Tuesday, May 06, 2008

Tarchonanthus littoralis P.P.J.Herman


Family : Asteraceae (daisy family) Common names : coastal camphor bush ( Eng. ); kuskanferbos (Afr.); isiduli selindle (Xhosa); igqeba-elimhlophe, isidulu-sehlathi (Zulu). For a small evergreen tree that will thrive in windy, coastal conditions, through drought, and in nutrient-poor, sandy soil, look no further than Tarchonanthus littoralis. Readers may know it better as T. camphoratus, but a recent study has shown that T. camphoratus was made up of five distinct species that have now been individually named and described. The revised T. camphoratus occurs in the northern part of southern Africa whereas this recently defined species occurs along the south and southeastern coast of South Africa. Description Tarchonanthus littoralis is a large, dense, bushy shrub or small, shapely tree, 1–8 m tall. The trunks are often crooked, and the trees often multi-stemmed. The bark is vertically fissured and cracked, flaking off in narrow strips. Young growth is densely hairy. Leaves are strongly aromatic and leathery. The colour of the upper and lower surfaces of the leaves are distinctly different: the upper surface is dark green, hairy when young but becoming hairless; the lower surface is white-grey and covered in a dense mat of velvety hairs. The main vein is sunken, particularly in the lower half and the leaf contains a fine network of veins, which is clearly visible on both surfaces. The margin is very often faintly and minutely toothed in the upper part (on the Kirstenbosch plants, this is most easily seen on the young coppice growth). Tarchonanthus littoralis is dioecious, meaning that the male and female flowers are carried on different trees. Peak flowering time is during mid to late summer (December–March). On both male and female trees, the individual flowers are borne in small flower heads which are grouped into large, branched, terminal inflorescences. Male flower heads are 5–10 mm in diameter and contain 13–47 flowers, each tiny flower a 5-lobed, funnel-shaped tube, ± 3 mm long, with recurved corolla lobes. The anthers are ± 1.5 mm long and protrude beyond the tube. The male flowers have a sterile ovary and a long, protruding style (up to 8 mm), which is a noticeable feature of the flowers. The anthers are the striped structures surrounding the base of the style. The female flower heads are ± 5 mm in diameter and are made up of only 3–6 tiny flowers. Each flower is a 5-lobed, funnel-shaped, ± 2 mm long tube with recurved corolla lobes. The style is ± 3 mm long with 2 short branches, and protrudes beyond the corolla lobes. The fruit is an achene, ± 4 mm long and is densely covered in white, woolly hairs. Both the male and female flowers are white to cream-coloured but the bracts that surround the flowers and the stalks are creamy brown and so the overall colour of the inflorescence is a yellowish cream and the trees are attractive while in flower. A month or so after flowering, each female flower has become a cotton-wool-like ball of shiny white fragrant hairs, that fluffs out more as it matures. The small seed is buried inside the puff of white hairs. The brown star in amongst the woolly hairs is the remains of the corolla tube and style. The white fruiting inflorescences are extremely showy against the dark green foliage, and remain decorative for many months. While the female trees are still looking beautiful, the male flowers are dead and brown and the male trees are quite drab in comparison.

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