Contrary to other localities in the same highland, the Paramo de Sabanazos is relatively conserved and has an extensive area of trees, where the dominant element is Quercus humboldtii Bonpl. & Kunth. Frequently growing in association with P. roldanii, are other species like Aragoa occidentalis Pennell, Arcynophyllum nitidum (H. B. K.) Schlecht., Bartsia stricta (H. B. K.) Benth, Castratella pilloseloides (Bonpl.) Naudin, Espeletia occidentalis A. C. Smith ssp. antioquensis Cuatrec., Guzmania confinis L. B. Smith, Lysipomia muscoides Hook. f. and Palicourea aschersonianoides (Wernh.) Steyerm.
P. roldanii prospers in exposed places and has been for some time utilised by the bullfighting bovine livestock who frequently include in their diet the immature inflorescences of it. This previous activity made it difficult to find individual plants with inflorescences at anthesis, because on almost all previous expeditions the populations hardly had any inflorescences emerging or had been. Although P. roldanii is a small plant, its blue green flowers during the flowering time makes it stand out amongst the other herbaceous vegetation of the area. According to available herbarium registers the species flowers between the months of April and July.
HABITAT AND DISTRIBUTION: The type locality is in part of an extensive highland region in the extreme north of the Cordillera Central de Colombia, well-known as the Alti Plano de Santa Rosa de Osos. This highland is between 2400 and 3000 m, with slight and undulating slopes, of moderate to severe erosion; the soils have been developed from volcanic igneous and ashy rocks, they are deep, poor in nutrition and moderately evolutionary (Igac 1992). The region corresponds to a transition area among the zones of forest life in very humid low montane and the rainforest montane (bmh-MB and bp M), with annual average precipitation between 2000 and 2800 mm (Spinal 1985). —SeeBetancur & Callejas 1997
