Macromitrium brachypodium Mull. Hal.

Macromitrium brachypodium Müll.Hal. Botanische Zeitung (Berlin) 15: 778 (1857). TYPE. — New Caledonia. “Île des Pins”, Cuming s.n. (lecto-, H-BR [designated by Vitt & Ramsay, 1985]; isolecto-, PC [PC 0096548]!). ILLUSTRATIONS AND DESCRIPTION. — Vitt & Ramsay (1985a). DISTRIBUTION IN NEW CALEDONIA. — Macromitrium brachypodium is very rare, with only one report in South Province (type locality,Île des Pins) and one in North Province, in a very disturbed environment. Due to the scarcity of the data, its ecological range in New Caledonia remains unknown. TOTAL RANGE. — New Caledonia and Lord Howe Island. Its occurrence in mainland Australia must be confirmed according to Vitt & Ramsay (2006). SELECTED SPECIMEN. — New Caledonia. Province Nord, Koumac, Tiebaghi ultramafic massif, on bark in small remnant of the moist forest amongst scrubland, in the vicinity of a former mining village, 28.IX.2008, Thouvenot NC288 (PC). DESCRIPTION Pseudautoicous. Macromitrium brachypodium may be identified by: 1) small size of branches, less than 6 mm long, 0.8-1 mm wide; 2) branch leaves when dry erect to oblique, individually twisted, the incurved apices exposed by the margins, when wet patent to spreading, slightly sigmoid; 3) branch leaves 1.5-2.5 mm long, ligulate, obtuse to short acute, mucronate; 4) upper cells rounded, 6-8 µm, bulging, thick-walled, with c. 4 small rounded papillae; 5) basal part of leaves undifferentiated, with a few short rectangular lower cells, smooth; 6) perichaetial leaves longer than the vegetative ones, 3.5 mm long or more; 7) vaginulae naked; 8) calyptrae hairy; 9) setae very short, 1-1.5 mm long; and 10) capsules oblong, 1-1.3 mm long, smooth, rims erect, not plicate, peristomes single. It could be confused with other small species with little differentiated basal part. For differences with M. brevicaule and M. aurescens, see under the latter. Macromitrium francii and M. pilosum have longer branches, smaller leaves with papillose basal cells, vaginulae with conspicuous long hairs and capsule mouth plicate. In addition, Macromitrium orthostichum calyptrae have bristly hairs. See discussion in the paragraph dealing with the Francii group.短柄大帽藓（Macromitrium brachypodium Müll.Hal.） 发表文献：《柏林植物学杂志》（Botanische Zeitung (Berlin)）15卷：778页（1857年）。 【模式标本】——采自新喀里多尼亚"松岛（Île des Pins）"，Cuming无号标本（后选模式标本（lectotype）：H-BR，由Vitt与Ramsay于1985年指定；等后选模式标本（isolectotype）：PC [PC 0096548]！）。 【插图与描述】——参见Vitt与Ramsay（1985a）。 【新喀里多尼亚分布】——短柄大帽藓极为罕见，目前仅在南部省（模式产地松岛）及北部省各有1份记录，北部省标本采自受严重干扰的生境。因现有数据匮乏，其在新喀里多尼亚的生态幅尚不明确。 【总分布范围】——新喀里多尼亚与豪勋爵岛。根据Vitt与Ramsay（2006）的研究，其在澳大利亚本土的分布有待证实。 【选录凭证标本】——新喀里多尼亚，北部省库马克地区，铁巴吉超镁铁质地块，灌丛间残存湿润林的树皮上，毗邻废弃采矿村落，2008年9月28日，Thouvenot NC288（PC）。 【形态描述】 假雌雄同株。短柄大帽藓可通过以下特征鉴别：1）分枝小型，长不足6mm，宽0.8~1mm；2）干时枝叶直立至斜展，各自扭转，叶缘内卷使先端外露；湿时平展至开展，略呈S形弯曲；3）枝叶长1.5~2.5mm，舌形，先端钝至短尖，具小尖头；4）叶上部细胞圆形，直径6~8μm，强烈膨大，壁厚，具约4个小型圆形疣突；5）叶基部区域未分化，仅具少数短矩形下部细胞，表面平滑；6）雌苞叶长于营养叶，长可达3.5mm以上；7）蒴柄鞘无毛；8）蒴帽具毛；9）蒴柄极短，长1~1.5mm；10）蒴果长圆形，长1~1.3mm，表面平滑，蒴口直立，不具褶纹，蒴齿单层。 该种易与其他叶基部未分化的小型大帽藓属种类混淆。与短茎大帽藓（M. brevicaule）和金色大帽藓（M. aurescens）的鉴别特征参见后者的描述。 弗朗西大帽藓（M. francii）与多毛大帽藓（M. pilosum）具有更长的分枝，叶片更小且叶基部细胞具疣，蒴柄鞘具显著长柔毛，蒴口具褶纹。 此外，直叶大帽藓（M. orthostichum）的蒴帽具刚毛状毛茸。相关讨论参见弗朗西类群章节。