Succubous

Abstract: Bragginsella gen. n., with only B. anomala sp. n., is known only from plants collected in Arthur's Pass National Park, South Island, New Zealand. Known only from sterile plants, the familial position remains uncertain, although with the aspect of the Jungermanniaceae. It differs from genera of that group in a) transverse or feebly incubous dorsal leaf insertion; b) sporadically discernible, few-celled, bifid underleaves with slime papillae; and c) peculiarly armed leaves, with hyaline, dome-shaped "papillae" produced over intersection points where walls of the cells join. Although tentatively placed in Jungermanniaceae subf. Jungermannioideae, this disposition is based as much on ignorance as conviction. The Jungermanniaceae s. lat. (sensu Schuster 1970) include several subfamilies in which the alternate leaves are usually unlobed. In nearly all of these subfamilies, genera have leaves that are strongly obliquely succubously inserted (e.g., in Schuster [1969], NardiaFigs. 259: 9 and 263: 5, 11; Cryptocolea-Fig. 269: 1; Jungermannia [Solenostoma subg. Luridae]-Figs. 273: 2,4,5; Solenostoma subg. Solenostoma-Figs. 283: 4 and 284: 1-3; Solenostoma subg. Plectocolea-Figs. 287: 1,2, 289: 1,2, 293: 11; and Mylia-Fig. 298: 10). Only in androecia, and sometimes in and near gynoecia, does the leaf insertion become almost transverse and the concavity of the leaf or leaf base is turned toward the shoot apex. The succubous insertion and orientation give these plants a considerable degree of uniformity. The following plant, described below as Bragginsella, departs considerably from other Jungermannioids in aspect because leaf insertion is almost transverse dorsally on sterile shoots, with the dorsal insertion line inclined a little toward the shoot apex. The type material, collected at Arthur's Pass, New Zealand on Feb. 2, 1984, was, unfortunately, not studied while still alive and no data are available on oil bodies. Preliminary studies (FebruaryMarch, 1984), while I was at the University of Otago, suggested that some "strange" Jungermannioid was at hand. The specimen was studied repeatedly in the intervening decade, each time with no resolution as to the identity of the plant. In March 1995, collections were made again, with J. J. Engel, at Arthur's Pass; but no additional material was seen. In attempting completion of Vol. II of a projected "Hepaticae of New Zealand", the plant was studied for a fourth or fifth time. I reluctantly concluded that an unknown genus, presumably of Jungermanniaceae, was at hand. Since the plants are sparing and sterile, I have resisted describing this taxon for over a decade, but we need a name for this plant and the accompanying diagnosis and figures should allow its recognition. In general, I remain uneasy about describing a new genus from sterile plants, and I remain equally uneasy about assigning the genus to the Jungermanniaceae. It is tentatively placed there only because I do not know where else to place it. Bragginsella has a uniquely adorned leaf, covered with hemispheric or domelike tumidities ("papillae" is scarcely a suitable term, but is used for want of a better term). In the unlobed, alternate leaves, and scattered rhizoids-and the lateral-intercalary branching-it is similar to the Jungermannioideae. Yet cytological features and the manner in which the leaves are inserted and oriented convey a nagging feeling that these general-"generic" in one sense-similarities are not due to a common evolutionary history, but represent homoplasies. The form of the vestigial underleaves reinforce these reservations. Until fertile plants are found, these conjectures remain exactly that: unprovable assumptions. The questions in my mind reside around the form, orientation, and peculiar patterns of coalescence of the "papillae" of the leaves (Fig. 2: 3). In m st Jungermannioids, when cells are papillose, they each bear many small papillae or verrucae that arise over the lumen as seen in Schuster (1969) in Solenostoma crenuliformis (Aust.) Steph. (Fig. 271: 5), S. obovatum (Nees) Schuster. (Fig. 291: 5), and Liochl ena lanceolata Nees (Fig. 257: 5). These "papillae" tend to be elongated along the long axis of the leaf and become "converted" to striolations in median and/or basal cells of the leaf, as clearly shown in Figure 257: 5 of Schuster (1969). By contrast, the surface ornamentation in Bragginsella is, in my experience, unique in the Jungermanniales, but it is easily visible only on material that is 0007-2745/97/362-367$0.75/0 This content downloaded from 207.46.13.128 on Tue, 06 Sep 2016 05:44:10 UTC All use subject to http://about.jstor.org/terms 1997] SCHUSTER: BRAGGINSELLA GEN. N. 363 cleared (as in Hoyer's Fluid). On leaf margins one sees "crenulations" formed by what seem to be the dilated ends of radial walls of marginal cells. When the abaxial leaf surface is studied, a more complex situation is evident. These dilations are actually dome-shaped projections of wall material and immediately within the marginal cells it is evident that these "domes" arise over the points where radial cell walls intersect. In the distal fourth or less of the leaf these hemispheric (sometimes higher than hemispheric) domes lie juxtaposed or often coalesce in transverse lines. Proximal to the apical area, the domes tend to coalesce in both transverse and longitudinal lines, with the result that, locally, 4-rayed "holes" delimited by four coalescent "domes", seem to occur, situated over the cell lumen. From the leaf middle to the base, the coalescence of the "domes" is principally in longitudinal lines, although some transverse coalescence remains (Fig. 2: 3), so that irregularly shaped but prevailingly longitudinal "thin areas" occur between the coalesced "papillae." At the leaf base these coalesced domes form prominent, irregular welts which seem to stop rather abruptly at the stem junc-