''Drypetes wightii'' is an evergreen tree

species In biology, a species is the basic unit of classification and a taxonomic rank of an organism, as well as a unit of biodiversity. A species is often defined as the largest group of organisms in which any two individuals of the appropriate s ...

endemic to the Western Ghats, India. The species is considered Vulnerable under the '' IUCN Redlist of Threatened Species''.

Description

Drypetes wightii in Anamalais IMG 20210130 114127

The species occurs as small trees up to 12 m tall. The bark and trunk appear whitish. The trees have a characteristic horizontal branches, with cylindrical branchlets. Branchlets and leaves lack hairs. The leaves are simple, alternate, and

distichous In botany, phyllotaxis () or phyllotaxy is the arrangement of leaves on a plant stem. Phyllotactic spirals form a distinctive class of patterns in nature. Leaf arrangement The basic arrangements of leaves on a stem are opposite and alternat ...

, with short petioles about 0.2 - 0.6 cm long. The leaf blade is sub-coriaceous, about 4-9 cm long by 1.5 to 3.5 cm wide, dark green, drying pale greenish to brown. The shape of the leaves is elliptic with a slight asymmetric base and an acuminate apex. The margin is entire. The leaves have a midrib that is flat above. Leaves have 6-9 pairs of secondary nerves. The flowers are

unisexual Dioecy (; ; adj. dioecious , ) is a characteristic of a species, meaning that it has distinct individual organisms (unisexual) that produce male or female gametes, either directly (in animals) or indirectly (in seed plants). Dioecious reproductio ...

, with male flowers in axillary clusters from pedicels about 3-5 mm long, puberulous and 4 to 5 tepals about 3 x 2-2.5 mm in size, 6-10 stamens that are about 1-1.5 mm long. The stamen filaments are free, with oblong anthers. The female flowers are also axillary, but solitary, with pedicels 4-5 mm long, puberulous and 4-5 tepals about 3-4 × 2.5-3.5 mm in size; disc annular and reniform stigma. The ovary is about 2 x 1 mm, ellipsoid and with a single locule with two ovules, sparsely puberulous to glabrous. The fruit is a

drupe In botany, a drupe (or stone fruit) is an indehiscent fruit in which an outer fleshy part (exocarp, or skin, and mesocarp, or flesh) surrounds a single shell (the ''pit'', ''stone'', or '' pyrena'') of hardened endocarp with a seed (''kernel'') ...

, ovoid to ellipsoid in shape, about 1.7-2 cm long by 1.5 cm wide, smooth and hair-less, with a pedicel about 10-12 mm long and holding a single seed.

Range

The species occurs in the Western Ghats mountains in the states of Tamil Nadu and Kerala from Wynaad and the Nilgiris in the North to the Anamalai Hills. It occurs between 900 and 1500 m.

Habitat

The trees occur in mid-elevation (900 to 1500 m) tropical wet evergreen forests of the Western Ghats.

Ecology

The species is considered rare and is found in the understorey of taller trees. It has been reported to occur at a density of 6 to 24 stems per hectare in tropical wet evergreen forests in different locations.

Etymology

The specific epithet derives from

Robert Wight Robert Wight Doctor of Medicine, MD Fellow of the Royal Society, FRS Linnean Society of London, FLS (6 July 1796 – 26 May 1872) was a Scottish surgeon in the East India Company, whose professional career was spent entirely in southern India, ...

, whom the species is named for. In Malayalam, the species is called ''vellakasavu''.

References

wightii Plants described in 1922 {{Malpighiales-stub