Studies on Geocalycaceae XIV. <i>Physotheca</i> J. J. Engel &amp; Gradst., a new genus of Hepaticae from Ecuador, belonging to a new subfamily, Geocalycaceae subfam. Physothecoideae J. J. Engel &amp; Gradst.

Resumen

Physotheca autoica J. J. Engel &amp; Gradst. is a liverwort genus and species new to science and is endemic to the Andes of southern Ecuador. The new genus, while having several characters also found in the family Geocalycaceae, differs from members of that family in a number of important respects, which are discussed. The mode of growth of Physotheca is unusual, and occurs strictly by repeated innovations originating from below the bracts or bracteoles of the gynoecium. The inflated, bladder‐like perianths are noteworthy, and have a shape and form that is remarkably similar to the sterile perianths of the unrelated genus Pleurozia . Capsule wall anatomy is also unusual, the walls are 7–8‐stratose, and the outer layer, which has both one‐phase and two‐phase development represented, readily collapses. The large spores (to nearly 39 µm) are echinate and nearly three times the elater width, and the elaters, which frequently uncoil, adhere in considerable number to the inner face of the capsule wall. The best placement of Physotheca is within the family Geocalycaceae. Due to the unusual combination of these and other characters, the genus does not fit into any of the known subfamilies of Geocalycaceae and must be placed in a new subfamily, Physothecoideae J.J. Engel &amp; Gradst.