Aloe armatissima

Overview

Aloe armatissima is a highland aloe of southwestern Saudi Arabia. It is principally solitary, with strongly toothed leaves and erect inflorescences; flowers are mainly yellow, with pink and red also recorded. [1, 2, 3]

Classification and nomenclature

Accepted name: Aloe armatissima Lavranos & Collen. [3]
Protologue bibliography: Cact. Succ. J. (Los Angeles) 72: 22 (2000). [3, 1]
Type locality and type material: Saudi Arabia, Hijaz Province, near Ash-Shafa, between Al-Hadda and Taif; collected 4 August 1982; Collenette 3738; holotype K. [1, 2]

Etymology

The epithet armatissima refers to the extremely heavily armed leaf margins and derives from the superlative of Latin armatus, “armed”. [1, 4]

Key characteristics

Growth form

Usually solitary and acaulescent, but rarely dividing into 2–3 rosettes; old plants may develop a short stem. [1, 2]

Leaves

Leaves form a dense rosette and are erect to arcuate-ascending, reaching up to 50 cm long and 9–17 cm wide at the base. The upper surface is pruinose and pale green to grey. [1, 2]

Leaf surface and margin

Juvenile leaves can be heavily white-spotted. The margins carry conspicuous, hard, pungent, white deltoid teeth about 5 mm long with brown tips. [1, 2]

Inflorescence and flowers

Inflorescences are erect, with 1–2 produced simultaneously. Open flowers are nodding; the perianth is cylindrical-trigonous and pruinose, mainly yellow and rarely pink or red. [1, 2]

Distribution

Endemic to southwestern Saudi Arabia, in small discontinuous colonies from a few kilometres north of Taif southwards along the Great Arabian Escarpment to Wadi Sakharh and Jabal Ibrahim. [3, 1]

Habitat

It grows on granite at about 1,400–1,890 m, on gravelly slopes and among granite boulders. In places it occurs in juniper forest; annual rainfall is estimated at about 120–160 mm. [1]

Main references

McCoy, T. (2019). The Aloes of Arabia. McCoy Publishing, Temecula, California. pp. 91–95.
Carter, S., Lavranos, J.J., Newton, L.E. & Walker, C.C. (2011). Aloes: The Definitive Guide. Royal Botanic Gardens, Kew. p. 355.
World Checklist of Vascular Plants (WCVP).
Grace, O.M., Klopper, R.R., Figueiredo, E. & Smith, G.F. (2011). The Aloe Names Book. Strelitzia 28. South African National Biodiversity Institute, Pretoria. p. 16.

Updates

Classification, distribution and descriptive information are revised as new sources are verified or taxonomic treatments change.