Austral Hepaticae. 28. Plagiochila bazzanioides Engel & MerTill, a Remarkable New Species of Plagiochilaceae from New Zealand John J. Engel and G. L. Smith Merrill Department of Botany, The Field Museum, Chicago, Illinois 60605-2496, U.S.A.ABSTtnCTr. Plagiochila bazzanioides, a new spe-cies from New Zealand, is described and illustrat-ed. Plagiochila is the largest genus of hepatics, withperhaps as many as 1600 described species (Bon-ner, 1962). As in other species-rich groups, the ac-tual number of species will probably prove to beconsiderably less. According to Schuster (1980:348), "The total number of valid species of Plagi-ochila may prove to be below 500." The genus iswidely distributed and essentially cosmopolitan.Centers of taxic diversity are chiefly in the Neo-tropics and southeast Asia, and the genus is ratherpoorly represented in temperate areas. For exam-ple, Schuster (1980) included 20 species for NorthAmerica, and Inoue and Schuster (1971) included25 species from temperate Australasia. This paperdescribes an additional distinctive species occur-ring in New Zealand, as follows.Plagiochila bazzanioides Engel & Merrill, sp. nov. TYPE: New Zealand. North Island: North Auckland Province, Rangitoto Island, imme-diately E of Auckland, 50-160 m, 4 Feb. 1995, Engel 20769 (holotype, F; isotype, CHR). Figure 1. Species insignis filiis falc lis canaliculatis dlecurvatis.niarginis foliorii pc tlinatis dIlenibius gracililt s unciiiatis,raiis plurimis flagelliforminits, aiiroeciis inlcrcalaribus.piraplhylliis caulis dcntalis laim lliformibius a species nob-is notis optime d(islincla. Plants bazzanioid in habit, ascending, withoutdifferentiation of a horizontal leafless axis, rich,deep olive green; leafy shoots medium, to 5 mmwide. Stems with paraphyllia inconsplicuous, typi-cally consisting of a single, short, sharply toothedlamella adjacent to dorsal leaf base; stem in crosssection with cortical cells in (2)3 layers of verythick-walled cells, the medullary cell walls thin,colorless. Branching exclusively lateral-intercalary,sometimes with geotropic, microphyllous. rhizoi-dous, flagelliform, lateral-intercalary branches.Rhizoids rather dense on leafy shoots. Leaves hor-izontally spreading to ventrally secund, often con-spicuously falcate, spreading at -right angles tostem, closely imbricate, frequently canaliculate-subtubular to the tips, the dorsal margins narrowlyrecurved and forming a distinct convex fold, lend-ing the shoot a tightly pleated aspect in dorsal view,in ventral aspect the ventral margin aligned at rightangles to the stem except for the basal sector, whichlies parallel to the stem, in ventral view the ventralmargins pectinate-toothed, the teeth often stiffly re-flexed and hooked dorsally, the ventral surface ofstem moderately or totally hidden; leaf insertionelongated, distinctly straight and steeply obliquefor most of its length, abruptly recurved at ventralend; leaves asymmetrically narrowly elongate-trap-ezoidal, tapering to a markedly narrow, almost par-allel-sided distal 0.2 to 0.3; leaf apex narrowlyrounded to truncate, tending to become bidentateby 2 conspicuous, often diverging apical teeth thatare often larger than adjacent teeth; dorsal marginnearly straight to broadly curved inward, with +regularly spaced, slender, recurved teeth to thebase (best seen in ventral aspect); ventral margin+ straight from a subauriculate base, conspicuous-ly ciliate-dentate particularly in basal portion, theteeth stiffly reflexed (hooked dorsally), the marginoften entire or subentire in the distal 0.5. decur-rent, the decurrent strip dentate. Marginal teethslenderly acuminate, 1-2 cells wide at the base,consisting almost entirely of a uniseriate row of i4-6 distinctly thick-walled cells, the terminal cellelongate, to 4.2:1. Underleaves consisting of anamorphous clump of cells, in part short-filamen-tous, at end of decurrent ventral leaf base. Cells inmedian portion of leaf thin-walled and with trigonesbulging to knotlike; median cells 20-29 Lpm wideX 30-36 pm long; cells of leaf bases scarcely elon-gated and not forming a basal field; cuticle smooth.Asexual reproduction lacking. d Plants � smaller than the Y ones, mostly sim-ple; androecia on main shoot and leading lateral-intercalary branches, becoming intercalary in posi-tion (often with several successive androeciaoccurring on a stem or branch); bracts many, in upto 15 pairs, strongly saccate in dorsal half of base;apex broadly rounded, spatulate, entire; ventral mar-Nov'o, 9: 29-31. 1999.
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