Plagiochila macrostachya Lindenb.

Plagiochila macrostachya Lindenb. (Fig. 11) Plagiochila macrostachya Lindenb., Species Hepathicarum (fasc. 2-4): 75 (1840). — Type: Jamaica. Hb. Hooker (lecto-, designated by Heinrichs [2002], W-Lindenb. 66). A D B F C G H E A D E B C H F I G Plagiochila granditexta Steph., Bulletin de l’Herbier Boissier (sér. 2) 4 (2): 165 (1904) syn. nov. — Type: Madagascar. Unknown locality, Hildebrandt s.n. (holo-, G00045478!). DISTRIBUTION AND HABITAT. — Peri-Afro-American: common throughout the mountains of tropical America (Heinrichs 2002), very rare in Madagascar; new to Africa. Previously recorded from La Réunion but the record belongs to P. boryana according to Grolle (1995). DESCRIPTION (see also Vanden Berghen 1981 as P. granditexta; Heinrichs 2002) Plants robust, c. 5 mm wide, vegetative branches scarce, all branches intercalary, rhizome-like creeping shoot present. Mature stem leaves loosely imbricate, widely spreading, subopposite, ovate-oblong to ovate-triangular, c. 1.5-2× longer than wide, widest at the base, ventral base with a high shoulder and ampliate on stem leaves, apex rounded, margins unbirdered, with (5-)10-18 coarse triangular teeth along the apical and ventral margin, the teeth (3-)4-8 cells long, 3-6 cells wide at the base, sometimes broken; dorsal and ventral bases rather shortly and narrowly decurrent, the opposite bases almost connate. Leaf cells somewhat elongate, large, 35-40 µm wide in midleaf, trigones medium-sized, triangular-radiate with concave sides, vitta-like area absent; cuticle smooth; oil bodies not observed. Underleaves absent. Male plants not seen. Female bracts larger and more coarsely toothed than vegetative leaves. Perianth (juvenile) without stalk, perianth mouth with numerous triangular teeth. Vegetative reproduction not observed. NOTES Plagiochila macrostachya (sect. Hylacoetis) is recognized by the robust plants (at least 5 mm wide) with intercalary branching, subopposite leaves with a shoulder and distinctly ampliate in basal stem leaves, triangular teeth, large leaf cells (35-40 µm wide in midleaf) and a smooth cuticle. The species resembles P. boryana in the large leaf cells but in the latter species the leaves are alternate, the teeth linear and the cuticle papillose. The plants from Madagascar were described by Stephani as P. granditexta Steph., which is identical to P. macrostachya in all respects. Vanden Berghen (1981) erroneously illustrated the leaves of P. granditexta as being alternate.大穗羽苔（Plagiochila macrostachya Lindenb.）（图11） 大穗羽苔（Plagiochila macrostachya Lindenb.），载于《苔类物种》（第2-4分册）：75（1840年）。——模式标本产地：牙买加，胡克标本馆（Hooker herbarium）藏后选模式标本（lectotype），由Heinrichs于2002年指定，馆藏号W-Lindenb. 66。 A D B F C G H E A D E B C H F I G 大纹羽苔（Plagiochila granditexta Steph.），载于《博西耶标本馆通报》（第2辑）4(2)：165（1904年），新异名（syn. nov.）。——模式标本产地：马达加斯加，无具体采集地，Hildebrandt无号标本（holotype，主模式标本），馆藏号G00045478！ 分布与栖息地。——环非美洲分布型：在热带美洲山地广泛分布（Heinrichs, 2002），在马达加斯加极为罕见；为非洲新记录种。此前曾有留尼汪的分布记录，但根据Grolle（1995）的研究，该记录实为波里羽苔（Plagiochila boryana）。 形态描述（另见Vanden Berghen, 1981，当时定为大纹羽苔；Heinrichs, 2002）： 植物体粗壮，宽约5mm；营养枝稀少，所有分枝均为间生枝，具根状茎状匍匐枝。 成熟茎叶松散覆瓦状排列，平展，近对生，呈卵状长圆形至卵状三角形，长约为宽的1.5-2倍，基部最宽；腹面基部具高叶耳，茎叶部明显膨大，叶尖圆形，叶缘无增厚边，沿叶尖和腹缘具(5-)10-18枚粗三角形齿，齿长(3-)4-8个细胞，基部宽3-6个细胞，有时破碎；背、腹基部短狭下延，对生叶的基部几乎合生。 叶细胞稍伸长，大型，叶中部宽35-40μm；三角体中等大小，呈凹边三角放射状，无油体带区域；角质层平滑；油体未观察到。 腹叶缺失。 雄株未见。 雌苞叶大于营养叶，且齿更粗。 蒴萼（幼态）无柄，蒴萼口具多数三角形齿。 未观察到营养繁殖。 讨论： 大穗羽苔（隶属于Hylacoetis组）的识别特征为：植物体粗壮（至少宽5mm），具间生分枝，近对生的叶片，基部茎叶具叶耳且明显膨大，具三角形齿，叶细胞大型（叶中部宽35-40μm），角质层平滑。 本种与波里羽苔（Plagiochila boryana）形似，二者均具大型叶细胞，但后者叶互生，齿呈线形，角质层具乳突。 采自马达加斯加的标本曾被Stephani描述为大纹羽苔（Plagiochila granditexta Steph.），该种在各形态特征上均与大穗羽苔一致。 Vanden Berghen（1981）错误地将大纹羽苔的叶片绘为互生状态。