Rare palms, blue cactus, a yellow camellia, giant ferns and Sydney's own Gymea Lily feature in this months virtual tour of the Royal Botanic Garden Sydney.
Spindle Palm – Hyophorbe verschaffeltii
This palm is endemic to the island of Rodrigues in the Indian Ocean, part of the republic of Mauritius. Although common in cultivation it is critically endangered in the wild. A 2019 report found only 19 truly wild plants from 9 locations on the island. There is no evidence of natural regeneration and plants are threatened by grazing, land clearing and hybridising with the introduced Bottle Palm (Hyophorbe lagenicaulis) from Mauritius. More than one thousand Spindle Palms have been propagated and planted across Rodriques island.
Giant Fern – Angiopteris evecta
Angiopteris evecta belongs to a family of ferns that has been shown to date back 300 million years and was distributed on all continents. Now their distribution is restricted to tropical Australia and Asia. Their large trunks can be 3 m high and 1 m across and the fronds that unfurl from the centre are the largest of any fern. Fronds can reach up to 8 m long and are supported entirely by turgor pressure of the sap within the cells, so if they dry out they will collapse.
Golden Camellia – Camellia petelotii var. petelotii (syn. nitidissima)
This yellow camellia is endemic to southeast China and Northern Vietnam and is one of about 30 species of yellow camellias. It was originally described in 1949 and was brought into cultivation and made available outside China in the late 1970s. The small, buttery yellow flowers are followed by large, smooth, green fruits that look like a small apple. It is used in China for tea and traditional medicine. Wild populations are now threatened due to over collection and habitat loss.
This white flowering camellia from China has heart-shaped petals and a delicate fragrance. This small tree produces fruit that is harvested for its seed, used to produce camellia oil used in margarine, soap and cosmetics. It is widespread in southeast China but there is insufficient data to confirm if it is threatened in the wild, despite reports of declining populations due to deforestation and other pressures from increased human populations. A double-flowered form, called Zhenzhu Cha, is planted nearby.
Blue Column Cactus – Pilosocereus pachycladus
There are about 50 species of cacti in the genus Pilososcereus, named from the Latin pilosus, meaning hairy, and cereus, meaning torch or candle. This species from Brazil is one of the most spectacular columnar tree-like cacti and one of the bluest of the genus. It is found at elevations of 50–1550 m above sea level in rocky quartz outcrops. It can grow up to 10 m tall and has hairy aeroles with golden spines that turn grey with age.
Gymea Lily – Doryanthes excelsa
Named from the Greek word doratos meaning spear and anthos meaning flower, there are only two species in this genus, both endemic to Australia. Gymea lilies come from the central coast and north coast, including the Sydney basin but there are large gaps in between where the plant is not found. They are well known for their striking red flowers at the end of a long spike that reach 6 m high and attract many species of birds who feast on the nectar. The other species in the genus, Doryanthes palmerii is from northern NSW and southern Queensland.
Klinki Pine – Araucaria hunsteinii
Endemic to the central and eastern highlands of New Guinea, this southern hemisphere conifer is a close relative of the Bunya Pine (Araucaria bidwillii) with some outstanding features of its own. It is the tallest in the genus, the tallest recorded at 90 m, and often emerges to be twice as high as the surrounding forest canopy. It has the largest leaves of the genus and does not shed leaves but drops branchlets intact. The unusual reddish-brown bark peels off in plates creating interesting patterns.
Hong Kong Orchid Tree – Bauhinia x blakeana
This spectacular pink flowering tree was found around 1880 at Pokfulamin in Hong Kong by a French missionary who propagated it from a cutting. In 2005 scientists showed it to be a naturally occurring hybrid of two other Bauhinia species, Bauhinia variegata and Bauhinia purpurea but it is sterile. It does not produce fruit even when flowers are deliberately pollinated. Hence it only exists due to human intervention through vegetative propagation so this tree is genetically identical to that first tree discovered in 1880.
Why not join a Guided Walk of the Garden with one of our knowledgeable Volunteer Guides, daily at 10:30 am. Find out more here.