Referring to a plant species, a paper I am reading (see citation below) says: "Blades are 4–5(6) mm long and (0.5)1–1.5 mm broad." I understand the numbers 4-5 and 1-1.5 would be the ranges, but what do the numbers 6 and 0.5 in the parentheses represent?
Domínguez, Y., Valdés, C. M. P., & de Miranda, V. F. O. (2012). New features of Cuban endemic Pinguicula filifolia (Lentibulariaceae) and considerations on its habitat and ecology. Flora-Morphology, Distribution, Functional Ecology of Plants, 207(11), 838-841.