CAPSULE, LEAF AND CYATHIAL GLAND MORPHOLOGY OF TURKISH PERENNIAL TAXA OF Euphorbia L. SECTION Pithyusa (Raf.) Lázaro

Ilker Genç,Gülay Ecevit-Genç,Şükran Kültür

doi:10.23902/trkjnat.342096

Ilker Genç, Gülay Ecevit-Genç + Show 1 more

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https://doi.org/10.23902/trkjnat.342096

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Abstract

Macro and micromorphology of cyathial glands, capsules and cauline leaf surfaces of 13 perennial species of Euphorbia L. subg. Esula Pers. sect. Pithyusa (Raf.) Lázaro in Turkey were studied. Cyathial gland structure, based on cyathial gland shapes, colour and appendages was examined from live material by direct field observations and investigations. Cauline leaves and capsule surface features were analysed with scanning electron microscopy (SEM). Capsule sizes, capsule shapes and capsule and cauline leaf surface ornamentations were also studied . The capsule shape was found to vary from subglobose to conical. In most species, cyathial gland colour ranged from greenish-yellow to yellowish-green but some species were distinguished by their reddish or purplish cyathial glands. Although the number of cyathial glands in all species was four, five cyathial glands were determined to exist in some specimens of E. pestalozzae Boiss. Three different cyathial gland shapes ( elliptic, trapezoid-elliptic or elliptic-reniform ) were observed. Capsule surface of more than half of the studied species (7 taxa) is covered with nipple-like projections (papillate-mammillate) and the rest are covered with tiny rounded or hillock-like ornamentation (colliculate). The cauline leaf surface is papillate-mammillate in the majority of the studied species, although, colliculate surface is also observed in two species ( E. seguieriana Necker and E. thessala (Form.) Degen & Dörf.). In conlusion, macro and micromorphological structures of cyathial gland and capsule of Euphorbia sect. Pithyusa taxa appeared to be useful diagnostic characters for species identifications.

Highlights

Euphorbia L. is one of the largest genera of flowering plants with more than 2000 species distributed throughout the world
We investigated the micromorphology of the cauline leaf surfaces after determining some variations on leaf surfaces of herbarium specimens included in the study
According to the result of this study, micromorphology of capsule surfaces is more useful as an identification character compared to the cauline leaf surfaces because the cauline leaf surface properties vary as the plant matures

Summary

Introduction

Euphorbia L. is one of the largest genera of flowering plants with more than 2000 species distributed throughout the world. Life forms within the genus vary from tiny annuals to perennial herbs and trees (Bruyns et al 2006, Horn et al 012). Genus Euphorbia is represented in Turkey by two subgenera Chamaesyce and Esula with a total of 120 taxa (Öztekin 2012, Genç & Kültür 2016). Subgenus Esula comprises about 490 species most of which are annual or perennial herbs mostly distributed in the temperate regions of the northern hemisphere in the Old World (Geltman 2015, Pahlevani et al 2017). Temperate Eurasia, the Mediterranean and the IranoTuranian regions are two most important diversity centres of Euphorbia subgenus Esula (Riina et al 2013)

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