Part 2. Introduction to Mitthyridium

Mitthyridium is a monophyletic member of the tropical moss family Calymperaceae (La Farge et al., 2000; Wheeler et al., in press) and is itself composed of approximately 12 monophyletic groups (junquilianum, subluteum, perundulatum, luteum, undulatum, fasciculatum, repens, papuanum, leucoloma, obtusifolium, constrictum, and crassum). Mitthyridium is found only in the paleotropics, from eastern Africa to Tahiti (see range map below), is most diverse in the Malay Peninsula and appears to have spread across both the paleotropical Pacific and Indian Oceans from this center of diversity. A previous paper established as the best outgroup candidate for Mitthyridium, the paleotropical taxon Syrropodon mahensis (Wall, chp1).

Mitthyridium is distinguishable morphologically from its relatives in Calymperaceae by its leaf margins, which consist of multiple rows of clear, dead, elongated cells, and also by its spreading style of growth, cladocarpy. Mitthyridium is dioicous bearing male and female gametangia on separate plants, and has a range of reproductive strategies, from purely vegetative, to asexual and bearing leaf propagules (gemmae), to fully sexual and producing diploid sporophytes.

Recent studies have shown that Mitthyridium is a young lineage (no more than 8 million years old) and is in the process of very rapid diversification that may in part be driven by its variable reproductive life history strategies. Mitthyridium has evolved and likely continues to evolve at a rate comparable to the most impressive examples of "adaptive radiation" now known, including the Hawaiin silverwords and Neogene horses. The study is the first moss radiation ever reported (Wall, chapter 2). Navigate the PHYLOGENETIC MONOGRAPH site further and feel the power of this impressive moss.