These two old iron structures date back to the second half of the 19^th century. They were originally a hothouse and a greenhouse where warm-weather species could be acclimatised. The specimens were first placed in the hothouse (the larger of the two buildings), which had a heating system comprising a boiler and pipes which ran through the area in which the plants were kept. They were then transferred to the greenhouse, which was warmed by the sun alone; here, without artificial heating, they gradually adapted to the local climate before finally being planted outside.