Evaluation of pollen morphology as a taxonomic character for generic delimitation in Scilla s.l. (Hyacinthaceae)

Abstract

Scilla L. s.l. (Hyacinthaceae) comprises about 100 species distributed in south Europe, the Mediterranean region, and central and western Asia with 10 species reported from Iran.However, according to recent studies based on molecular data Scilla s.l. is not monophyletic and should be divided into several smaller genera, i.e. Fessia Speta, Othocallis Salisb., Pfosseria Speta, Prospero Salisb., Scilla s.s. and Zagrosia Speta.In the present study the pollen grains of 13 species representing six segregate genera within Scilla s.l. were studied to evaluate the taxonomic value of pollen characters for generic delimitation. Pollen grains of all examined species were found to be monosulcate, prolate or sub‐prolate and heteropolar. Three different types of exine sculpturing were recognized: fossulate, perforate–reticulate and perforate.In Prospero autumnale (=Scilla autumnalis) pollen exine sculpturing is fossulate. In Othocallis armena, O. mischtschenkoana, O. rosenii and O. siberica (=Scilla armena, S. mischtschenkoana, S. rosenii and S. siberica) exine sculpturing is perforate–reticulate with mainly large perforations surrounded by smaller ones. In Fessia gorganica, F. greilhuberi, F. hohenakeri, F. khorassanica and F. raewskiana (=S. gorganica, S. greilhuberi, S. hohenakeri, S. khorassanica and S. raewskiana) the exine is perforate with rather uniform perforation. Zagrosia persica (=S. persica) has the same exine type as Fessia spp. In Pfosseria, the exine is perforate with linear and circular perforations. Scilla s.s. has a perforate exine, but the perforations are not uniform and their size and shape are variable.Our results are generally congruent with the circumscription of the new genera previously included in Scilla s.l. and show that pollen exine morphology is useful as an additional taxonomic character for the delimitation these segregate genera.