Voortplantingswijze, hybridisatie en cytologie van het weidehavikskruid, Hieracium caespitosum Dumort

A clone of Hieracium caespitosum Dumort. was collected near Bunnik (province of Utrecht) and studied cytologically. The plants, which reproduce agamospermously, were characterized by the chromosome number 2n = 36 and belong tot subsp. caespitosum. Hybrids could be obtained between this subspecies and H. pilosella (2n = 36, 54) and H. lactucella (2n = 18). H. caespitosum was the pollen-donor in both cases.