Taxonomic and nomenclatural rearrangement in the Hookeriales with notes on West Indian taxa

The Hookeriales are evaluated to discern familial limits. Five families are recognized in the order: Hookeriaceae, Leucomiaceae, Daltoniaceae, Callicostaceae, and Adelotheciaceae fam. nov. Chaetomitrium Dozy & Molk., Chaetomitriopsis. Fleisch., Dimorphocladon Dix., and Elharveya Crum are transferred to the Hypnaceae. Hookeriopsis (Besch.) Jaeg. is split into four genera: Hookeriopsis s. str., Brymela Crosby & Allen, Thamniopsis (Mitt.) Fleisch., and Trachyxiphium Buck, gen. nov. The following new combinations are proposed to coincide with the recognition of these four genera rather than Hookeriopsis s. lat.: Brymela acuminata, B. callicostelloides, B. cuspidata, B. fissidentoides, B. fluminensis, B. obtusifolia, B. parkeriana, B. rugulosa, B. websteri, Thamniopsis cheiloneura, T. cruegeriana, T. diffusa, T. incurva, T. langsdorffii, T. pappeana, T. purpureophylla, T. secunda, T. sinuata, T. terrestris, T. undata, T. utacamundiana, T. versicolor, Trachyxiphium aduncum, T. guadalupense, T. heteroicum, T. hypnaceum, T. pernutans, T. subfalcatum, T. tenue, T. vagum, and T. variable. Excluded species are treated as Isopterygium plumicaule, Schizomitrium cirrhosum, and S. subsecundum. Schizomitrium belangerianum (Besch.) Buck, comb. nov. is considered distinct from S. depressum (Hedw.) Buck & Steere, and S. pallidum (Hornsch.) Crum & Anders. is shown to have a smooth seta sometimes. The taxonomy of the aquatic species of Cyclodictyon Mitt. and Lepidopilum (Brid.) Brid. is clarified, resulting in the recognition of three species, Cyclodictyon subtortifolium (Bartr.) Buck, comb. nov., C. roridum (Hampe) Kuntze and L. tortifolium Mitt. Two new combinations are proposed in Calyptrochaeta Desv., C. setigera and C. albescens.