Aloe × nobilis Haworth (1812: 78)

Smith, Gideon F., Figueiredo, Estrela, Verloove, Filip, Klopper, Ronell R. & Silva, Vasco, 2023, An annotated catalogue of Aloe and Aloiampelos (Asphodelaceae subfam. Alooideae) naturalised and escaped in continental Portugal, Phytotaxa 629 (1), pp. 35-52 : 41-43

3. Aloe × nobilis Haworth (1812: 78) pro sp. ( Fig. 4 ).

Locally used synonyms:—None recorded.

Common name(s):— Portuguese: None recorded. English: golden tooth aloe.

Description:—Plants acaulescent or with short stem up to 0.2 m long; rosettes profusely suckering from the base to form large , dense, mound-shaped clusters. Leaves generally densely rosulate, erectly spreading to slightly in- or recurved, 10–15 × (2–) 4–6 cm, lanceolate-triangular to lanceolate-deltoid, dark green, white maculations generally lacking, both ad- and especially abaxial surfaces sometimes with scattered teeth on white base; margin concolorous; marginal teeth ± 10 mm apart, (3–) 5 mm long, firm, white to slightly yellowish. Inflorescence 0.5–0.8 m high, erect, sometimes 1-branched. Racemes 10–20(–30) cm long, cylindrical-conical, subdense. Floral bracts ± 15–18 × (5–) 6 mm. Pedicels 25–30 mm long. Flowers: perianth 35–40 mm long, 6–8 mm across ovary, of ± even diameter throughout, very slightly narrowing towards mouth, ± straight, cylindric, bright orangey red; outer segments free for 10–12 mm; stamens exserted 2–4 mm; style exserted to 5 mm. Capsules not seen.

Flowering time:—(May–)June–July(–September).

Habitat:—Coastal dunes.

First mention of the species as naturalised in Portugal:—Not previously recorded.

Localities recorded:—Ag (Praia do Amado, near Portimão).

Country / region of origin:—A hybrid that very likely originated in Europe.

Secondary distribution range:— Aloe × nobilis is very rarely reported as an escape, doubtlessly owing to it being confused with A. mitriformis Miller (1768 : first page headed “ALO-ALO”, species # 1), one of its alleged parents. It can be reasonably assumed that at least some of the naturalised populations of the latter in fact refer to A. × nobilis . Guillot Ortiz & Laguna Lumbreras (2019) published the first Spanish (and European) record of A. × nobilis in the wild. Its status in Spain is uncertain; however, in Catalonia it is considered to be merely ephemeral ( Aymerich & Sáez 2019).

Status in Portugal:—Naturalised.

References:— Smith & Figueiredo (2015a: 156, 2015b: 75).

Notes:— Aloe × nobilis is most often misidentified as A. perfoliata Linnaeus (1753: 319–320) . The name A. perfoliata is variously interpreted, with, most recently, the proposal having been made that the name applies to what has been known consistently as A. microstigma Salm-Reifferscheid-Dyck (1854: 6, § 26, f. 4) ( Mottram 2013; see also Klopper et al. 2016). However, the true identity of A. perfoliata remains uncertain ( Klopper et al. 2016).

Reynolds (1950: 385) and Grace et al. (2011: 110) suggest A. arborescens and A. mitriformis as possible parents of A. × nobilis . Based on its comparatively small stature, Smith & Figueiredo (2015a: 156, 2015b: 75) speculate that A. brevifolia Miller (1768 : first erratum page) and A. mitriformis could be the parents of this hybrid. However, the leaves of the latter two species, especially those of A. brevifolia , are generally variously glaucous green, while those of Aloe × nobilis are a deep green colour ( Fig. 4A, C–D ). The subdense, cylindrical-conical inflorescences of A. × nobilis are reminiscent of those of A. brevifolia ( Fig. 4B ). All three putative parents have been in cultivation in Europe for several centuries ( Cullen 1986: 159 [ A. brevifolia ], 160 [ A. mitriformis , in error as A. perfoliata ], 161 [ A. arborescens ]). Aloe × nobilis itself was not mentioned in Webb (1980) nor in Cullen (1986) though. Note that reference to A. perfoliata in Webb (1980: 20 [species # 6]) is in fact to A. mitriformis , as evidenced by, inter alia, mention of “Racemes […] subcapitate”.

Aloe × nobilis is clearly an old hybrid that has remained well-known in European horticulture. In the late-1700s, it was for example illustrated by the Bauer brothers for Father Boccius’s Liber regni vegetabilis, also known as Codex Liechtenstein, some years before it was formally named by Adrian H. Haworth in 1812 ( Mabberley 2017: 3). This nothospecies has remained popular in outdoor cultivation in parts of southern Europe with a mild-climate ( Fig. 4C ), but also thrives under glass in more severe climates.

Figures

FIGURE 4. Aloe ×nobilis in Portugal. A. The leaves are dark green, often more so when growing in shaded positions, as here. Leaf margins are concolorous and carry rather widely spaced, firm, white to slightly yellowish teeth, which gave rise to the English common name, golden tooth aloe. In full sun the leaves are usually distinctly reddish-infused. B. The cylindrical-conical, subdense racemes are up to 30 cm long. Photograph taken on 29 June 2012 of a plant cultivated in central Portugal. C. Aloe ×nobilis (in the container on the right) is commonly cultivated in Portugal, here in a domestic garden near the town of Serra de Santo António in the centre of the country. A ×Gasteraloe Guillaumin (1931: 339) hybrid [Aloe × Gasteria Duval (1809: 6)] grows in the container on the left. Photograph taken on 1 January 2013. D. Naturalised in dune vegetation at Praia do Amado, near Portimão, Algarve. Photograph taken on 17 September 2013. All photographs by Gideon F. Smith.