Aloe candelabrum, A.Berger

Smith, Gideon F., Klopper, Ronell R., Crouch, Neil R. & Figueiredo, Estrela, 2016, Reinstatement of Aloe candelabrum A. Berger (Asphodelaceae: Alooideae), a tree-like aloe of KwaZulu-Natal province, South Africa, Bradleya 34, pp. 59-69 : 59-65

Differences between mature specimens of Aloe candelabrum and Aloe ferox

Aloe candelabrum is characterised by its tall [2–4(–8)m high], erect, unbranched stem covered in a ‘beard’ of persistent, dried leaves, with a terminal rosette of long (ca. 100 × 15cm), spreading to often recurved, deeply channelled leaves ( Figure 1 ) that sometimes bear a few scattered spines on the lower surface, especially at the tip of the keel. The reddish to reddish-brown marginal teeth are pungent and ca. 3mm long ( Figure 2 ). The candelabrum-like inflorescence is 5- to 12- branched with erect, very dense, cylindrical, slightly acuminate racemes 50–80cm long, with the terminal raceme sometimes slightly longer than the lateral ones ( Figures 1 and 3 ). Flowers are scarlet, sometimes rose-pink, orange-red ( Figure 4 ) to orange ( Figure 5 ), and ca. 32mm long, always with white inner segment tips ( Figures 4 and 5 ) ( Table 1 ). Very rarely they are white ( Figure 6 ).

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Figure 8. Pungent reddish-brown spines along the leaf margins of Aloe ferox, Nieu Bethesda , Eastern Cape province. Photograph: Neil R. Crouch.

In the eastern parts of the Eastern Cape province and southern parts of KwaZulu-Natal, and from the Mtamvuna valley through to Ixopo, Aloe candelabrum and A. ferox seemingly intergrade. This is evidenced by some populations having plants with more erect leaves ( Figures 12 and 13) or slightly recurved ones ( Figure 14 ), and A. ferox -like spines along both leaf margins and undersides ( Figure 15 ). We speculate that it is on this basis that Jeppe (1969) considered A. ferox to occur from south of Ixopo. However, within this southern KwaZulu-Natal region white perianth apices are always evident, an observation also noted by Viljoen et al. (1996). Where the distribution ranges of related Aloe species meet, such intergradations are not uncommon, as noted for A. spectabilis ( Klopper & Smith, 2010).

In Aloe candelabrum the teeth on the leamargins are quite short and stout, about 3mm long, and spaced 15–20mm apart ( Figure 2 ), while in A. ferox the teeth are generally larger and more prominent, up 6mm long, and often more closely spaced at 10–20mm distant ( Figure 8 ).

Geographical distribution ranges of Aloe candelabrum and Aloe ferox Both species are confined to either southern Africa ( Aloe ferox ) or South Africa ( Aloe candelabrum ), with Aloe ferox predominating in the Western and Eastern Cape provinces of South Africa, extending northwestwards into the Free State province, as well as southern Lesotho. It does not occur in KwaZulu-Natal, and no specimens are known from the Northern Cape province, even though it occurs close by the juncture of that territory with both the Western and Eastern Cape provinces ( Figure 16 ).

Aloe candelabrum , on the other hand, is confined to southeast-central KwaZulu-Natal, South Africa, where it is more or less restricted to the northern and western aspects of valleys of all river systems from the Mtamvuna northwards to the Mngeni. This species in its typical form is a particularly prominent component of the landscape of the Mkomazi River system, and those to the north. The entire distribution range of Aloe candelabrum falls within the Maputoland-Pondoland Region of Endemism on the eastern seaboard of South Africa (Van Wyk & Smith, 2001). Along the actual KwaZulu-Natal coastline, Aloe candelabrum is replaced by Aloe thraskii Baker, which is also a robust, tall-stemmed species, albeit with shorter, more dense inflorescences. Within the range of A. ferox in the Eastern Cape, from north of Port Elizabeth to near Humansdorp, Aloe africana Mill. occupies a comparable niche in the littoral zone. However, unlike A. thraskii , A. africana also occurs at locations in the interior (see maps in Van Wyk & Smith, 2014: 52 [ A. africana ] and 80 [ A. thraskii ]).

A single specimen known to us (A.T.D. Abbott 7003 [NH]) locates a tree-like aloe with white tepal tips in the extreme north of the Eastern Cape province, near Mbizana, on a ridge above the Mtamvuna River at an altitude of 640m. The colony from which the specimen (comprising a raceme branch only) was gathered in 1996 was recorded as a mixture of orange, red and whiteflowered plants. As the original collecting label indicates that the flowers were from a white-flowering plant, we are unable to determine whether this material represents A. ferox or A. candelabrum . Until the colony is revisited and assessed, we deem A. candelabrum to be documented only from KwaZulu-Natal province; it is though highly likely to occur to the immediate south in Eastern Cape province. Albinistic blooms such as those noted at Mbizana are seldom reported for A. candelabrum , but have been observed both at Izingolweni and Ashburton ( Figures 6 and 17 ), in the south and the northwest of its range, respectively.

Figures

Figure 1. The large rosettes of Aloe candelabrum are carried atop robust stems that are clothed in the remains of dry leaves, Ashburton, KwaZulu-Natal province. Photograph: Neil R. Crouch.

Figure 2. The channelled leaves of Aloe candelabrum have margins armed with reddish-brown teeth. Photograph: Neil R. Crouch

Figure 4. Orange-red flowers of Aloe candelabrum, with prominent white flared tepal apices, Ashburton, KwaZulu-Natal province. Photograph: Neil R. Crouch.

Figure 5. Another Ashburton flower form of Aloe candelabrum is orange, with scarlet and rose-pink forms also present. The flared white inner tepal apices are conspicuous. Photograph: Neil R. Crouch.

Figure 6. Rare white flowers of Aloe cande- labrum, Ashburton, KwaZulu-Natal province. Photograph: Neil R. Crouch.

Figure 7. Colony of Aloe ferox plants, Jansenville, Eastern Cape province. Robust stems clothed in persistent, dried leaves present rosettes of erect to spreading leaves, rarely recurved. Photograph: Neil R. Crouch.

Figure 8. Pungent reddish-brown spines along the leaf margins of Aloe ferox, Nieu Bethesda, Eastern Cape province. Photograph: Neil R. Crouch.

Figure 9. Population of Aloe ferox south of Swellendam, Western Cape province. Both leaf surfaces are either smooth or with irregularly scattered, pungent spines, and the lower surface has a few spines in the median line near the apex. Photograph: Estrela Figueiredo.

Figure 10. Bright orange flower form of Aloe ferox, also with prominent, dark inner tepal apices that typically do not flare, Jansenville, Eastern Cape province. Across its range, perianth colour varies from scarlet through orange and yellow to white. Photograph: Neil R. Crouch.

Figure 11. Reddish-orange flowers of Aloe ferox, with inner tepal apices that seemingly clasp the extended filaments, Queenstown, Eastern Cape province. The tips of the inner tepals of Aloe ferox are brown to deep brown, or at least more in- tensely coloured than the rest of the corolla. Photograph: Neil R. Crouch.

Figure 12. Tall specimens of Aloe candelabrum at Izingolweni, southern KwaZulu-Natal province. These plants share various characteristics with A. ferox, including erect to spreading leaf orientation. Photograph: Geoff Nichols.

Figure 14. Some recurved leaves are shown in this group of Aloe candelabrum plants at Izingolweni, southern KwaZulu-Natal. Photograph: Geoff Nichols.

Figure 15. The arrangement of leaf prickles on this Aloe candelabrum plant at Izingolweni in southern KwaZulu-Natal is comparable to that observed in some Aloe ferox specimens from the Eastern Cape province. Photograph: Geoff Nichols.

Figure 16. Known geographical distribution range of Aloe candelabrum (orange shading) and Aloe ferox (red shading) in southern Africa (South Africa and Lesotho).

Figure 17. A white-flowering plant of Aloe candelabrum at Izingolweni in southern KwaZulu- Natal. Photograph: Geoff Nichols.

Figure 8. Pungent reddish-brown spines along the leaf margins of Aloe ferox, Nieu Bethesda , Eastern Cape province. Photograph: Neil R. Crouch.

Tables

Table 1. Differences between mature specimens of Aloe candelabrum and Aloe ferox.

#	Character	Aloe candelabrum	Aloe ferox
1	Rosette	Very large (c. 2m diam.)	Medium-sized to large (<2m diam.)
2	Leaf length	c. 1m	<1m rarely to 1m
3	Leaf curvature / disposition	Spreading to often gracefully re- curved, occasionally erect	Erect to somewhat spreading, seldom recurved
4	Inflorescence structure	Up to 12 raceme branches	Not more than 8 raceme branches
5	Tepal apices colour	Lighter, white-tipped. Outer slightly darker than inner	Darker, brown-tipped. Outer always lighter than inner
6	Inner tepal apices disposition	Flared, filaments free	Not flared, often clasp filaments
7	Distribution range	East-central KwaZulu-Natal province of South Africa	Western Cape, Eastern Cape, and Free State provinces of South Africa; Lesotho

Table 1. Differences between mature specimens of Aloe candelabrum and Aloe ferox .