The Monumental Greenhouse is one of the most prominent and majestic structures within the Botanical Garden.
Its masonry structure, abutting the northern part of the perimeter wall, is centered with the main entrance of the garden. Its construction work began in 1808 and was completed around 1820. Initially known as the "Temperate House," the Monumental Greenhouse is designed in a neoclassical style, inspired by the 18th-century "Orangeries" that housed citrus trees during unfavorable seasons in countries with harsh climates. This rectangular building measures 48 m in length and 11 m in width. Its façade features fluted Doric columns, separated by seven arches. These arches are covered with glass panels supported by wooden frames that rotate around a central pivot. At the top of the façade, 30 metopes depict some of the species cultivated in the garden in the early 19th century. The greenhouse is dedicated to Professor Aldo Merola, Director of the Botanical Garden from 1963 to 1980.
The Monumental Greenhouse houses a wide and diverse collection of potted plants, including species from various plant families. Upon entering through the enormous monumental doors, visitors find themselves surrounded by young specimens of Baobab (genus Adansonia), which can reach considerable sizes in their natural habitat and are symbolic of the African continent. Moving among the fronds of various palms, one can catch the scent of the fragrant and pure-white flowers of Acokanthera, a poisonous species whose sap was traditionally used by indigenous people to poison the tips of their arrows.
The collection in the Merola Greenhouse has grown over the course of two centuries through the botanical expeditions of Neapolitan botanists, making it a true dream for students entering the fields of Natural History and Biological Sciences.
During the summer, the greenhouse hosts scientific and cultural events.