A morphometric and taxonomic study of Anthurium augustinum complex (Araceae), endemic to the Brazilian Atlantic Forest

Abstract

The Anthurium augustinum (Araceae) complex (including A. augustinum K. Koch & Lauche, A. hatschbachii E. G. Gonç., A. jureianum Cath. & Olaio, A. laucheanum K. Koch, A. lhotzkyanum Schott, A. lucidum Kunth, A. maximiliani Schott and A. parvum N.E.Br.) is endemic to the Brazilian Atlantic Forest. Some of these taxa are strictly endemic, with only the type population known, and may occur in sympatry. These species share a leaf morphology in which the blade is deflexed at the petiole insertion and is usually cordate, or rarely rounded at the base due to congenital fusion of the basal lobes. Taxonomic delimitation of the species in this group is difficult because of overlap in diagnostic characters such as deflexed leaf blade, cordate, rounded or semi-oval leaf base and camptodromous venation. The objective of the study was to test whether these taxa could be recognized using leaf morphometrics. Elliptic Fourier analysis was carried out on a sample of 257 individuals in 12 natural populations. The results of multivariate analyses indicated that in various comparisons, leaf shape was not diagnostic due overlap of variation within and between populations of different species. Consequently, we propose that A. laucheanum, A. lhotzkyanum and A. maximiliani should be regarded as synonyms of A. augustinum, and that the following five species be recognized in this complex: A. augustinum, A. hatschbachii, A. jureianum, A. lucidum and A. parvum. We also formally designate two neotypes (A. laucheanum, A. maximiliani), one lectotype (A. augustinum) and one epitype (A. augustinum).