High altitude areas on Psiloritis are covered by phryganic vegetation, with a predominance of characteristic “pillow” shaped dwarf shrubs. Trees are scarce due to intensive grazing and high altitudes. Kermes Oak (Quercus coccifera) and Cretan Maple (Acer sempervirens) are the dominant trees. Oaks are very common as bushes, or “katsoprinia” (the overgrazed dwarf form), or even as bigger trees (when they have managed to escape grazing). Greek Spiny Spurges (Euphorbia acanthothamnos), Narrow-leaved milk-vetch (Astragalus angustifolius), Cretan milk-vetch (Astracantha cretica), are all cushion-like dwarf shrubs on the high altitude plateaus of Psiloritis, while Cretan Barberry (Berberis cretica) forms slightly taller bushes. In the lowlands Kermes Oak, Cretan Maple and Cypresses form small forests such as in the Rouvas or Arkadi area, while agricultural activities related to olive trees occur.
Many phryganic and annuals of Psiloritis are endemic to Crete, and indeed some are found only on Psiloritis (stenoendemic). Horstrissea dolinicola (one of the four endemic genera of Greece) grows only in small plateaus around Skinakas. Tulipa doerfleri, Crocus oreocreticus and Pοlygonum idaeum, are all Cretan endemics common on the Nida plateau. In many places different orchid species occur, the most important of them, the Cretan Cephalanthera (Cephalanthera cuculata) which is a vulnerable species, occurring in the mountain areas of Gergeri and Kamares. The aromatic and pharmaceutical plants of the park are also well known, such as Cretan Dittany or “erontas” (Origanum dictamnus).
Further information in the site : www.psiloritis.eu