Gonialoe is a genus of three species that were previously included in the genus Aloe. Following molecular research on the generic-level relationships among the alooids, the genus Aloe was split into several segregate genera: Aloe (true aloes), Aloiampelos (rambling aloes), Aloidendron (tree aloes), Aristaloe (awn-leaf aloe), Gonialoe (variegated or kanniedood aloes), and Kumara (fan aloes).With only three species, Gonialoe is among the smallest of the alooid genera. Gonialoe was originally described at subgenus level as Aloe subgen. Gonialoe by John Gilbert Baker (1834–1920) in 1880 and raised to genus level in 2014. The name Gonialoe is derived from the Greek gonia, meaning ‘an angle’ and the genus name Aloe, in which these plants were originally described, i.e. ‘aloes with angled leaves’. It likely refers to the leaves that are v-shaped (or angled) in cross-section, which is unlike the smoothly rounded leaves (in cross-section) of most other aloes.

Plants consist of small stemless rosettes that either grow solitary or sucker to form small to dense groups. The prominently keeled and lengthwise-folded leaves are arranged in three rows, and are carried erect to spreading or almost horizontally. The three-ranked leaves of the variegated aloes are unique among the aloes, as all other aloes have leaves in rosettes or rarely in two rows (especially in young plants). Leaves are greenish to brownish in colour and variously marked with white confluent spots, often in transverse bands, giving the leaves a mottled appearance. The keel and leaf margin have a bony whitish edge with minute white teeth or can be almost without teeth. This is unlike the often fiercely toothed leaf margins of most other aloes.

Fig. 2. Three-ranked, strongly keeled leaves of G. dinteri with finely toothed margins (left). Photo by E.J. van Jaarsveld and G. variegata with entire margins (right). Photo by N.R. Crouch

Inflorescences of the variegated aloes are erect and can be unbranched or up to 8-branched. The flower clusters (racemes) are usually rather lax and cylindrical, with reddish to pinkish flowers that can be dull or brighter pink, depending on the species. Flowers are cylindrical and slightly decurved with a constriction above the ovary before it widens towards the mouth. Flower buds are horizontal to pendent, while open flowers are pendent.

Fig. 3. Racemes and flowers of G. dinteri (left). Photo by E.J. van Jaarsveld and G. variegata (right). Photo by S.P. Bester

The 3-capsuled fruits dry out and split open at maturity to release small seeds. The seeds have prominent pale wings and are wind dispersed. Gonialoe sladeniana rarely produces seed, which leads to a very slow recruitment rate in this species.

Fig. 4. Gonialoe variegata dried capsules with seeds (left). Photo by J.C. Kruger and winged seeds (right). Photo by G. Nichols.

Species

Gonialoe dinteri (A.Berger) Boatwr. & J.C.Manning (=Aloe dinteri A.Berger)
Plants form solitary, stemless rosettes. Leaves are chocolate brown to deep brownish green, strongly keeled and folded lengthwise, and spreading to almost horizontal, up to 30 cm long, and ± 8 cm wide. The margin and keel of the leaf have a white, bony edge with minute white teeth. Pale rose pink, white-tipped flowers (28–30 mm long) with a bluish bloom are borne in 3- to 8-branched inflorescences (up to 0.9 m high) consisting of a slender peduncle (inflorescence stalk) carrying cylindric, lax racemes (flower heads) between January and March. The bracts on the inflorescences are 3-nerved and shorter than the pedicels (flower stalks). This species is only known from northwestern Namibia and southwestern Angola. It usually grows in sandy or rocky ground or wedged in cracks in limestone or in the shelter of small bushes. It is also sometimes found on granite in the bushveld near the edge of the Namib Desert. The habitat receives very low summer rainfall.

Fig. 5. Gonialoe dinteri. Photo by P. Winter

Gonialoe sladeniana (Pole-Evans) Boatwr. & J.C.Manning (=Aloe sladeniana Pole-Evans)
Plants form small groups of stemless rosettes. Leaves are deep green to gey-green, deeply keeled and slightly folded lengthwise, and rather erect to ascending and tightly bunched together, up to 9 cm long, and ± 4 cm wide. The margin and keel of the leaf have a whitish, bony edge with minute white teeth. Dull pink, green-tipped flowers (20–30 mm long) are borne in usually unbranched to rarely 1- or 2-branched inflorescences consisting of a slender peduncle (inflorescence stalk) carrying cylindric, rather lax racemes (flower heads) between January and February. The bracts on the inflorescences are 1-nerved and shorter than the pedicels (flower stalks). This species is restricted to the mountains of the western escarpment in west-central Namibia. It usually grows on decomposed granites. The habitat has very cold winters, and the distribution falls in the area where low amounts of winter rain gives way to little rain in summer.

Fig. 6. Gonialoe sladeniana. Photo by E.J. van Jaarsveld

Gonialoe variegata (L.) Boatwr. & J.C.Manning (=Aloe variegata L.)
Plants form stemless rosettes that occur solitary or form small to dense groups. Leaves are green to brownish, keeled and slightly folded lengthwise, sometimes with a spiral twist, and rather erect to ascending, up to 15 cm long, and ± 6 cm wide. The margin and keel of the leaf have a whitish, bony edge with very minute white teeth and is often almost entire (without teeth). Dull pink to red, rarely yellow flowers (35–45 mm long) are borne in unbranched to usually 1- or 2-branched inflorescences consisting of a stout peduncle (inflorescence stalk) carrying cylindric, lax racemes (flower heads) between July and September. The bracts on the inflorescences are 1-nerved and longer than the pedicels (flower stalks). This species is widespread from southern Namibia, through the Northern Cape, eastern parts of the Western Cape, western parts of the Eastern Cape, and just entering the western Free State, South Africa. It grows on clayey soils or rarely soils of decomposed granites, in Karoo vegetation and on the edge of the Namib Desert, usually in the protection of bushes. The habitat generally has cold winters, and the distribution falls within both the summer and winter rainfall regions.

Fig. 7. Gonialoe variegata. Photo by S.P. Bester