A description of Suhr's types of Callithamnion variegatum, C. striatulum and C. stuposum (Ceramiales, Rhodophyta) in KIEL
The types of Callithamnion variegatum Suhr, Callithamnion striatulum Suhr, and Callithamnion stuposum Suhr are re-examined. It is shown that Callithamnion variegatum exhibits one to four simple (rarely subdichotomously) divided whorl-branches from each axial cell, periaxial cells that are smaller, similar or larger than contiguous branch cells, gland cells touching with their greatest part the mother cell, abruptly expanding axial cells along the apex, and rhizoidal cells provided distally with 'papilliform' cells. It is suggested that the species belongs to Antithamnionella Lyle, being most related to Antithamnionella verticillata (Suhr) Lyle. Callithamnion striatulum appears to be a distinct callithamnioid species. It exhibits cortication and lateral ramification with branchlets borne at a wide angle and tapering abruptly to small cells. The presence of terminal spine cells in Callithamnion stuposum Suhr, reported in later accounts but not in the protologue, is confirmed.