Structure and Development of Stomata in Some Labiatae

Abstract

The structure and ontogeny of stomata have been studied in 33 species of the Labiatae. The mature stomata are diacytic, transitional between paracytic and diacytic, and anomocytic. The anomocytic stomata are haplocheilic or perigenous. The diacytic and the transitional type of stomata are syndetocheilic or mesogenous as the two subsidiary cells and a pair of guard cells arise from the same meristemoid. The diacytic and the transitional stomata are formed through three successive mitotic divisions. Abnormal stomata with single guard cells, arrested developments, and contiguous stomata have been observed. Contiguous stomata are formed either from two adjacently placed meristemoids or are the result of spatial readjustment during maturation of the leaf.