Aloe meyeri
Introduction
A rare, small, cliff-dwelling aloe with drooping rosettes of greyish green leaves and simple inflorescences of small, tubular, orange-red flowers with green tips, that are pollinated by sunbirds. It is cluster-forming, with the stems becoming pendent up to 1 m long. It is only known from the Rosyntjiesberg in the Richtersveld and adjacent Namibia of the lower Orange River of the Northern Cape.
Fig. 1. Aloe meyeri in flower on the Rosyntjiesberg.
Description
Description
Aloe meyeri is a slow-growing, long-lived, perennial (from seed 5–7 years), forming loose pendulous clusters, branched from the base, with elongated stems up to 1 m long. Roots are slightly fleshy. Branches are leafy, becoming deciduous only from below or during severe drought. Leaves are crowded, ending in an apical rosette, up to 260 mm in diameter, spreading in the rainy season, inwardly curved, becoming drawn together, with a reddish colour in the dry season or during prolonged drought, narrowly lanceolate-acuminate, up to 200 mm long, 35 mm in diameter, with a grey-green surface. Inflorescence simple or sometimes branched, pendulous, recurved, up to 250 mm long, the racemes in a head (capitate). Flowers are sub-pendent, the perianth is orange-red, green-tipped, 20 mm long. Fruiting capsules are 9–12 x 4 mm, ascending-spreading. Seeds are winged, grey, 3 x 2 mm. Flowering time is mainly in midsummer and autumn (December to April), but sporadically at other times as well.
Fig. 2. Close-up of the rounded flower head of Aloe meyeri on the Rosyntjiesberg, Richtersveld National Park (N. Cape).
Conservation Status
Status
Although Aloe meyeri is classified as Rare on the Red List of South African plants, because of its safe, inaccessible, cliff-face habitat falling within the Richtersveld National Park, it is not threatened.
Fig. 3. Aloe meyeri cluster on a south-facing quartzitic sandstone cliff on the Rosyntjiesberg, Richtersveld National Park (Northern Cape).
Distribution and habitat
Distribution description
Aloe meyeri is confined to the upper slopes of the Rosyntjiesberg (Richtersveld National Park, Northern Cape) and adjacent area of the same geological formation in southern Namibia.
The habitat of Aloe meyeri consists of vertical or near vertical, quartzitic sandstone cliffs, growing at altitudes of 300–1 200 m above sea level. The geology consists of quartzitic sandstone of the Rosyntjieberg Formation (Orange River Group). This rock formation has many fissures, ledges and crevices and is ideal for establishment of plants. The vegetation of the Rosyntjiesberg consists of Rosyntjiesberg Succulent Shrubland of the Succulent Karoo Biome (Mucina et al. 2006).
Aloe meyeri grows both on exposed northern and northwestern aspects, but also on southern and eastern slopes, the plants firmly rooted in crevices. The average daily maximum temperature is about 26ºC and the average daily minimum about 14ºC, with frost absent in winter. The southern slopes are cooler, with shady conditions. Winters are cool and subject to occasional coastal fog from the west coast. Rainfall occurs mainly from autumn (thunder showers) to spring (cyclonic winter rain), ranging from 75–150 mm per annum.
Associated cliff dwelling plants in its habitat are Conophytum taylorianum subsp. rosynense, Crassula garibina and C. montana subsp. borealis, Othonna cremnophila, Trachyandra aridimontana and Tylecodon ellaphieae.
Derivation of name and historical aspects
History
Aloe meyeri was named by the author in the Journal of South African Botany in 1981 (Van Jaarsveld 1981). It commemorates the late Reverend G. Meyer of Steinkopf, who first collected the plant in September 1939, together with the late Mr Hans Herre of the Stellenbosch University Botanical Garden. Their discovery was brought to the attention of Mr N.S. Pillans and Dr G.W. Reynolds but, according to Hans Herre, they considered it to be a hybrid between Aloe krapohliana and another aloe (Herre 1973).
The author came across this aloe on an expedition arranged by Pieter Drijfhout, collecting material of Pelargonium desertorum on the southern foothills of the Rosyntjiesberg, in June 1980. Upon investigation, and after reading the 1973 article by Herre, where he mentioned the discovery of an aloe by Meyer on the Rosyntjiesberg, he realised the significance of Meyer’s find and subsequently named it for him.
Aloe meyeri belongs to a group of 7 aloes belonging to section Mitriformis, subsection Prolongatae (see Aloe dabenorisana). This group is mainly confined to the winter rainfall region of southern Africa. Aloe meyeri is closely related to A. pavelkae which is only known from the Hunsberg Mountains in southern Namibia. Aloe meyeri is easily distinguished from this related group by its smaller, 20 mm long, green-tipped flowers. Aloe pavelkae has green leaves and a distinct apical rosette and the leaves when turgid, do not become biconvex and it flowers in midwinter. Aloe meyeri is smaller, with glaucous leaves that remain functional over a considerable part of the stem (leafy stems), and flowers in midsummer. Aloe dabenorisana has similar green leaves, but they are recurved.
Fig. 4. The leafy stem of Aloe meyeri, note the turgid succulent leaves and small teeth.
Ecology
Ecology
A slow-growing, long-lived perennial with sturdy leaves, that grows on sheer cliffs, and the drooping stems and spreading to ascending leaves, are well adapted to the exposed and shady, south-facing cliffs. During dry conditions, the leaves fold in, protecting the growth point and younger leaves.
This species retains its pendent leafy stems and leaves, even when growing in cultivation. Compared to related plants in subsection Prolongatae (Reynolds 1950), there is a general reduction in size; it is the smallest in the subsection. Its smaller size also allows for more effective anchorage of the rootstock, allowing it to cope more efficiently with gravity. Plants of smaller size can also cope better with heat absorption under cool growing conditions, a general trend among winter-active succulent plants.
The persistent leaves remain functional for many years, thus acting as a water resource and staying photosynthetically active. The small teeth on the leaf margins suggest a reduction in armament as a direct result of the reduction in herbivory, because of the sheer cliff face. The herbivores with which the plants have to deal, include the Chacma Baboon (Papio ursinus), Rock Rabbit (Procavia capensis) and Klipspringer (Oreotragus oreotragus). When seed germinates on accessible sites, the plants will be grazed by these herbivores, and the young inflorescences and soft new young stems by the baboons.
The young inflorescence is drooping at first but curves up as it matures, presenting the raceme(s) in the typically erect position, however, the flowers remain pendent. Pollination is by local sunbirds. The fruits ripen in autumn, with the start of the rainy season, when there is the best chance of thunder showers which are followed by cyclonic winter rains. As the capsule matures it is held in an erect position, and a gust of wind will shake the small, light, winged seeds out and scatter them on the cliff, their size and angular shape ideal for establishment in crevices.
Aloe meyeri is prolific from the base, forming drooping clusters. The stems root when finding a new crevice and fallen branches will also root when wedged in a suitable crevice. The continual renewal of shoots and rooting of stems in new crevices by extended stem growth, represent a vegetative backup dispersal strategy for the harsh cliff-face environment.
Fig. 5. Close-up of a rosette of Aloe meyeri growing on a sheer rock face, note the faintly striate leaves.
Uses
Use
It is not known whether the plants are used medicinally.
Fig. 6. A cluster of Aloe meyeri, note the long stems.
Growing Aloe meyeri
Grow
Aloe meyeri is best grown in succulent karoo gardens. It does best on sheer embankments or on a balcony. Plants can be grown from seed or cuttings. It is best grown as a specimen pot collection outside its native habitat. In moist environments, plants may become prone to fungal crown rot. It does well in a sandy, well-drained soil. Keep dry in summer.
Outside its habitat, plants usually struggle. For best results, in a desert garden situation, grow on steep embankments where the plant can become drooping. Soil should be slightly acidic and rich in gravel. Water should be provided sparingly throughout the year. Propagate from stem cuttings, rooted in sandy soil in summer. Keep in light shade.
Outside of its desert habitat it is best to grow in a greenhouse in a container or hanging basket, where its climate can be controlled and its habitat simulated. Grow in a sandy, slightly acidic medium, adding an organic fertiliser during watering. Water sparingly throughout the year.
Propagate by seed or by stem cuttings. Place offshoots in a sandy soil. Best time is in spring and summer. Seed is fine and can be sown in a sandy mixture, in spring or summer and covered with a very thin layer of gravel or sand. Keep moist. Remove seedlings as soon they are large enough to handle.
In moist climates the fungus Fusarium can damage the roots. Best to add Trichoderma, a fungal biological control agent. Aloe cancer caused by microscopic mites can sometimes be troublesome causing distorted growth of the inflorescence or stem, but is easily treated with a paint brush and Karbadust mixed with water. Paint the infected cancerous portion. If the tuberous growth is large it can also be removed by hand and the wound painted. Roots sometimes affected by mealybug and treat accordingly, drenching the plant in a contact or systemic insecticide.
References
- Herre, H. 1973. Herrineringe van ‘n besoek aan die Richtersveld. Aloe 2(1): 18.
- Mucina, L. & Rutherford, M.C. (eds) 2006. The vegetation of South Africa, Lesotho and Swaziland. Strelitzia 19. South African National Biodiversity Institute, Pretoria.
- Reynolds, G.W. 1950. The aloes of South Africa. Trustees of the Aloes of South Africa Book Fund, Johannesburg.
- Van Jaarsveld, E.J. 1981. Aloe meyeri Van Jaarsveld—a new Aloe from the north-west Cape (RSA). Journal of South African Botany 47(3): 567–571.
- Van Jaarsveld, E.J. 1981. Aloe meyeri: ’n nuwe aalwyn van die Richtersveld (Noordwes-Kaap). Veld & Flora 67(2): 72, 73.
- Van Jaarsveld, E.J. 2006. Cultivation of South African and Namibian cliff-dwelling succulents with pendent growth forms. Cactus and Succulent Journal (U.S.) 78(6): 268–283.
- Van Wyk, A.E. & Smith, G.F. 2001. Regions of floristic endemism in South Africa. A review with emphasis on succulents. Umdaus Press, Hatfield, Pretoria
Credits
Ernst van Jaarsveld
Kirstenbosch National Botanical Garden (Retired 2015)
Babylonstoren Farm
Extraordinary senior lecturer and researcher,
Department of Biodiversity and Conservation, University of the Western Cape
January 2021
Plant Attributes:
Plant Type: Succulent
SA Distribution: Northern Cape
Soil type: Sandy
Flowering season: Late Summer
PH: Acid, Neutral
Flower colour: Green, Red, Yellow, Orange
Aspect: Shade, Morning Sun (Semi Shade)
Gardening skill: Challenging
Special Features:
Attracts birds
Drought resistant
Good potplant
Indoor plant
Horticultural zones
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