| Euphorbia herbstii | |
|---|---|
| Conservation status | |
|
Critically Imperiled (NatureServe) |
|
| Scientific classification | |
| Kingdom: | Plantae |
| (unranked): | Angiosperms |
| (unranked): | Eudicots |
| (unranked): | Rosids |
| Order: | Malpighiales |
| Family: | Euphorbiaceae |
| Genus: | Euphorbia |
| Species: | E. herbstii |
| Binomial name | |
| Euphorbia herbstii (W.L.Wagner) Oudejans |
|
| Synonyms | |
|
Chamaesyce herbstii W.L.Wagner |
|
Euphorbia herbstii (syn. Chamaesyce herbstii)[1] is a rare species of flowering plant in the euphorb family known by the common name Herbst's sandmat. It is endemic to Oʻahu, Hawaii, where it is rapidly disappearing.[2] Like other Hawaiian euphorbs, this plant is known locally as ʻakoko. It is a federally listed endangered species of the United States.
This plant is usually a tree which can grow up to 8 meters tall. The leaf blades are long and narrow, and the branches bleed a milky sap. The inflorescence is a cluster of cyathia.
This species is known from perhaps four populations[3] in mesic forests on the Waiʻanae Range.[2] Since the year 2000 the plant has undergone a severe decline, with populations extirpated and remaining ones becoming smaller.[2] The exact number of remaining plants is unknown because each survey tallies fewer individuals, while more have been planted in appropriate habitat.[2]
Threats to the species include feral pigs, which uproot and trample vegetation, leading to loss of plant cover and root networks, which then leads to erosion.[2] They pick up the seeds of invasive plant species and transport them to new habitats.[2] Fences have been erected in critical areas to exclude the pigs.[2] Non-native plants affecting the euphorb include silky oak (Grevillea robusta), corky-stem passionflower (Passiflora suberosa), and strawberry guava (Psidium littorale).[2]