General Info – summary

This adaptable Tree trunk is up to 5m high.  Succulent Leaves have an amplexicaul base and spines occur on margins and possibly the blade.  Shrunken old leaves remain.  Regular Flowers are in up to 12 erect racemes.  6 tepals occur outside the 6 exserted stamens.  The pistil has a superior ovary and a single exserted style.  Fruit: a trilocular apically truncated capsule with irregularly angled & slightly winged seeds.

Description

Aloe ferox

Previous Names: Aloe candelabrum, Aloe galpinii, Aloe perfoliate, Aloe pseudo-ferox, Aloe subferox, Aloe supralaevis, Pachidendron ferox, Pachidendron pseudo-ferox, Pachidendron supralaeve, Aloe perfoliate.

SA Tree No. 29.2.

Common names:  (Afr) Aalwyn, Bergaalwee, Bergaalwyn, Bitteraalwyn, Kanniedood, Kraalalwee, Kraalalwyn, Makalwee, Opregte Aalwyn, Regte Aalwee, Regte Aalwyn, Swellendam-aalwyn, Swellendamsaalwee, Mak-aalwyn, Tapaalwyn, Tapalwee, Tap-aalwyn, Tapalwyn.  (Eng) Bitter Aloe, Cultivated Aloe, Red Aloe,  Tap Aloe, Uganda Aloes.  (isiXhosa) Ikhala, Ingcelwane.  (isiZulu) Inhlaba, Umhlaba.   (Setswana) Hlaba, Lekhala La Quthing Ikhala, Umhlaba.  (siSwati) imBovane.

Family: Asphodelaceae (Aloe Family).  Presumably derived from Asphodel Meadows, which is a section of the Ancient Greek underworld where indifferent and ordinary souls were sent to live after death.  The family has about 40 genera and 900 species.  There are 10 genera in the South Africa.  This is a small but wide spread, mainly African family of perennial plants.  All have Anthraquinones (an aromatic, organic compound, which is the main active constituents of herbs – often used to relieve constipation and may possess antifungal and antiviral activities.  They are also widely used in dyes).  When present, the Stems are fibrous and woody.  The fleshy Leaves often have spines either on the margins or on the blades.  The outer 2 flower whorls (the Perianth) lack the classic distinction between calyx and corolla and the lobes are called Tepals.  These 2 whorls each have 3 tepals.  Flowers are usually borne on a leafless stalk arising from the rosette of leaves.  Individual flowers are regular.  The 6 Stamens are inserted in 2 whorls of 3, below the superior 3 locular Ovary.  Fruit is usually a dry Capsule.  Genera with trees on this website include Aloe, Aloidendron and Kumara.

The name Aloidendron or ‘tree aloe’ dates to 2013 and is thanks to molecular studies that are rather shaking up phylogenies and thus classifications.  The rambling aloes have also been put in their own genus: Aloiampelos. About 20 of these are considered to be trees.

Name derivation: Aloe – dried juice from aloe leaves (Greek origin).  ferox – ferocious: referring to the spiny leaves.  There are about 500 species within the Aloe genus and at least 150 are indigenous in South Africa.

Conservation: National Status: L C. Least Concern.  Assessed: 2018 (D. Raimondo, J.H. Vlok, B.E. van Wyk, E.J. van Jaarsveld and H. Mtshali).  However, the exploitation of leaf harvesting may need attention in the future.

Tree

This succulent, perennial Tree may reach 5m high.  The thickset, usually singular Stem or trunk is main axis of the plant, the leaf and flower bearing as distinguished from the root-bearing axis.  In Aloe ferox the plant stem becomes densely bearded with shrunken, down hanging, old dry leaves that remain on the tree (photo 73).

Leaves

Each succulent fleshy Leaf is up to 1m long and 16cm wide at the base.  They occur at the end of the stem in a dense rosette (leaf arrangement radiating, in this instance, from a crown – photo 432).  Short, reddish, stout Spines may appear on the Margin and here they may be dentate (with sharp, spreading, rather coarse teeth that are perpendicular to the margin).  They start of at right angles to the margin and may have the end pointing slightly toward the leaf apex (photo 80).  Spines may occur on the Blade (similar to Aloe marlothii).  The broad Base of each leaf is decurrent (extends down and is attached to the trunk).  The leaf gradually decreases in width ending with a narrow Apex (photo 432).  Young leaves point upwards.  The slightly recurved mature leaves are bluish green and often tinged with yellow or red.  Unlike Aloidendron barberae (was Aloe barberae), the old grey, dried and shrunken leaves remain hanging and extend more than half way down the tall usually single trunk.

Flowers

The orange, scarlet or red (photo 76) and, less commonly, white Flowers are produced in a single branched Inflorescence containing up to 12 Racemes (a simple, unbranched, indeterminate inflorescence with pedicellate – stalked flowers along the axis that open in succession towards the apex).  Each raceme produces erect, relatively wide, cylindrical structures up to 0,9m high, on which the stalked, densely packed, smallish individual flowers rest.  Each flower has 6 Tepals (sepals and petals are not clearly defined and collectively make up the Perianth) in 2 rows of 3 each.  The apices of the inner 3 are brown, black (photo 640) or white.  The outer whorl of 3 is usually darker.  The 6 yellow/orange Stamens are in 2 whorls of 3 each (photo 640).  They are longer than the perianth lobes (photo 421 & 637).  On photo 637, the relatively young, orange Anthers are visible.  Within the stamens is a single Pistil (a unit of the Gynoecium, the female element of the flower, composed of the Ovary, Style and Stigma – photo 640).  The superior Ovary is trilocular (with 3 compartments) and there is a single filiform (thread or filament like) Style.  The small terminal Stigma is capitate (formed like a head) and well exserted.  Flowering near the Cape and close to the coast occurs from May to June whereas Inland it occurs from Jul-Sep).  This difference is probable influenced by temperature.  Plants on the north facing slopes open first.

Fruit

After pollination, the tepals shrink and eventually fall, exposing the old stamens (photo 497).  As the capsule develops, the stamens also fall. The Fruit is a 3-segmented Capsule (a dry fruit resulting from the maturing of a compound ovary, which usually opens at maturity by one or more lines of dehiscence).  This capsule is apically truncated (appearing as if cut off at the end – photo 497).  The irregularly angled and laterally compressed Seeds are obscurely winged.

Distribution & Ecology

This aloe is Endemic (Endemism is the ecological state of a species being unique to a defined geographic location).  It is widely distributed only in southern Africa – including fynbos (this is a belt of natural shrubland – dense thickets of evergreen shrubs and small trees in the winter rainfall area within the distinctive vegetation of the Western Cape).  They also occur in the Western Cape, Eastern Cape, southeast Free State, southern KwaZulu-Natal and southern Lesotho – from sea level to moderate altitudes (usually less than 700m).  When flowering they are most dramatic in open spaces e.g., in the Karoo. Rainfall requirements are from 200 to 750mm pa.  These trees survive temperatures from between -5 and 45 degrees C.  This aloe is a Pioneer species in over utilised soils.  Animals eat leaves in dry times.  The Flowers are rich in nectar (10 flowers produce up to 1 cubic cm), and this attracts Birds including sunbirds, black-headed oriole (Oriolus larvatus), weavers, starlings and long tailed, speckled mousebirds (Colius striatus).  This bird is common from the Cape to Eritrea.  White-eyes and other birds, with shorter beaks, cannot reach the nectar directly and reach it by burrowing through the base of the flowers.  The nectar also attracts monkeys and baboons as well as insects.  These insects attract more birds.  The multi-branched flower structure and the much further north habitat of Aloe excelsa is the best way of distinguishing it from Aloe ferox.

Ethnobotany

Children also seek after the Flower Nectar.  If consumed in large quantities it may cause partial paralysis.  Leaf Sap contains the drug “Cape Aloes”, (which contains Aloin, which is a very bitter yellow-brown coloured compound).  Aloin is an effective laxative – but can have side effects.  Leaves have been used to make a good jam.  The leaves have an important commercial value as a medicinal plant.  In times of need, farmers feed leaves to their cattle.  Bushman paintings in caves were the first known illustrations of this aloe.  Shrunken, dry old leaves are good fire starters – burning for a short time with an intense heat.  Burning the old leaves also acts as an insect repellent.  Crushed dry leaves are used to make snuff.  This plant can survive some frost.  As early as 1700, this aloe was planted in European gardens.  Hybrids do occur – including between this plant and Aloe arborescens.

References

Boon, R. 2010. Pooley’s Trees of eastern South Africa. Flora and Fauna Publications Trust, Durban.

Coates Palgrave, M. 2002. Keith Coates Palgrave Trees of Southern Africa, edn 3. Struik, Cape Town.

Ginn, P.J. McIlleron, W.G. Milstein, S. 1989. The Complete Book of Southern African Birds. Struik Publishers (PTY) LTD. Third impression 1991.

Lawrence, G. H. M, 1951. Taxonomy of Vascular Plants, The Macmillan Company, New York. Tenth Printing 1965.

Palmer, E. & Pitman, N. 1972. Trees of southern Africa, Balkema, Amsterdam, Cape Town.

Raimondo, D., Vlok, J.H., van Wyk, B.E., van Jaarsveld, E.J. & Mtshali, H. 2018. Aloe ferox Mill. National Assessment: Red List of South African Plants version 2020.1. Accessed on 2022/12/09.

van Wyk, B. & van Wyk, P. 1997 Field guide to Trees of Southern Africa, Struik, Cape Town.

 

https://en.wikipedia.org/wiki/Aloe_ferox

http://operationwildflower.org.za/index.php?option=com_content&view=article&id=107:aloe-ferox&catid=19&Itemid=29

http://www.plantzafrica.com/plantab/aloeferox.htm

https://en.wikipedia.org/wiki/Aloin