The 'Sagamihara Dome' conservatory of the Kitasato University Bio-Garden (北里大学薬学部附属薬用植物園 ドーム温室)

The Kitasato medicinal plant garden goes back to July 1965, when a first garden was opened at the university's practice station in Nihonmatsu (Fukushima), with a commemorative planting of red and white dogwoods, followed by phellodendron and rhubarb plants; the bark of the phellodendrons was gathered every year for pharmacognosy practicals. In 1972, on the occasion of the creation of the faculty's doctoral course, the garden restarted on the Sagamihara campus as a facility attached to the university, becoming a faculty facility in 1977; the Nihonmatsu garden closed in 1985.

The Sagamihara garden was then redesigned. A general-education building was erected within its grounds in 1988, then the 'Crescent' building (then the university restaurant) in March 1992, and the original layout changed profoundly. The university then reorganized the former greenhouse and the collection beds in harmony with these buildings and, in September 1992, the garden was renamed BIO-GARDEN with the completion of the dome. According to the university, this dome, nicknamed the 'Sagamihara Dome', is its centre and gives concrete form to the personal concept of the garden's director of the time. Later, the campus redevelopment (tied to the construction of a new university hospital) converted about a fifth of the Bio-Garden, its tree section of about 1,000 m², into a car park; a 1,400 m² trial field was recreated on a sports ground in March 2010.

The university describes the Sagamihara Dome as a greenhouse of 'characteristic structure', developed through 360°: sunlight enters it freely, and a system regulating lighting, temperature and watering had been installed to grow tropical and subtropical plants efficiently. The photograph in the garden's official leaflet, captioned 'overall view of the dome greenhouse', shows a dome with radiating ribs finely divided into transparent panels, crowned by a small lantern, resting on a low drum whose glass walls alternate with white piers; a glazed door stands at the centre of the front, facing a brick forecourt with a large flowering urn.

The circular footprint mapped on OpenStreetMap, about 170 m², is equivalent to a diameter of around fifteen metres; it coincides with the pale cupola visible on the aerial photograph of the Geospatial Information Authority of Japan. The garden's official plan draws the dome as a circle divided by radiating lines, next to the beds of herbaceous medicinal plants and the poisonous-plant area.

The dome gathers about 200 tropical and subtropical species, out of the garden's roughly 900. The garden director's welcome message points to two rarities there. The first is guarana (Paullinia cupana), a South American plant famous for seeds with five times the caffeine of coffee; he believes the plant exists only in Kitasato's dome, where it has flowered two years running. The second is jaborandi (Pilocarpus microphyllus), a rare plant that yields the pilocarpine used against glaucoma; it grows vigorously there and flowers every year.

Outdoors, the Bio-Garden shows in particular the source plants of the drugs of the Japanese Pharmacopoeia: fennel (Foeniculum vulgare), Baikal skullcap (Scutellaria baicalensis), Japanese goldthread (Coptis japonica), balloon flower (Platycodon grandiflorus), safflower (Carthamus tinctorius), tree peony (Paeonia suffruticosa), saffron (Crocus sativus) and chilli pepper (Capsicum annuum). It also has a rock garden, an area of medicinal fruit trees, poisonous plants, plants of the Man'yōshū anthology and aquatic plants. The journal of the Japan Medical Herb Association (Medical Herb, 2020) places peak flowering between March and May and names for that period Thunberg's fritillary (Fritillaria thunbergii), bay laurel, Japanese cornel (Cornus officinalis) and peony.

The dome stands at the heart of the Bio-Garden, on the Sagamihara campus, next to the 'Crescent' building. Admission is free; the university asks visitors not to come by car, as there is no parking, and to telephone before a group visit. The dome closes on Sundays and public holidays, while the garden stays open every day except university holidays. From March to May the outdoor plants are at their best.

The university cites Kanagawa Prefectural Sagamihara Park among the public facilities near the campus; the Sakata Seed greenhouse in Sagamihara Park, about a kilometre away, is also in this catalogue.