Acanthus gaed Lindau

M. Thulin et al. Flora of Somalia Vol. 1-4 [updated 2008] https://plants.jstor.org/collection/FLOS

Type

N2, Mt “Serrut” near “Meid”, Hildebrandt 1399 (K iso.)

Morphology General Habit

Shrub, c. 1–3.6 m tall; young stems finely pubescent

Morphology Leaves

Leaves oblong, 5–15 x 2–7 cm, sinuate-lobed, glabrous or almost so, the main veins prominent and excurrent as sharp spines

Morphology Reproductive morphology Inflorescences Bracts

Bracts lanceolate, c. 18–25 mm long, with 3 parallel veins, with spinose tip and spinose-dentate margins, pubescent; bracteoles linear, shorter, with a single midvein, otherwise similar to the bracts

Morphology Reproductive morphology Flowers Calyx

Calyx pubescent; upper lobe 12–18 mm long; lower lobe 15–23 mm long

Morphology Reproductive morphology Flowers Corolla

Corolla pink or mauve with darker veins, c. 25 mm long, pubescent

Morphology Reproductive morphology Flowers Androecium Stamens Filaments

Filaments c. 12 mm long; anthers c. 4 mm long, densely pubescent

Morphology Reproductive morphology Flowers Gynoecium Style

Style c. 14 mm long, hairy at the base

Morphology Reproductive morphology Fruits

Capsule c. 15 mm long, glabrous.

Distribution

N2 not known elsewhere.

Ecology

Altitude range 1350–2060 m.

Vernacular

Gah-ed, ga´id (Somali)

Note

A. gaed has sometimes been regarded as conspecific with A. arboreus Forssk., but this has larger flowers with the corolla 35–50 mm long. A. polystachius Delile in Ethiopia and Sudan is another closely related species with significantly larger flowers (corolla at least 50 mm long).

Vollesen, K. (2007). Synopsis of the Species of Acanthus (Acanthaceae) in Tropical East and Northeast Africa and in Tropical Arabia. Kew Bulletin, 62(2), 233-249. Retrieved from http://www.jstor.org/stable/20443348

Type

Somalia, Mait, Mt Surud, Hildebrandt 1399 (lectotype K!, chosen here; isolectotype BM!).

Distribution

Endemic to the mountains of northern Somalia.

Ecology

Dry montane Juniperus procera forest and scrub with tall undergrowth of Buxus and Dodonaea, steep gullies and dry riverbeds; 1400 - 2100 m.

Conservation

Known only from a small area in the mountains of northern Somalia. The last collection seen is from 1982 but Mats Thulin (pers. comm.) saw the species in 2002 in the same area. He states it was still abundant, and there was no sign of decrease. None of the collectors comment on the species' ability to adapt to disturbance of its natural habitat. All other species in this group seem to tolerate, or even flourish under, a certain amount of human disturbance. The species does not reach dimensions that make it usable as firewood or building poles, and the only threat to its continued existence would seem to be complete clearance of its habitats. Probably Vulnerable (VU) due to limited area of distribution but also currently Data Deficient (DD).

Note

The original material has presumably been destroyed in Berlin and the species is therefore re typified with the Kew sheet chosen as the lectotype. Acanthus gaed could be considered as no more than a small-flowered and small-fruited form of the widespread A. polystachius, but these differences, combined with a huge disjunction in range, justify keeping it as a separate species.