Aloidendron tongaense (Van Jaarsv.) Klopper & Gideon F.Sm.

Klopper, Ronell R., Crouch, Neil R., Smith, Gideon F. & van Wyk, Abraham E., 2020, A synoptic review of the aloes (Asphodelaceae, Alooideae) of KwaZulu-Natal, an ecologically diverse province in eastern South Africa, PhytoKeys 142, pp. 1-88 : 1

Aloidendron tongaense (Van Jaarsv.) Klopper & Gideon F.Sm.

Syn.

Aloe tongaensis Van Jaarsv.

Description.

Tree, 4-8 m high, with rounded crown. Trunk 60-80 cm diameter at base, erect, dichotomously branched, without persistent dried leaves, with grey bark. Leaves rosulate at branch tips, spreading to recurved, dull green, without markings, leathery, ensiform, upper surface canaliculate, 40-59 cm long, 4.5 cm wide; margin with teeth, 2 mm long, 5-10 mm apart. Inflorescence ± 0.35 m tall, erect, up to 6-branched. Racemes capitate, 4-6 cm long, rather dense. Floral bracts 12-14 mm long, 3-4 mm wide. Pedicels 10-14 mm long. Flowers: perianth yellowish-orange, 47-50 mm long, 8-9 mm across ovary, narrowing very slightly towards mouth, cylindrical, curved; outer segments free for 10 mm; stamens exserted 3-5 mm; style exserted to 7 mm.

Flowering time.

Mainly April-May.

Habitat.

Sand forest and coastal dune forest, in warm, humid, tropical/subtropical conditions, on sandy soil.

Diagnostic characters.

Aloidendron tongaense is one of only two large tree aloes indigenous to KwaZulu-Natal. These two aloes both have dichotomously branched stems that lack persistent dried leaves. Aloidendron tongaense differs from Aloidendron barberae in being a shorter tree (up to 8 m, not up to 18 m) with fewer branches and having smaller dull green leaves of 40-59 cm long (not bright green and 60-90 cm). The inflorescence is also slightly shorter at ± 0.35 m (not 0.4-0.6 m) and up to 6-branched (not 3-branched from a single point), with shorter capitate racemes of 4-6 cm long (not cylindrical and 20-30 cm), bearing curved yellowish-orange flowers that are 47-50 mm long (not straight rose-pink flowers of 33-37 mm) with stamens exserted 3-5 mm at anthesis (not up to 15 mm).

Conservation status.

Least Concern ( Von Staden et al. 2013).

Distribution.

Occurs in the sand forest and coastal dune forest at Kosi Bay in northern KwaZulu-Natal (Maputaland), South Africa and along the southern Mozambique coast as far north as Inhambane, with a known disjunct collection further north in the Cheringoma District of east-central Mozambique (Fig. 4 ). It is a near-endemic of the Maputaland Centre of Endemism ( Van Wyk and Smith 2001).

Notes.

This aloe was previously considered to be a coastal form of A. barberae , but was later accorded species status ( Van Jaarsveld 2010). Although the protologue and subsequent literature states that the species is only known from northern KwaZulu-Natal, South Africa and adjacent areas of southern Mozambique, herbarium specimens indicate that it occurs much wider in Mozambique. In fact, numerous specimens from lowland parts of Mozambique, previously regarded as A. barberae , have now been assigned to A. tongaense ( Walker et al. 2019b).

Figures

Figure 4. Aloidendron tongaense. Photo: N. R. Crouch.