Aneura marianensis sp. nov. (Hepaticae) of the Northern Mariana Islands

Aneura marianensis Furuki (Hepaticae; Aneuraceae) is described as a new species from the Northern Mariana Islands. The Northern Mariana Islands are part of the IzuMariana Archipelago, a chain of islands extending from temperate to tropical zones. The Northern Marianas have many endemic species, but the area remains poorly studied. A biological research expedition to this archipelago was conducted in 1992. I participated in it and made a field survey of the bryophytes. Among the bryophytes collected I recognized a new species of Aneura. ANEURA MARIANENSIS Furuki sp. nov. (FIG. 1-11) Affinis Aneurae blasioidi (Horik.) Furuki, sed differt thallis marginibus dentatis. TYPE: NORTHERN MARIANA ISLAND ALAMAGAN ISLAND. On west-facing slope, on soil in grassland, 500 m alt. , with Riccardia graeffei, Furuki 10980 (holotype, CBM, = herbarium of the Natural History Museum and Institute, Chiba). Thalli medium-sized, prostrate, deep green when fresh, whitish brown in herbarium, mammillose on surface, emarginate to bifid at apices, dentate and weakly plicate to undulate along margins, sparingly branched; cross section convex above and concave below, linear, 6-10 cells (250-350 Itm) thick, winged (unistratose alar portion 4-7 cells wide) at margin; epidermal and marginal cells of thallus thin-walled, polyangular, 50-75 x 30-80 Am, 1/4-1/3 the inner cells in size; inner cells polyangular, 75-150 x 40-75 Am; oil bodies present in all cells of thallus, 15-30 per cell, translucent gray, globose to ovoid, 2.5-10 Am, with indistinct granules, usually aggregated at center of inner cells; mucilage hairs 4 rows on ventral surface of thallus, 50-75 ctm long, 20-25 tm thick; rhizoids scattered, restricted to less than 0.6 the ventral surface in width; gemmae unknown. Dioicous. Male branches irregular, sometimes similar to lateral vegetative branches; lateral wings obliquely spreading, 3-7 cells wide, 25-400 Ctm high; antheridial chamber irregular, 2 to many rows, aperture 100-200 tm diam. , 2-3 cells between apertures; female branches short, lateral on main axis; paraphyses hair-like to clavate, to 400-700 tm high; calyptrae massive, smooth. Sporophytes not observed. PARATYPES: NORTHERN MARIANA ISLANDS. ALA AGAN ISLAND. On west-facing slope, ca. 500 alt. , on oil in grassland, Furuki 10604, 10991 (cBM). The distinguishing characters of Aneura marianensis are 1) dentate margin of thallus, 2) wide unistratose wing of thallus, 3) mammillose dorsal surface of thallus, 4) wide irregular male branches, and 5) short female branches. Aneura marianensis Furuki is very closely allied to A. blasioides (Horik.) Furuki in having a mammillose dorsal thallus surface and irregular male branches, but this new present species is clearly distinguished from the latter by the dentate margin of its thallus. The margin of A. blasioides is entire, but near female branches it sometimes tends to be denticulate. A denticulate margin near female branches is often observed in some species of Aneura; however, the denticulation throughout the margin of the thallus is unique to A. marianensis. The unistratose wing of the thallus is more than 4 cells wide in A. marianensis, but that of A. blasioides is less than 3 cells (Furuki 1991). The wide unistratose wing is similar to that of A. maxima, but A. marianensis is 'This work is part of the results of a cooperative expedition to the Northern Mariana Islands supported by the Natural History Museum and Institute, Chiba, and the Division of Fish and Wildlife, Department of Natural Resources of the Commonwealth of the Northern Mariana Islands. 0007-2745/94/87-88$0.35/0 This content downloaded from 207.46. 13.11 on Mon, 17 Oct 2016 05:28:48 UTC All use subject to http://about.jstor. org/terms 88 THE BRYOLOGIST [VOL. 97