Gasteria polita

Van Jaarsv.

Family:
Aloaceae (Aloe family)
Common names:
polished gasteria, polished ox tongue

 

FlowersGasteria polita is a recently discovered species that is both attractive and easy to grow.

Gasterias are aloe-like plants, in fact they belong in the same family, Aloaceae. They are drought-tolerant, leaf succulents, and most species are confined to the south eastern part of South Africa.

Description: Gasteria polita plants are small, solitary, stemless rosettes up to 120 mm high and 250 mm in diameter, occasionally proliferating from the base to form small clusters. Each rosette is made up of short, shiny, distinctly keeled leaves, each one triangularly strap-shaped, first ascending then becoming spreading, 60-120 x 30-40 mm.Gasteria polita The leaf margin and the keel are studded with prominent white tubercles (wart-like growths) and the blunt leaf ends also have tubercles. The juvenile leaves are smooth, strap-shaped and presented in opposite rows (distichous).

The inflorescence is a simple raceme up to 600 mm long, although some adult plants may bear a pair of side branches. The individual flowers are tubular, 35 mm long and 6 mm in diameter. They are reddish pink with the upper half white with green striations (fine lines). Flowering season is in summer (end of October to December). The fruiting capsule is 24 x 7 mm, and the seeds it produces are black, 3-4 x 2-3 mm.

Distribution: Gasteria polita is the only gasteria solely confined to afro-temperate forest habitat and is known only from the Plettenberg Region in the eastern end of Western Cape. Most other species are confined to thicket, succulent karoo and dry savannah. G. polita occurs on rocky outcrops in scrub forest and grows in sandstone rock crevices in the shade of thickets or in humus-rich rock pockets. It shares its habitat with other succulents such as Aptenia cordifolia, volstruisnek (Euphorbia clava), brosplakkie (Adromischus inamoenus), rooistingelplakkie (Crassula rubricaulis), C. nudicaulis, C. cultrata, sosatieplakkie (C. perforata), money-plant (Plectranthus verticillatus), fransaalwyn (Aloe pluridens) and the kraal aloe (A. arborescens). Non-succulent shrubs and small trees include baviaanskers (Euclea polyandra), gonnabos (Passerina falciformis), Psyderax obovata, Ochna serrulata and Maerua raemulosa. It is closely related to G. acinacifolia, a larger coastal species from the Strandveld regions between Knysna and East London. It is the small size of G. polita that immediately distinguishes it from the larger G. acinacifolia.

Derivation of the name: The genus name Gasteria is from the Greek, gaster, meaning belly, and alludes to the swollen base of the perianth tube. The specific epithet, polita, literally means polished and refers to its dark, mottled leaves which have a polished appearance. Gasterias are locally known by the common name ox tongue (beestongblaar in Afrikaans), because of their tongue-shaped leaves.

Gasteria polita was only recently discovered by the forester Mr Rynhard Kok at Whisky Creek near Plettenberg Bay in Western Cape and was described by Van Jaarsveld (2001). It is one of the 19 known Gasteria species, all of which are endemic to southern Africa.

Growing Gasteria polita

Although most gasterias perform well as pot plants in cultivation, Gasteria polita is particularly easily cultivated, thanks to its native habitat. It occurs on sandstone outcrops in slightly acid, humus-rich soil in an area that receives a high rainfall throughout the year. To survive here, plants have to tolerate disturbances by forest herbivores such as bushpig, porcupine and bushbuck. As a result, broken leaf fragments root readily when dropped on the forest floor, proliferating to form new plants. The plants are also adapted to low light intensity which makes them perfect to grow in our homes. Gasteria roots are usually sensitive to fusarium root rot brought about by excessive watering, but G. polita is remarkably resistant to this fungus, again thanks to its adaptation to the moist forest habitat and fog from low clouds, and will tolerate over-watering as long as the pots are well drained.

Gasteria polita can be used as a pot plant on window sills or on verandas, or outside in a rockery provided that frost is not severe. They prefer partial or dappled shade, so plant them on the shady side of rocks or underneath shrubs. They grow well in combination with other succulent plants. Plants can be given an annual dressing of compost placed on top of the soil. Any organic fertilizer may be used if compost is not available. Gasteria polita is tolerant of a wide range of soil and also grows well in the winter rainfall Western Cape gardens where it should be occasionally moistened during the dry summer months.

Propagation: Gasteria polita is easily propagated from leaf cuttings or seed.
Seed: Cross pollination of Gasteria polita flowers is essential for the production of viable seed. In habitat the nectar-rich, tubular flowers are pollinated by sunbirds but in cultivation, particularly in a nursery, cross pollination must be done by man. To pollinate, mimic the action of the sunbird, i.e. find a small stick, like a sharpened match-stick, gently insert it into a flower on one plant then transfer the pollen that rubs off onto the stick onto the stigma of a flower on another plant. Capsules abort very soon if the flowers are not pollinated or if pollination was unsuccessful. Seed should be sown during spring or summer. Sow in a sandy, well-drained potting soil using standard seed trays. Cover with a thin layer of sand (1-2 mm), place in a warm, shady position and keep moist. Germination occurs within 3 weeks. The seedlings are slow growing, and can be planted out into individual bags as soon as they are large enough to handle. Flowering occurs within 3 to 4 years.
Cuttings: Gasteria polita can also be propagated by leaf cuttings. After removing a leaf from the adult plant, let it lie for about 1 month for the leaf to form healing tissue. Then lay it on its side with the basal parts in potting soil. These should root within a month or two and small plants will form at their bases. These can be planted out as soon as they are large and firm enough to handle.

References

  • VAN JAARSVELD, E.J. 2001. Gasteria polita, a new species from the Western Cape. Cactus & Succulent Journal (US) 73: 127-130.
  • VAN JAARSVELD, E.J. 1994. Gasterias of South Africa. Fernwood Press, Cape Town.

Ernst van Jaarsveld
Kirstenbosch National Botanical Garden
January 2003



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