Abstract
A floristic survey was implemented during 2021–2022 largely within Natura sites GR1430008 and GR1420004 in the Region of Thessaly, altogether comprising 796 km2. While both Natura sites were explored, the sampling effort was intensified within a narrow study area of 550 km2 encompassing the N part of Mt Pelion and the whole of Mt Mavrovouni. Sampling within the narrow study area was one-third guided by previous findings and two-thirds random. In total, 129 square cells 1 km2 wide were explored, of which 100 yielded orchid findings; 39 orchid taxa (species and subspecies) plus two nothotaxa were recorded. In the narrow study area, 33 orchid taxa and nothotaxa were recorded, of which 13 for the first time: Anacamptis papilionacea, A. pyramidalis, Himantoglossum robertianum, Ophrys × delphinensis, O. sicula, O. speculum, O. sphegodes subsp. sphegodes, O. tenthredinifera, O. tenthredinifera × O. sphegodes subsp. taurica (syn. O. mammosa), O. umbilicata, Orchis italica, O. simia, and Platanthera bifolia. The main threats facing orchids are rooting by feral pigs, overgrazing by ruminants, clearing of road verges, intensive arboriculture, and the encroachment of photovoltaic farms.