Nototrichium divaricatum

Nototrichium divaricatum, also known as Na Pali rockwort or kuluʻī (Hawaiian), is a critically endangered perennial shrub in the pigweed family, Amaranthaceae, that is endemic to the island of Kauaʻi in Hawaii.^[2][3] It can only be found in three valleys on the northwestern end of the island, where it grows on north-facing cliffs and ridges.

Nototrichium divaricatum
Nototrichium divaricatum growing in Limahuli Garden and Preserve
Conservation status
Critically Endangered  (IUCN 3.1)[1]
Scientific classification
Kingdom:	Plantae
Clade:	Tracheophytes
Clade:	Angiosperms
Clade:	Eudicots
Order:	Caryophyllales
Family:	Amaranthaceae
Genus:	Nototrichium
Species:	N. divaricatum
Binomial name
Nototrichium divaricatum Lorence

Nototrichium divaricatum are densely branching shrubs that can grow up to 50 cm tall, with most parts covered with silvery-white hairs.^[2] Leaves are oppositely arranged, with leaf blades 3–7.5 cm long and 1–4.6 cm wide. Inflorescences bear several spikes, and are terminal and usually solitary, rarely 2 or 3 together, and compoundly branched. Each spike bears 8–30 small flowers.^[4]

This species was first described in 1996. There are possibly fewer than 3,000 N. divaricatum plants in existence.

Description

This species is characterized by its bushy growth, typically reaching heights of between 0.3 and 2 meters.^[2] Nototrichium divaricatum features densely hairy branches and twigs, giving them a silvery-white appearance. The leaves are arranged oppositely, and have petioles that can vary in size and shape. Each leaf measures approximately 2-7.5 cm x 0.6-4.6 cm.^[5] The plant produces unique flower clusters with multiple branches, and can contain anywhere from 4 to 66 flowers.^[5]

Distribution and habitat

Nototrichium divaricatum is endemic to cliffs and ridges on the northwestern end of Kaua'i, particularly in the Hanalei District and Na Pali coast.^[2] It thrives at elevations of 600 to 1100 meters in areas where remnants of lowland and montane mesic forests are still present.^[5][6] The primary challenges facing Nototrichium divaricatum include damage and habitat loss due to the activities of feral goats, which threaten many endemic species throughout Hawai'i. Additional risks include landslides, rock falls, and non-native plants.^[5]