen of ''P. williamsii '' is shed as permanent tetrads.

References

Flora of Peru williamsii Vulnerable plants Taxonomy articles created by Polbot {{Annonaceae-stub