Encephalartos Latifrons

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Encephalartos Latifrons

Encephalartos latifrons, also known as the Albany Cycad, occurs in South Africa in the biodiversity hotspot region known as the Maputaland-Pondoland-Albany hotspot, which is an important center of plant endemism. It is uncertain how widespread or abundant Encephalartos Latifrons was prior to human settlement, but there are historic records of populations being scattered through the Albany and Bathurst districts of the Eastern Cape Province. It is in a critical state with no natural seed set and continuing decline.

Based on plants in collections and studies of matched photographs, the population has declined by >80% over the past 100 years. The area of occupancy is estimated to be 9 km² and the population is extremely fragmented with most individuals separated from each other by more than by one kilometer. The sex ratio is ca. four males to one female so that the effective population size is extremely small. All subpopulations comprise less than 20 plants, which is non-viable for supporting pollinators and there appears to have been no recruitment for more than 50 years.

Stems of Encephalartos Latifrons are up to 3m tall, and even as tall as 4,5m in exceptional cases, with a diameter of 30cm to 45cm. Stems may be single but are more usually branched from the base, sometimes forming a number of stems and suckers. Before new leaves emerge, the crown of the stem becomes woolly. The beautiful broad leaves of E. latifrons may be 1m to 1,5m long with the top half or third, recurved or completely curled back. The mature leaf is hard and rigid, with a glossy dark green colour. The glossy rachis is clear and yellow. The young leaf is covered by fine hairs, which are lost with age. The petiole is 10cm to 20cm long and the leaf base has a conspicuous yellow-white collar. The leaflets are attached to the rachis in a V-form, which is narrower towards the top of the leaf. The leaflets at the middle of the leaf are 10cm to 15cm long and 4cm to 6cm broad, excluding the lobes. The leaflets are 1,5cm to 2cm broad where they are attached to the rachis. The tips of the leaflets (and of the lobes) are pointed and fairly sharp. The upper margin of the leaflet is usually smooth, but may sometimes be toothed. The lower margin of the leaflet carries 2 to 4 triangular lobes, which are twisted out of the plane of the leaflet. The leaflets overlap upwards, especially in the top third of the leaf. Viewed from the side, the lowest lobes point downwards and the upper ones upwards, to form an interlocking pattern, which is very characteristic of the species. The leaflets are usually prominently nerved, especially on the under-side. The leaflets become more widely spread on the rachis towards the base of the leaf and become reduced in size. Only the very lowest ones sometimes become prickle-like, however. Some variation occurs in the appearance of the leaves, as is found in many other species. Some leaves are more sharply recurved than others while the leaflets may be generally smaller in some than in others. Some collectors believe that there are observable differences between the leaves of male and female plants. One to three cones may be formed. The colour of the cones is dark olive-green or dark bluish-green. The cones are carried on very short stout stalks. The cone scales are sparsely covered with fine hair. The male cone is almost cylindrical in shape and 30 to 50 cm long and 8 to 17 cm in diameter. It becomes narrower towards both ends.

The scales at the middle of the cone are approximately 6cm to 7cm long and 3cm to 3,5cm broad, with prominent 2cm long beaks, which are curved downwards or sideways. The upper and lower surfaces of the scale are variably ribbed. The female cone is barrel-shaped, 50cm to 60cm long and 25cm in diameter, with a mass of up to 27kg. The median cone scales are about 8,5cm long and 5,5cm broad. The scale face protrudes 2cm to 2,5cm and is deeply furrowed, wrinkled and pimply. There are usually approximately 15 spirals of scales.

The seeds are red in colour and large, approximately 5cm long and 2cm to 2,5cm in diameter. They are angled as a result of compression and have a fleshy beak.

Cultivation:

semi-shade dark green low watering slow growth frost-resistant rare
semi-shade dark green low watering slow growth frost-resistant rare

The relatively few collectors who possess mature specimens of E. latifrons have found that they grow well in cultivation, as is obvious from the healthy plants in the fine collection at Kirstenbosch Botanic Garden in Cape Town, which was started more than 70 years ago. The plants need very good drainage, however. They would also require sufficient moisture and protection from frost.

Encephalartos Latifrons has the reputation of being a very slow grower. Professor Charles Joseph Chamberlain came to this conclusion during his visit to Trappes Valley, near Grahamstown, in 1912 (Chamberlain, C.J. The Living Cycads). He spoke to ‘a pleasant, gray-haired lady’, the owner of a house where two specimens of Encephalartos Latifrons and three of Encephalartos Latifrons were growing in the garden. According to her, the plants were planted there ‘when she came to that house as a bride forty-six years before’. She thought that the specimens of E. altensteinii might have grown 25cm during that time, but ‘that the Encephalartos Latifrons did not seem to have grown any, although they always had green leaves’. Two or more years may pass between the formation of sets of leaves.

Growing Encephalartos latifrons

Although Encephalartos latifrons is very slow growing, this species does well in cultivation provided that it is planted in well drained soil, enjoys full sun and a cool winter without frost; it does not do well in subtropical climates. In its natural habitat, E. latifrons is subject to hot, dry summers and cool, frost-free winters. The high humidity and warmer winters in subtropical regions are probably not suited to this species. High pressure irrigation systems, which produce a strong jet of water, are to be avoided as they are fatal for all species of cycad. The strong jet of water will destroy the leaves as well as the stem of the plant. Cycads require regular feeding to maintain a healthy plant. A 50 mm thick mulch of well-matured compost applied in the autumn helps to improve the soil and benefits the cycads. In the early spring apply a mixture of bone meal, organic fertilizer and a balanced inorganic fertilizer to each plant.

Large specimens make excellent accent plants surrounded by lower growing species such as E. horridus, with the grey leaves contrasting well with the dark green leaves of E. latifrons. Young plants make ideal container plants. Good, sharp drainage is essential with regular watering plus annual feeding which will keep the plant healthy.

Scale and mealybugs, which are found on the underside of the leaves, could be a problem. Spray with a systemic insecticide. Mature plants when coning could attract snout beetles which destroy the seed. A contact insecticide needs to be applied to eliminate them. As new leaves appear they can be damaged by a tiny mite. A contact insecticide needs to be applied regularly every two weeks when the new leaves start appearing.

Encephalartos latifrons has been cultivated at Kirstenbosch since 1913 and propagation by seed has been poor, with below 10% germination. Recently (2014), the Kirstenbosch research team has solved the low seed germination problem. Hand pollinating the female cone with pollen harvested from a male cone is necessary in ex situ collections for production of viable seed and prevention of hybridization.  In the past, at Kirstenbosch, hand pollination was carried out using the wet hand pollination method. However, an M.Sc. research study showed that wet pollination negatively affects seed embryo development and subsequent seed germination, compared to dry pollination. The study recommends dry pollination in the afternoon period when pollination droplets are abundant. Furthermore, after natural cone disintegration, seeds should be dusted with powder fungicide and stored for 12 months in relatively dry conditions. The recommended protocol yields over 50% seed germination.

Stored seed can be sown in summer on a bed of clean sand which has bottom heat of between 25–28°C. Within five weeks, the seeds start germinating, first producing a radicle followed by the leaves. By the following spring the seedlings are large enough to be planted and into a 3 litre plastic sleeve. A well-drained growing medium is essential. Until established, the young seedling must be watered sparingly.

The other method of propagation is by removing well-developed suckers, a minimum of 250 mm in diameter, from the parent plant. Remove all the leaves before carefully pulling them away from the main stem. The sucker should be left to dry off the wound before planting in clean sand to encourage rooting. Once well rooted, the sucker can be planted out into the open ground.

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