Recent Topics Posters
Barbara Crandall-Stotler, Joshua Salter, Raymond E. Stotler.
Gynoecial organization and sporophyte anatomy of Herzogianthus R. M. Schust., a rare New Zealand liverwort.
Herzogianthus, erected to accommodate the morphologically unique Blepharostoma vaginatus, currently comprises 2 species, H. vaginatus, endemic to North Island and H. sanguineus, known only from South Island. Until recently the genus was aligned with Chaetophyllopsis, an Australian taxon with a somewhat similar facies, in the suborder Ptilidiineae. Multilocus molecular analyses do not support this alignment and instead resolve Herzogianthus as an isolated lineage that is close to but not included in the Ptilidiineae clade, without resolving unambiguously the backbone positions of either clade. To provide further insight into the affinities of this taxon, we have studied its gynoecial and sporophyte organization, using a combination of serial sectioning and SEM techniques. Gynoecia terminate main stems, but appear lateral because of the growth of innovations. Twelve to 16 very long, stalked archegonia are surrounded by a short perianth and several series of ensheathing, fused bracts and bracteoles. With development of the sporophyte, stem cells beneath the sporophyte and at the base of the perianth divide so that the mature sporophyte is encased by a thin shoot calyptra and thick, multistratose "perianth" that structurally resembles the stem perigynium of Isotachis. The sporophyte foot is completely embedded in the stem and is conical in outline, with a broad collar. The seta is large and of the general type. The capsule is short cylindric, with a 5- to 6-stratose wall, spores are large and densely verrucate, and elaters are unbranched and bispiral throughout. Both gynoecial organization and sporophyte anatomy support a relationship between Herzogianthus and Ptilidium and suggest a closer affinity of these lineages to the Jungermanniales than to the Porellales.