Nutlet morphology in the tribe Elsholtzieae (Lamiaceae)

Abstract

A comprehensive study on nutlet morphology on 46 taxa from the tribe Elsholtzieae was conducted using stereomicroscopy, light microscopy and scanning electron microscopy. The objectives were to evaluate the nutlet characteristics in a systematics context and to provide additional evidence for taxon delimitation. The nutlet shape varied from elliptical, widely elliptical, spheroidal and ovate to pyriform. The size ranged from 0.50 to 2.70 mm in length and 0.34 to 2.65 mm in width. The three types of trichomes included simple non‐glandular trichomes (Collinsonia punctata), clavate non‐glandular trichomes (Elsholtzia cephalantha) and peltate glandular trichomes (Mosla grosseserrata and M. chinensis). We also report the presence of a mucilaginous reaction in nine species of the genus Elsholtzia in Elsholtzieae for the first time. Four types (undulate, papillae‐like projection, thorn‐like pattern and reticulate) and three subtypes (reticulate, reticulate‐cellular and supra‐reticulate) of nutlet surface patterns in the mid‐ventral region were recognized in Elsholtzieae based on the differences in cell outline, outer periclinal walls and dentations of the anticlinal walls. These nutlet micromorphological results may serve as a reference for future hypotheses on the classification of the tribe Elsholtzieae.

Mosla dadoensis (Lamiaceae), a new species from the southern islands of South Korea

“…After a thorough literature survey and investigation of the relevant specimens, we designate M. dadoensis K.K.Jeong, M.J.Nam & H.J.Choi as a new species of Mosla from the southern islands of Korea. To clarify the systematic status of M. dadoensis we also conducted barcoding analysis based on nuclear ribosomal ( nr ) and chloroplast ( cp ) DNA regions, and observed detailed nutlet morphology, which is well known as a systematically important characteristic in Lamiaceae ( Moon et al 2009 ; Ryding 2010 ; Jeon et al 2020 ). A detailed morphological description of M. dadoensis and its geographical distribution is also provided.…”