This species of St. John's wort with a strictly Mediterranean distribution is present in all regions of Central, Southern and Insular Italy, except in the Marche. It grows in open woodlands, along hedgerows, sometimes in the gaps of the Mediterranean maquis, on soils which are dry in summer, from sea level to about 1200 m. The species is sporadic on the edge of the Sardinian temporary ponds , in contact with dry meadows and Mediterranean maquis. The genus name derives from the Greek 'hyper' (above) and 'eikon' (image, likeness), likely referring to the ancient custom of adorning the house with the flowers on the day of the Feast of Walpurgisnacht, later replaced by that of St. John (June 24th), an auspicious day to hang bunches of hypericum on the front door as protection from devils (also the common Italian name refers to that tradition); the species name refers to the sessile leaves that clasp the stem with the base. Flowering period: May to June.

Italian name(s): Erba di S. Giovanni a foglie cordate (Italia), Erba di San Giovanni a foglie cordate (Italia), Iperico perfogliato (Italia).