Pilosocereus samanensis


Pilosocereus samanensis is a species of flowering plant in the cactus family Cactaceae, endemic to the northeast of the Dominican Republic. It was first described in 2021. P. samanensis has also been considered to fall within the normal variability of P. polygonus, and so not a distinct species.

Description

Plants of Pilosocereus samanensis have a tree-like habit, tall, with a woody trunk up to tall and across. The primary stem supports 5–10 upright branches, occasionally up to 20, some becoming woody as they age. The stems are across and have 8–9 ribs. They are green when young becoming grey-green with age. The areoles are about across and about apart. Non-flowering areoles initially have a few white hairs up to long which are lost with age. Flowering areoles have many more white hairs. Areoles bear about 12–15 spines, mostly long.
The flowers appear at night. Excluding the style, they are about long. The white style is up to long. The outer perianth segments are rounded and fleshy, about long and wide. The inner perianth segments are white. The fruit is spherical, about across, with red pulp and shiny black seeds.

Taxonomy

Pilosocereus samanensis was first described in 2021. The specific epithet samanensis refers to the Samaná peninsula where this species appears to be restricted. Previously, all the species of Pilosocereus found on the island of Hispaniola were treated as Pilosocereus polygonus. P. samanensis was distinguished from P. polygonus by its shorter height when mature. Its stems are generally thinner. Its spines are shorter. Its areoles also have distinctly shorter tufts of hairs than P. polygonus. It has a mixture of features found in P. polygonus and P. excelsus. P. samanensis has also been considered to fall within the normal variability of P. polygonus, and so not a distinct species.

Distribution and habitat

Pilosocereus samanensis is endemic to the northeast of the Dominican Republic, where it has only been found on the Samaná peninsula. Most of the peninsula has a high rainfall so that the habitat is generally unsuitable for cacti. P. samanensis occurs only on steep rocky cliffs on the coast, along with other xerophytic plants such as Agave and Opuntia.