INVESTIGATIONS ON A MONOTYPICAL GENUS: PENTAPLEURA HAND.-MAZZ. (LAMIACEAE)

The genus Pentapleura Hand.-Mazz. (Lamiaceae) is represented by only one species Pentapleura subulifera Hand.-Mazz and distributed in southeast of Turkey and north Iraq. The stem and leaf of the species were examined for anatomical studies. The stems are rectangular in shape and the leaves are equifacial type. The micromorphologic properties of trichomes, nutlets and pollens were described. Trichomes can be divided into two types as nonglandular and glandular. Also, glandular trichomes are of two types as peltate and capitate type. The capitate trichomes are divided into four subtypes. The nutlets are obovoid shaped and they have the prominent undulate-ridged ornamentation. The pollen grains of the species are hexacolpate, suboblate to subprolate in shape and they have perforated and microreticulate exine ornamentation. Introduction The genus Pentapleura Hand.-Mazz. (Lamiaceae, Nepetoideae), represented by only one species, Pentapleura subulifera Hand.-Mazz. is distributed in southeast of Turkey and northern Iraq (Handel-Mazzetti 1913, Davis et al. 1982, Harley et al. 2004). There is a study on the chemical characteristics of the species in Turkey by Başer et al. (2005), however, there has been no comprehensive investigation involving different aspects of P. subulifera as yet. Moon et al. (2008) investigated pollen of the two other subtribes Salviinae and Nepetinae, on the systematic significance of pollen characters in tribe Mentheae. Also a comparative micromorphological study of leaves was carried out on 102 species of Mentheae where 61 species were selected for the anatomical study by Moon et al. (2009). Trichomes morphology can be meaningful regarding the systematic relationships among the species of Lamiaceae (Özkan 2008). The morphology, distribution and frequency of glandular trichomes are used as determinative characters at sub-family level in Lamiaceae (Ascensão et al. 1995). The importance of scanning electron microscopy (SEM) for the study of nutlet surfaces and the taxonomic value of nutlet characters has been described for many genera of Lamiaceae (Husain et al. 1990, Demissew and Harley 1992, Marin et al. 1996, Budantsev and Lobova 1997, Jamzad et al. 2000). Until now, the anatomical, palynological and nutlet characters of P. subulifera have not been studied. Also, some characters including indumentum of leaves, calyx and corolla and nutlets, were not included in Flora of Turkey. This study was undertaken to find out important anatomical and palynological characters which play an important role in the taxonomy of P. subulifera. Author for correspondence. . Department of Pharmaceutical Botany, Faculty of Pharmacy, Anadolu University, Eskişehir 26470, Turkey. Department of Biology Education, Faculty of Necatibey Education, Balıkesir University, Balıkesir 10100, Turkey.