Tropical Greenhouse (Serra tropicale), Angelo Rambelli Botanical Garden, University of Tuscia

The University of Tuscia's botanical garden, named after Angelo Rambelli, was established in 1985 and officially opened in 1991. It lies on the Viterbo plain below the Cimini hills, along Strada Santa Caterina. The whole site covers about fifteen hectares: six for the garden itself and nine for the Bulicame park, the source of a sulphurous thermal spring.

The tropical greenhouse was built in 1993, only two years after the opening, to give tropical forest plants a warm and humid shelter. It was refurbished in 2009-2010 with contributions from the Lazio Region, the Carivit Foundation and the university. The official website now lists further covered houses alongside it: the Astolfi greenhouse, a pteridophyte (fern) house, a tropical orchid house and a house called the 'Patriarchs of the Desert'.

Beyond display, the garden carries out teaching, research and educational work, biosystematic studies and acclimatisation trials. The tropical greenhouse serves as a living collection of plants from hot, humid regions, shown to students and the public alike.

The tropical greenhouse covers almost 200 m² and reaches a maximum height of 6 metres. Its equipment is designed to recreate a constantly warm and humid climate: the temperature never falls below 15 °C in winter or rises above 32 °C in summer, while a misting system keeps relative humidity between 80 and 85%. The same space also holds floating aquatic plants.

The 2009-2010 refurbishment concerned the 1993 building. It stands in a garden that makes use of the site's thermal resources: the nearby palm grove is warmed by thermal water flowing underground. Together with the Astolfi, pteridophyte, tropical orchid and 'Patriarchs of the Desert' houses, the tropical greenhouse forms a group of covered structures that complements the garden's open-air reconstructions, from an African oasis to a Mexican desert by way of Australian subtropical vegetation and Mediterranean scrub.

The collection brings together plants of tropical forests. Orchids are represented by Stanhopea tigrina, Angraecum longicalcar and Phalaenopsis; cycads by Dioon edule, Dioon spinulosum and Cycas rumphii. Several figs show the range of the genus Ficus: F. lyrata, F. pumila, F. rubiginosa, F. salicifolia and F. umbonata.

Floating aquatic plants - Azolla filiculoides, Pontederia crassipes and Pistia stratiotes - grow beside useful plants such as the pepper Piper geniculatum, the banana Musa basjoo, coffee (Coffea arabica) and cotton (Gossypium herbaceum). Nepenthes, carnivorous plants, complete the display. The garden's other houses extend the visit with ferns in the pteridophyte house, tropical orchids and frost-tender succulents including Kalanchoe and Euphorbia.

The garden lies in the Terme district of Viterbo, near the Bulicame spring, on Strada Santa Caterina. The tropical greenhouse is part of a route through the arboretum, the largest section, arranged by the geographical origin of the trees, the rose garden with some 200 species, the medicinal plant garden, the palm grove and the reconstructed natural habitats.

As a university garden it is mainly open on weekdays, and at weekends for events, so it is worth checking the calendar before going. Held between 15 and 32 °C, the greenhouse stays warm and humid all year round and can be visited in any season. A visit combines easily with Viterbo's historic centre.