ANATOMICAL CHARACTERIZATION OF STACHYS MARITIMA GOUAN VEGETATIVE ORGANS

Abstract

Stachys maritima Gouan is a perennial herbaceous plant from the Lamiaceae family. It only grows on sand dunes, especially littoral ones. In Romania it is considered an endangered species, only found in few coastal areas of Tulcea and Constanța counties. Its vegetative organs (rhizome, aerial stem, leaf petiole and leaf blade) were harvested for anatomic analysis.
The rhizome showed a secondary structure, with thin suber, compact and thin phloem and compact xylem annual growth rings, while pith was mostly replaced by xylem elements. Aerial stems had the four-ridged shape common in many Lamiaceae, with caps of angular collenchyma protecting four major, semicircular, collateral vascular bundles. Multiple secondary bundles were also found, joined together by sclerified external pith layers. Leaf petiole was filled with undifferentiated parenchyma, made up of large polygonal cells, similar in shape to stem cortex and pith. Leaf blade had a weakly differentiated bifacial structure and was amphistomatic. Stems and leaves were covered by dense, massive, lignified tector hairs. Secretory hairs were small, exclusively peltate, mostly found on stems.