Aloe × spinosissima

Smith, Gideon F., 2019, The taxonomy of aloe xspinosissima hort. ex a. berger (asphodelaceae), a popular hybrid aloe from mediterranean Europe, Bradleya 37, pp. 26-30 : 26-29

Identity of Aloe × spinosissima Hort. ex A.Berger

The earliest reference that could be traced to the name Aloe × spinosissima is where Alwin Berger (28 August 1871 [Möschlitz, Germany]– 20 April 1931 [Stuttgart, Germany]) described a hybrid aloe under this name in “§ 5 Echinatae ” ( Berger, 1908: 183) ( Figures 3 & 4 ). Three years earlier, where Berger (1905: 58) provided a preliminary outline of his proposed infrageneric classification of Aloe , he did not reference this nothospecies in § 2. Humiles, where it would have been grouped. The name was given to what Berger (1908) regarded as a hybrid between A. humilis var. echinata (Willd.) Baker and A. arborescens var. natalensis (J.M.Wood & M.S.Evans) A.Berger ( Berger, 1908: 19), while on the page where the protologue of the name appeared ( Berger, 1908: 183), he amended his view of the infraspecific classification of the A. arborescens parent to A. arborescens var. pachythyrsa A.Berger. Note though that both A. humilis and A. arborescens are nowadays treated as variable species where the recognition of infraspecific taxa is hardly warranted ( Van Wyk & Smith, 2014: 290–291; Crouch et al., 2008; Smith et al., 2008, 2012).

Natural hybrids have been recorded between Aloe humilis and A. lineata (Aiton) Haw. from near Port Elizabeth (Eastern Cape Province, South Africa), and between A. humilis and A. microstigma Salm-Dyck from near Oudtshoorn in the Klein Karoo ( Reynolds, 1950: 179).

In the case of Aloe arborescens , at least 15 natural hybrids are known ( Reynolds, 1950: 413). However, a natural hybrid between A. arborescens and A. humilis has not yet been found, even though their distribution ranges overlap in the Eastern Cape (see distribution maps in Van Wyk & Smith, 2014: 86 and 290, respectively). Aloe arborescens is known to easily cross with other species of Aloe (and species of other Alooideae genera, for that matter) that have morphologies quite distinct from its robust, shrubby growth form (cf. A. × inopinata Gideon F.Sm., N.R. Crouch & Oosth., the natural hybrid between A. arborescens and the slender aloe, A. chortolirioides A.Berger var. chortolirioides ; Smith et al., 2016).

Among aloes it is quite common to find species with widely diverging growth forms to be interfertile, with, for example, the tree-like fan aloe [ Kumara plicatilis (L.) G.D.Rowley] and low-growing, stemless partridge aloe [ Gonialoe variegata (L.) Boatwr. & J.C.Manning] also having been successfully hybridised ( Smith et al., 2018).

Nomenclature of Aloe × spinosissima

Aloe × spinosissima Hort. ex A.Berger in Pflanzenr. (Engler) Liliac.-Asphodel.-Aloin. 33: 183 (1908). Jahandiez: 570 (1933); Jacobsen: 194 (1977); Graf: 1048, 1530 (1980); Jacobsen: 197 (1986); Grace et al. 145 (2011); Smith & Figueiredo: xii, xiii, 51 (2015a).

Neotype: SOUTH AFRICA. Pretoria . Ex hort. 24 August 2018. G.F. Smith & E. Figueiredo 66 ( PRU) , designated here.

Parents:

Aloe arborescens Mill. and A. humilis (L.) Mill.

Nomenclatural notes. Herbarium Mortolense (HMGBH) has specimens of Aloe × spinosissima , but I was informed that these were not prepared during the time of Alwin Berger’s employment at the Hanbury Gardens (Alessandro Guiggi, personal communication). The specimens of A. × spinosissima held at (HMGBH) are not available for examination online. A neotype, G.F. Smith & E. Figueiredo 66, consisting of material cultivated in South Africa was therefore prepared.

Although the name Aloe × spinosissima is often noted as having been published by Jahandiez, as “Jahand. in Rev. Hort. [Paris] 23 (105 of whole series): 570 (1933)”, the name was clearly validly published 25 years earlier by Berger (1908: 183).

Description

Perennial, small to medium-sized, shrubby, rosulate, leaf succulent, up to 1m tall, usually shorter, excluding inflorescence. Stems many, sprouting from the base. Leaves lanceolate, spreading with upper ½ to ⁄3 usually gracefully recurved, 20–30cm long, glaucous to light green; adaxial surface sparingly soft-spiny, concave; abaxial surface densely soft-spiny, convex; margins adorned with white, somewhat bony but harmless teeth. Inflorescence a conical raceme, very rarely paniculate, to 50cm tall. Flowers bright orange.

Eponymy

The epithet ‘spinosissima’ means ‘very spiny’ and is derived from the Latin word ‘spinosus’ [English: spiny].

Origin

According to Jacobsen (1977: 97, 1986: 197), Aloe × spinosissima is a hybrid that was raised at La Mortola, the Hanbury Gardens (Giardini Botanici Hanbury) on the Italian Riviera. However, Berger (1908: 183) stated that “Ich erhielt die Pflanze von L. Winter in Bordighera, über ihren Ursprung ist mir nichts bekannt geworden.” [English: “I received the plant from L. Winter in Bordighera, I know nothing of its origin.”]. Following employment for the development of the Hanbury Garden, La Mortola, in northwestern Italy, from 1868 to 1875 the German horticulturalist and botanist Ludwig Jonathon Winter (9 August 1846 [Heidelberg, Germany]– 12 July 1912 [Mannheim, Germany]) was based close by in Bordighera, Italy. Alwin Berger took up the curatorship position at La Mortola in 1897, and while based there did considerable work on several succulent plant families ( Moore, 2004; Smith & Figueiredo, 2013: 94–105, 2014a).

Figures

Figure 3. Aloe ×spinosissima growing in a pedestalled, Italianate container in the Hanbury Gardens at La Mortola on the Ligurian Riviera, Italy. Photograph: Gideon F. Smith.

Figure 4. The Palazzo Orengo at the Hanbury Gardens. Alwin Berger, who described Aloe ×spinosissima, was based at the Garden at the time that he received material of this nothospecies from Ludwig Winter. Photograph: Gideon F. Smith.