Reference

S. D'Emerico, Domenico Pignone, Pasqua Bianco (1996): Karyomorphological analyses and heterochromatin characteristics disclose phyletic relationships among 2n = 32 and 2n = 36 species of Orchis (Orchidaceae) – Österreichische Botanische Zeitschrift = Plant Systematics and Evolution – 200: 111 - 124.