Aloe vera ( Linnaeus 1753: 320 ) Burman filius (1768: 83)

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 : 43

4. Aloe vera ( Linnaeus 1753: 320) Burman filius (1768: 83) ( Fig. 5 ).

Locally used synonyms:— Aloe barbadensis Miller (1768 : first page headed “ALO-ALO”, species # 2).

Common name(s):— Portuguese: aloé, aloé-de-Barbados, azebre, azebre-vegetal, azevre, babosa, cacto-dos-aflitos, cura-câncros, erva-azebra, erva-babosa, erva-que-arde, planta-dos-milagres, planta-mistério, planta-que-cura. English: medicinal aloe ( Grace et al. 2011).

Description:—Plants acaulescent or with very short stem up to 0.3 m; suckering at base to form dense groups. Leaves densely rosulate, erectly spreading, generally straight, up to 30–60 × 5–8 cm, lanceolate-attenuate, dull greyish green, sometimes with scattered, dull, irregularly shaped, whitish maculations when young, maculations generally lacking at maturity; margin concolorous to pinkish; marginal teeth 1–2 mm long, 10–15(–20) mm apart, harmless, firm, pale to whitish; exudate yellow. Inflorescence 0.5–1.0 m high, erect, sometimes 1- or 2-branched. Racemes 30–50 cm long, cylindrical acuminate, dense. Floral bracts ± 10 × 5–7 mm. Pedicels ± 5 mm long. Flowers: slightly to distinctly ventricose; perianth 25–30 mm long, up to 8 mm across ovary, narrowing towards mouth, slightly upcurved, yellow, green-tipped and -lined in bud; outer segments free for 15–18 mm; stamens exserted 3–5 mm; style exserted to 5 mm. Capsule 1.5–2.0 cm long, oblong.

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

Habitat:—Maritime rocks ( Coutinho 1939: 151); escarpments and sea cliffs ( Franco & Afonso 1994: 45).

First mention of the species as naturalised in Portugal:—1896 ( Coutinho 1896: 78, as “ Aloe vulgaris ”). Coutinho (1896) based the record on material collected between Sines and Vila Nova de Milfontes (BAl) by Friedrich Welwitsch who had an interest in succulents cultivated in Portugal ( Figueiredo et al. 2018).

Localities recorded:— Coutinho (1939: 151) recorded it from the coast of the same province, i.e., BAl. Later, Franco & Afonso (1994: 46) recorded it as rare in “SW mer.”, i.e. the southern west coast (BAl). Almeida (2012: 209) and Güemes (2013: 312) also recorded it for BAl only. Mabberley & Placito (1993: 47) further recorded it as naturalised at Praia D. Ana, Lagos (Ag).

Country / region of origin:—Uncertain (see Newton 2020: 675–676 for a discussion).

Secondary distribution range:— Aloe vera is widely naturalised, especially in areas with a Mediterranean climate. It was first indicated as escaped on the Iberian Peninsula by Colmeiro (1874: 1) and its naturalisation has been reported from many countries in the Mediterranean area, for example Spain (e.g. Guillot Ortiz et al. 2008), Gibraltar ( Lamb 1996, as A. barbadensis ), Italy (naturalised only in the southernmost areas, casual elsewhere; Galasso et al. 2018, Musarella et al. 2020), Malta ( Mifsud 2022), and Greece ( Arianoutsou et al. 2010). It is furthermore naturalised in the Atlantic Islands (Canary Islands, Madeira) and most of North Africa ( Morocco, Tunisia, Algeria, and Libya) ( Dobignard & Chatelain 2010). It is also naturalised in, among others, India, Indonesia, Mexico, and the Caribbean. In some areas of its secondary range, A. vera is considered to be an invasive species.

Status in Portugal:—Naturalised.

References:— Coutinho (1939), Webb (1980), Franco & Afonso (1994), Almeida & Freitas (2006), Almeida (2012), Güemes (2013).

Notes:—Globally, A. vera is the most important medicinal aloe and it is widely cultivated for various leaf components (see for example Reynolds 2004 and Grace et al. 2015) ( Fig. 5A–B ). It is therefore unsurprising that it has become naturalised in various parts of the world.

In Portugal, A. vera is essentially a summer-flowering species with a relevant, at the time, contemporary mention of its cultivation given by Gomes & Beirão (1852). Some variation has been observed in the timing of flowering, especially in other parts of the world, but plants generally do not flower in winter. The flowers of A. vera are yellow ( Fig. 5C–D ), but also in this case, some variation is evident, with orangey red flowers having been recorded in some variants of the species. Aloe indica Royle (1839: 390) has been interpreted as such a red-flowered variant of A. vera (see Reynolds 1966: 145, 150, 524). However, non-yellow-flowering material of A. vera is yet to be formally recorded as naturalised in Portugal.

Figures

FIGURE 5. Aloe vera in Portugal. A. Potted specimens of A. vera (plant on the left) and A. ×nobilis (plant on the right) grown on a windowsill in Caldas da Rainha, Estremadura. Especially A. vera is often kept near a kitchen with its leaf juices used to treat minor burns and skin abrasions. Photograph taken on 11 September 2011. B. Grown in a large plant container on the stoep of a house near the town centre in Golega, in the centre of the country. Photograph taken on 17 January 2018. C. A branched inflorescence. D. Close-up of flowers and buds. All photographs by Gideon F. Smith.