December 18
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Plant Genus of the family Araucariaceae

Genus Description Cultivation
Afrocarpus The 6 or so species of this African genus of conifers were until recently included in Podocarpus (and for a brief period in Nageia). In their native habitats they are tall forest trees with massive trunks and occur in widely separated mountain regions of central, eastern and southern Africa. One species is known only from the island of Sao Tom? off Gabon, while another, Afrocarpus usambarensis from the Mitumba Mountains of Uganda and Rwanda, is thought to be Africa?s tallest tree, at up to 250 ft (75 m). All species have attractive bark that peels off in flakes or strips from older trunks. Leaves are leathery and narrow, like larger versions of yew leaves. As in most podocarps, male (pollen) and female (seed) organs are borne on different trees; however it is the female ?cones? that provide the main character distinguishing Afrocarpus from Podocarpus. Instead of having a swollen, fleshy stalk with one or two tough-skinned seeds attached to its apex (as in Podocarpus), they have a relatively thin stalk with a single, usually larger seed that has a thick, juicy outer layer and an inner ?stone? surrounding the embryo. The seed thus mimics the fruits of some flowering plants, such as cherries. The Asian genus Nageia is somewhat similar, but differs in having leaves with no midvein. CULTIVATION: These are somewhat slow-growing trees, suitable for planting in parks and avenues in warm-temperate and subtropical climates with adequate rainfall. Given a deep, well-drained and reasonably fertile soil they continue to increase in girth and crown spread for a century or more, developing a dense, shade-giving canopy when growing in the open. They are affected by few pests or diseases and require almost no shaping. Propagation is normally from seed, sown fresh after removing the fleshy coating.
Agapetes Belonging to the vaccinium subfamily of the heaths, this genus consists of over 90 species of low, often creeping or scrambling shrubs native to tropical and subtropical Asia, the Malay Archipelago, some larger Pacific islands and the far northeast of Australia, where a single species occurs. Mostly found in mountain rainforests, many grow as epiphytes on moss-covered tree trunks or rock outcrops. Most send out roots from prostrate or arching stems and some develop woody tubers at the stem base, which may be buried in the litter that accumulates in the forks of trees. Leaves vary greatly between species but are mostly leathery and new growth flushes are often colored pink, red or orange. The flowers, emerging singly or in small sprays from leaf axils, are tubular and rather waxy with a strong tendency to be 5-angled or 5-ribbed. Most Agapetes species have the potential to be interesting garden or conservatory plants. CULTIVATION: Most species can be grown outdoors in sheltered positions in a mild, frost-free climate, while some of the Himalayan species will cope with a few degrees of frost, though even these are best planted under trees. They are best suited to a well-drained spot such as the top of a bank or among rocks and an acidic, humus-rich soil. As conservatory plants they prefer a peaty medium in a large pot or hanging basket, and should be kept in a good light with regular watering and misting. Propagation is most easily effected by layering, although cuttings can also be used.
Agathis Few conifers grow into quite such massive trees as do many of the 13 species of Agathis, or kauri. The genus is of great evolutionary interest, representing a major element in the temperate rainforests that covered much of the southern supercontinent of Gondwana in the Cretaceous period (around 120 million years ago) but which had shrunk to small remnants by the mid-Tertiary period (30 million years ago). This history is shared by its close relatives Araucaria and the recently discovered Wollemia, the 3 genera forming the unique conifer family Araucariaceae. Agathis has an interesting distribution, with species scattered through an arc stretching from Sumatra in the northwest to New Zealand and Fiji in the southeast. New Zealand has a lone native species, there are 5 species native to New Caledonia, and northeastern Australia has 3 species; the others occur mainly in New Guinea and the Malay Archipelago. ?Kauri? is Polynesian; ?kaori? is used in some Melanesian islands. Young kauri trees grow vigorously skyward with a straight smooth trunk, but with age develop massive ascending limbs fairly high in the crown. The bark peels off in rounded scales of different size, shape and color in different species, producing some distinctive patterns. Leaves are broad and leathery with no midrib, arranged in almost opposite pairs. The cones are more or less globular with tightly packed scales, their junctions tracing out criss-crossing spirals?a pattern that inspired the genus name, which is the Greek word for a ball of twine. At maturity the cones shatter into disc-like pieces, releasing thin-winged seeds which twirl gently groundward. CULTIVATION: Agathis grow readily in the wet tropics and in frost-free temperate climates. The New Zealand kauri is probably the only one that can tolerate several degrees of frost, though the Australian species can survive light frosts if grown in a protected spot. They prefer deep soil with reliable subsoil moisture and are known to reach very large sizes on deep coastal sands. Height growth may be quite fast, but a large trunk diameter takes many decades to achieve. Propagation is only practicable from seed, gathered as soon as it falls and sown immediately.
Anopterus This genus of attractive small evergreen trees and shrubs consists of only 2 species, one endemic to Tasmania and the other to mainland eastern Australia, both growing in tall forest in high-rainfall mountain and foothill regions. It belongs to a group of flowering plant families that include the saxifrages, currants and hydrangeas. Botanists are still to determine the relationships within this complex group. Anopterus species have a distinctive habit, with erect branches on which the elongated leathery leaves tend to be crowded together at the ends, somewhat like the arrangement of rhododendron leaves. Short spikes of funnel-shaped white flowers terminate the shoots, and new leafy shoots emerge laterally from below these. The fruit is a leathery capsule that splits into 2 halves to release winged seeds. Both species of Anopterus make interesting ornamental plants. CULTIVATION: For planting outdoors they require a mild, humid climate. The Tasmanian species tolerates moderate frosts while the mainland species is less frost hardy but more tolerant of warmth. A sheltered, slightly shaded situation and moist but well-drained soil suits them best. They also make attractive conservatory plants in cooler climates, worth growing for the foliage alone. Propagation is from seed or cuttings; plants grown from cuttings flower at a much smaller size.
Antiaris This genus is composed of 4 species of deciduous trees found in tropical areas from Africa through the islands of the Indian Ocean to the Philippines. Although members of the mulberry family, the Moraceae (some place them in the nettles, the Urticaceae), unlike most members of that group their fruit, indeed the whole tree, is poisonous. They have large, broad, roughly hairy leaves and separate male and female flowers, the males in small heads and the females borne singly. The flower stems and the drupe-like fruits are covered in fine hairs. CULTIVATION: Easily cultivated in the seasonally dry tropics, these trees are quite attractive with their large leaves and showy drupes, but they are somewhat risky as children may be tempted to sample the fruit. Plant in full sun in moist, well-drained soil with ample humus. The leaves tear easily and are best sheltered from strong winds. Propagate from seed, layers or by grafting.
Aphelandra This genus in the family Acanthaceae consists of about 170 species of shrubs and subshrubs cultivated for their attractive flowerheads. Short-lived red and yellow flowers appear throughout the year. Native to tropical North, Central and South America, all species are frost tender and live in the wild as understory plants in moist woodland. CULTIVATION: To grow in pots, combine a loam-based compost in the ratio 2:1, with one part of leaf mold. These plants thrive when watered with rainwater (soft water). They should be fed regularly through the growing season, and then food and water reduced throughout dormancy. Drafts and direct sunlight should be avoided. After flowering, plants need to be cut back to encourage side shoots, which can be used for propagation. Spider mite, aphids and scale insects can be a problem under glass. In the wild the plants are pollinated by hummingbirds.
Araucaria This ancient and remarkable conifer genus consists of 19 species, of which 13 are known only from New Caledonia and its satellite islands. Of the remaining 6 species, 2 occur in South America, 2 in eastern Australia, 2 in New Guinea (one shared with Australia) and one on Norfolk Island. Araucaria, Agathis and the newly discovered Wollemia make up the unique family Araucariaceae, fossils of which go back as far as the Triassic Period (more than 200 million years ago) in various parts of the world, but which is now almost confined to the Southern Hemisphere. Araucarias have a distinctive growth habit with a straight trunk and usually whorled branches; the spirally arranged leaves are densely crowded and often overlapping on flexible branchlets. In some species individual leaves may live for many years, so that quite thick branches are still clothed in green, while in others whole leafy branchlets are cast off after a very few years? growth. Male and female organs are on the same tree, the tassel-like pollen cones hanging from the side branches, and egg-shaped seed cones with spine-tipped scales clustered near the top of the crown. The seeds, which may be quite large and nut-like, are embedded in the tough cone scales, a feature unique to this genus. CULTIVATION: Cold tolerance of the species varies, though nearly all will survive slightly lower winter temperatures than their native habitats experience, but none can be grown outdoors in severe climates such as continental northern Europe. In such climates they are grown as conservatory plants and may be kept in tubs for many years. In warmer climates araucarias are grown as landscape subjects in large gardens, parks and avenues. Propagation is usually from fresh seed which germinates readily; cuttings will strike using modern techniques, but tend strongly to retain sideways growth if taken from lower branches.



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