Pit plugs and other ultrastructural features of systematic value in Rhodochaete parvula (Rhodophyta, Rhodochaetales)

Abstract

Rhodochaete parvula was considered to be unique among the red algae in having pit connections that are not occluded by pit plugs. Pit plugs, consisting only of cores, are now demonstrated to occur in this species. Plug caps and cap membranes were not found. Although more specialized than earlier thought, the condition found in Rhodochaete is likely to represent the ancestral character state of red algal pit plugs. Unlike most red algae, Golgi bodies in Rhodochaete are not closely and consistently associated with mitochondria. One or more peripheral, encircling thylakoids are present in the plastids, another condition likely to represent the ancestral condition of red algae.