Aloe ser. Macrifoliae

The Climbing Aloes
Aloe tenuior, a member of the Macrifoliae series.
Scientific classification
Kingdom: Plantae
(unranked): Angiosperms
(unranked): Monocots
Order: Asparagales
Family: Xanthorrhoeaceae
Subfamily: Asphodeloideae
Genus: Aloe
Series: Aloe ser. Macrifoliae
Haworth
Species

See text

Aloe ser. Macrifoliae (the "Climbing Aloes") is a taxonomic series within the genus Aloe, comprising seven closely related species of Southern African climbing aloe. These aloes are typically multi-branched climbing or sprawling shrubs, with long spindly stems and a large woody base on the ground. These characteristics, as well as their soft, narrow, triangular leaves whose lower part ensheathes the stem, make these Aloes easy to distinguish.

This group of aloes is centered in the Eastern Cape, South Africa where they are also particularly common. A few rare species also occur in isolated pockets further west in the fynbos vegetation of the Western Cape.

Taxa

The most common species in this group is probably Aloe ciliaris which is relatively widespread in South Africa. It seems to have developed from the smaller, rarer, finely leaved Aloe tidmarshi (now re-classified as a subspecies, Aloe ciliaris tidmarshi) and to have spread out across the country relatively recently.
Its relatives, moving westwards along the South African coast, are: Aloe tenuior of Kwazulu-Natal and the Eastern Cape, Aloe striatula of the higher mountain ranges bordering the Karoo, and Aloe gracilis of the area around Port Elizabeth (where the Eastern Cape thickets fade into the Western Cape fynbos vegetation).

Further west, the Fynbos vegetation of the neighbouring Western Cape is subject to frequent fires, making it relatively inhospitable for Aloes. Nevertheless, several rare relict Macrifoliae Aloe species survive in tiny isolated pockets within the Fynbos biome, such as Aloe decumbens, Aloe juddii and Aloe commixta.[1]

The unusual and endangered Pearson's Aloe (Aloe pearsonii) of Namibia is considered by many botanists to be an outlying member of this series. However more recent chemical analysis indicates that it is actually closer to the "Creeping Aloes" (Mitriformes), but is most likely a "missing-link" intermediate between the two groups. [2]

Regional Adaptations

The different species of this series show clear and distinct adaptations to their different natural habitats. The climbing aloe species that are indigenous to regions with tall, thicket vegetation are tall and erect - often with hooked, recurved leaves that allow the aloes to anchor their branches and climb up through trees and thickets. In contrast, the species from drier regions with low, sparse, fynbos vegetation tend to be more "decumbent", rambling along the ground - with no need for their leaves to be recurved. [3]

Aloe ciliaris flowers

Species and subspecies

Eastern Cape

Aloe commixta is restricted to the Cape Peninsula.

Western Cape

Aloe commixta. The orange variety.

Cultivation

Due to their hardiness and the wide range of flower colours, these slender aloes have become popular ornamental plants in South African gardens. The commoner species (such as the more widespread aloes of the Eastern Cape) are increasingly grown in gardens overseas too. Like most aloes, Climbing Aloes require a sunny, well-drained position and are particularly suitable for rockeries. The taller, climbing species are commonly planted along fences and boundaries where they grow up through the surrounding foliage. The lower, rambling species however, are better suited for rockeries, slopes or terraces, which they will naturally cascade down over.

The colour of the flowers varies from bright yellow (Aloe commixta and Aloe tenuior) to orange (Aloe striatula and Aloe commixta) to red, pink or even scarlet (Aloe ciliaris, Aloe juddii and Aloe gracilis). There can also be significant colour variation among different populations within each individual species.

They can easily be propagated by taking cuttings (truncheons), as well as by seed. These aloes generally have both male and female flowers on each plant, but an individual plant is usually not self-fertile by itself. However, some of the different Macrifoliae aloe species are also inter-fertile, and can thus form hybrids.

References

  1. ↑ Court D: Succulent Flora of Southern Africa. Cape Town: Struik Nature. 2010. ISBN 978-1-77007-587-0
  2. ↑ http://www.plantzafrica.com/plantab/aloepearson.htm
  3. ↑ Reynolds, G: The Aloes of South Africa. Cape Town: A.A.Balkema 1969.