The Tropical Greenhouse, built in 1993 and renovated in 2009-2010 with the help of the Lazio Region, the Carivit Foundation and the University, extends for almost 200 m2, with a maximum height of 6 m. Inside, a warm and humid environment has been recreated, with temperatures never dropping below 15 ° C in winter and exceeding 32 ° C in summer. The humidity is constantly maintained between 80 and 85% also thanks to a misting system.
It houses a collection of plants coming mainly from the American and Asian continents to represent shapes and composition of tropical and equatorial environments. Orchids, bromeliads, cicadaceae, ferns, palms and ficus can be admired. Here we can also find some specimens of Nephentes L., a carnivorous plant that evolved structures in the shape of a calyx in order to capture insects (ascids).
Some small aquatic species, now naturalized in Italy, are cultivated inside small tanks; among these we find the fern Azolla filiculoides Lam., the water hyacinth Pontederia crassipes Mart. and the curious water lettuce Pistia stratootes L., occasionally present in Northern Italy.
In nature, most of the species of the genus Ficus grow in humid tropical forests, many other species are found in drier or sub-tropical ecosystems, scrub-forests, or as isolated trees in the savannahs. The genus Ficus L. has its diversity center in Asia and Australia. In addition to some well-known species, in the greenhouse we can find: Ficus lyrata Warb. F. pumila L., F. rubiginosa Desf. ex Vent, F. salicifolia Wahl. e F. umbonata Reinw.
The greenhouse houses some plants that humans have been using since ancient times; among others there are the pepper plant (Piper geniculatum Sw.), the banana tree (Musa basjoo Siebold & Zucc. ex Iinuma), the coffee (Coffea arabica L.). Numerous specimens of cotton (Gossypium herbaceum L.) are also present, producing fertile seeds; it is the most important textile plant in the world used by man.
Orchids are present in almost all the world, although they are mostly represented in the tropical or sub-tropical areas of Asia, Central America and South America; only 15% of them grow spontaneously in temperate and cold areas. The family is represented by about 800 genera and over 20,000 species, and only over 100 of them are in Italy. Most of the tropical species grow on tree trunks or on rocks, therefore they have aerial roots capable of absorbing from the water present in the environment those substances necessary for their survival. In the greenhouse they are mainly housed in a corner protected from direct sunlight, where we find Stanhopea tigrine Batem., Angraecum longicalcar (Bosser) Senghas and numerous specimens of Phalenopsis Blume.
Cicadaceae are a group of gymnosperms that retain, in their vegetative and reproductive organization, very archaic characteristics. Their evolutionary origin is located in the Carboniferous or at the beginning of the Permian Eras and they reached their maximum abundance and diffusion in the Mesozoic Era. They often have the appearance of palm trees, with an erect, columnar, and undivided stem and large, compound, leathery leaves with a pungent apex, all brought at the caule apex.
Currently the collection includes specimens of Dioon edule Lindl., Dioon spinulosum Dyer ex Eichler and Cycas rumphii Miq. Their distribution is linked to tropical and subtropical areas around the globe.
