Aloe × engelbrechtii Gideon F.Sm. & Figueiredo, 2020

Smith, Gideon F. & Figueiredo, Estrela, 2020, Aloe × engelbrechtii (Asphodelaceae subfam. Alooideae), a new South African nothospecies with A. arborescens and A. hardyi as parents, Phytotaxa 464 (3), pp. 252-256 : 253-255

Aloe × engelbrechtii Gideon F.Sm. & Figueiredo , nothosp. nov.

Type: — SOUTH AFRICA. Gauteng province.—2528 (Pretoria): Pretoria , (– CA), ex hort., 04 July 2020, G. F. Smith 1110 (holotype PRU) .

Parentage: — Aloe arborescens Miller (1768 : no. 3 on first page headed “ALO ALO”) × Aloe hardyi Glen (1987 : plate 1942)

Diagnosis: —Plants of A. × engelbrechtii are small to medium-sized and, in size, closer to A. hardyi than to A. arborescens . The stems of A. × engelbrechtii are horizontally growing to pendent, so more closely approximating those of A. hardyi , while A. arborescens has stems that are typically erect to leaning. In stem length, too, A. × engelbrechtii is closer to A. hardyi in that its stems are rather short to medium-long, unlike those of A. arborescens that are generally stouter and can grow to a greater length. The leaves of A. × engelbrechtii are down-curved to slightly and haphazardly horizontally spreading; those of A. hardyi are often fully down-curved, while those of A. arborescens are horizontally spreading to obliquely down-curved. In A. × engelbrechtii the terminal leaf portions sometimes dry early, as is found in A. hardyi , while in the case of A. arborescens this feature is much rarer. As in the case of both parents, the leaves of A. × engelbrechtii are unspotted. As found in A. hardyi , the inflorescences of A. × engelbrechtii are rather short, laxly- to subdensely-flowered racemes, and much more rarely paniculate. In the case of A. arborescens the racemes are larger, often densely flowered, and distinctly conical. The buds of A. × engelbrechtii are reddish orange and dark green-tipped; the open flowers are uniformly reddish orange, pencil-shaped, and pendulous. Aloe × engelbrechtii shares these character states with its parents, A. arborescens and A. hardyi .

Description: —Plants small to medium-sized, horizontally-growing to growing vertically downwards, branched from the base. Stem 40–50 cm long, clothed in somewhat twisted, variously down-curved, dry leaves that are eventually shed. Leaves rosulate, lanceolate, sickle-shaped, down-curved to slightly and haphazardly horizontally spreading, light green to glaucous, 30–40 cm long, 3.5–4.0 cm wide at the base, terminal ¼ dry, twisted; both surfaces smooth, unspotted; margins concolorous, armed with stiff but harmless, ivory-coloured to concolorous teeth, 3–5 mm long, 9–18 mm apart, straight or slightly to distinctly curved towards leaf apex; leaf exudate translucent. Inflorescence a raceme, rarely paniculate, one produced per flowering season, 25–30 cm tall, gracefully curved upwards. Peduncle thin, with several scattered, sterile bracts lower down; bracts ± 12–15 mm long, drying rapidly, light brown, elongated-triangular. Racemes conical, 10–150 cm long, ± 8–9 cm wide where flowers are at anthesis, usually subdensely-flowered; buds erect to horizontally spreading just before anthesis, flowers pendulous at anthesis. Floral bracts elongated-triangular, strongly clasping the pedicel and base of flower, more elongated than sterile bracts. Flowers pedicellate, copiously nectariferous; pedicels 18–25 mm long, light green; perianth buds reddish orange and dark green-tipped; open flowers uniformly reddish orange, tips of perianth segments dark green, ± 35–40 mm long, ± 4–6 mm across ovary, very slightly widening above ovary, ± straight, pencil-shaped, very slightly narrowing towards the mouth, the middle and apical ½ cylindrical, tips spreading to very slightly flared, outer segments free for their entire lengths; stamens with filiform-flattened filaments, included and exserted part uniformly light yellow, exserted for up to 3 mm; anthers orange; ovary 5–7 mm long, 2–3 mm in diameter, light green; style well-exserted, included and exserted parts uniformly light yellow; stigma small, hardly capitate, yellowish white. Fruit not seen. Seed not seen. Chromosome number: unknown.

Eponymy: — Aloe × engelbrechtii is named for Mr Barend “Ben” Engelbrecht (born Germiston, Gauteng province, South Africa, 17 May 1950 –) ( Fig. 3 ). Ben qualified with a Diploma in Forestry (1975, Saasveld), National Diplomas in Horticulture (1981) and Parks and Recreation Management (1983, both Cape Technicon), and in Management Development (2000, Stellenbosch University). He initially held several positions in Forestry: at Storms River (1971), Saasveld (1972– 1973), Mac-Mac, Wilgeboom, Mariepskop, and Isidenge, then as Training Forester at Concordia and Woodville, and later as Labour and Training Officer of the then Northern Transvaal Region (Louis Trichardt). This was followed by positions in Parks and Forests and horticulture at Wemmershoek Dam (Paarl), Kloofnek (Cape Town), and Nuweland (Cape Town). Thereafter Ben joined the National Botanical Institute, one of the forerunners of the South African National Biodiversity Institute (SANBI), and held positions as Estate Manager in the Kirstenbosch National Botanical Garden and as Curator of, first, the Karoo [later the Karoo Desert] and then the Free State National Botanical Gardens, in both instances focussing on the development of these facilities. Ben then transferred to the Human Resources Division of SANBI and retired as Deputy Director: Human Resources in October 2012.

Figures

FIGURE 3. Ben Engelbrecht who is commemorated in Aloe ×engelbrechtii. Photograph taken on 26 November 2019 by Gideon F. Smith.