Stomatal Structure Research Articles

The Stomatal Structure and Ontogeny in Azima and Salvadora

The ontogeny of stomata is described for threee species of the family Salvadoraceae. The mature stomata are anisocytic, paracytic, anomocytic, perigenous and with a single subsidiary cell. The development of anisocytic and paracytic types and those with a single subsidiary cell conforms to the syndetocheilic or mesogenous type. The ontogeny of anomocytic stomata is haplocheilic or perigenous. Sometimes in the anisocytic type, one of the subsidiary cells undergo tangential division and the mature stomata show 3—4 subsidiary cells. Abnormalities noticed here are (a) stomata with a single guard cell, (b) stomata with aborted guard cells and (c) stomata with unequal guard cells. Contiguously placed and group of stomata have been oberved.

THE TAXONOMIC SIGNIFICANCE OF CERTAIN ANATOMICAL OBSERVATIONS ON ERICACEAE

SummaryA review of the classical treatment of Ericaceae reveals how unconvincing are the usual definitions of the major groupings Ericoideae and Arbutoideae. However, a survey of stomatal structure, stomatal distribution and pith structure supports the taxonomic soundness of the main body of the Ericoideae, which are further characterized by their distinctive habit. Calluna is exceptional among Ericoideae in pith structure and stomatal distribution, and differs from the others in various aspects of gross morphology. There is a striking similarity between Calluna and Cassiope, a genus usually placed in the Arbutoideae; and there is little doubt that the two are closely related. These conclusions lead to speculation about the origin and development of the Ericoideae in the minds of taxonomists, and about the mechanism by which closely similar genera become separated at the level of sub‐family.