Belfast Botanic Gardens Tropical Ravine
Planting in the restored Tropical Ravine
The Cycad Collection
The cycads are seed plants, one of the groups on non-flowering seed plants that evolved in the Mesozoic, long before the first flowering plants. There are 9 or 10 genera of cycads and several hundred species mostly from the Southern Hemisphere. The cycad collection is extensive and growing; a few are included below.
There 116 species of the genus Cycas
. Cycas revoluta
is probably the best known of all cycads. Almost all botanic gardens have one and it may be found in domestic gardens in milder temperate regions. Although it is hardy to -10degC, at this temperature it will lose all its leaves and behave as a deciduous plant. The plant, its seeds and pith are poisonous, but in spite of this, sago an edible starch is made from the pith of the plant - repeated washing removes the toxins. The plant is extremely poisonous to animals; the cycasin toxin can cause permanent internal damage and it is also carcinogenic. As with all cycads Cycas revoluta
is dioecious - having male and female cones on separate plants. The species name revoluta
refers to the twisted leaves.
|Cycas revoluta in the Tropical Ravine
||The twisted leaves
Cycas revoluta from above
This is the largest cycad in the tropical end of the Ravine. The plant is a male and has produced two pollen cones (in 2017). It is one of the plants that had to remain in the Ravine during the building works and was protected by a plastic shelter with special heating.
The are two large plants of this cycad in the Tropical Ravine. One is a female and produced a huge seed cone in 2017. Unfortunately there was no pollen-bearing male plant nearby so the seeds were not viable. One of the plants lost all its leaves during the building work and looked dead. It has completely revived and now has a crown of fresh bright green leaves.