Chiang and Hsu — Synonym of Hylocomiastrum himalayanum
Bot. Bull. Acad. Sin. (1999) 40: 243-245
Re-examination of Bryonoguchia brevifolia, a new synonym of Hylocomiastrum himalayanum
Tzen-Yuh Chiang1,3 and Tsai-Wen Hsu2
1Department of Biology, Cheng-Kung University, Tainan 700, Taiwan
2Taiwan Endemic Species Research Institute, Chi-Chi, Nantou Co., Taiwan
(Received August 4, 1998; Accepted October 26, 1998)
Abstract. Bryonoguchia brevifolia S. Y. Zeng reported from China is examined and is considered conspecific with Hylocomiastrum himalayanum (Mitt.) Broth., a species widespread in the Himalayas, China, Taiwan, and Japan. Hylocomiastrum is distinguished from Bryonoguchia by its sympodial growth-form and reindeer-horn paraphyllia. In contrast, Bryonoguchia is characterized by having filiform paraphyllia and uni-papillose leaf cells. Byonoguchia is now a monotypic genus of the Thuidiaceae.
Keywords: Bryonoguchia brevifolia; Growth-form; Hylocomiastrum himalayanum; Paraphyllia; Synonym.
Bryonoguchia is a genus of two species: B. molkenboeri (Lac.) Iwatsuki & Inoue and B. brevifolia Zeng. The regularly bipinnate habit, differentiated stem and branch leaves, and branching filiform paraphyllia of B. molkenboeri resemble those of the Thuidium species. A diagnostic character, i.e. paraphyllia differentiated on the leaf base and lower costa, distinguishes Bryonoguchia from Thuidium (Noguchi, 1994). However, Zeng (1991), whose Figure 1 described Bryonoguchia brevifolia, showed only differentiated stem and branch leaves. Since Zeng's paper (1991) failed to take into account pertinent literature included in Chiang and Hsu (1997), it is reasonable to doubt whether the author looked up important references or checked for possibly related taxa before the new species was published. The presence of hornlike paraphyllia (Noguchi, 1972) and smooth leaf cells in B. brevifolia indicate it is more related to the Hylocomiaceae than the Thuidiaceae. Indeed on the basis of the sympodial growth-form, reindeer-horn paraphyllia, and smooth leaf cells, we synonymize Bryonoguchia brevifolia with Hylocomiastrum himalayanum (Mitt.) Broth.
Hylocomiastrum himalayanum (Mitt.) Broth. in Engler & Prantl, Nat. Pfl. ed. 2, 11: 486. 1925. Figure 1
Basionym: Stereodon himalayanus Mitt., J. Linn. Soc. Bot. Suppl. 1: 113. 1859.
Bryonoguchia brevifolia S. Y. Zeng, Acta Botanica Yunnanica 13: 377. f. 1.1991. syn. nov. Holotype: Yunnan: Weihsi County, Da-Cheng Zhang 743a (KUN).
Illustrations of Hylocomiastrum himalayanum: Rohrer (1985) Fig. 3. d-f; Noguchi (1994) Fig. 529; Koponen (1979) f. 10.
Plants robust, growth-form sympodial, bipinnate; paraphyllia abundant on stems and branches, reindeer-horn type (cf. Noguchi, 1972); stem and branch leaves differentiated; leaf margins dentate; costa single, 4/5 leaf length; median cells linear, smooth or prorate; basal cells brown, quadrate; alar cells not different from the basal cells.
Distribution. Himalayas, China, Taiwan, Japan.
Additional specimens examined. Hylocomiastrum himalayanum (Mitt.) Broth.: Japan, Honshu, Inoue 936, 487 (MO), Schofield 51994 (MO). Bryonoguchia molkenboeri (Lac.) Iwatsuki & Inoue: Japan, Hokkaido, Higuchi s.n. (HAST; exsiccati: bryophytes of Asia, Fasc. 2: 28, distributed by Hiroshima University).
A derived character, "reindeer-horn" paraphyllia (Noguchi, 1972), distinguishes Hylocomiastrum from other genera of the Hylocomiaceae. The close relationship between H. himalayanum and H. umbratum has been suggested by their many shared similarities (Koponen, 1979; Rohrer, 1985). Hylocomiastrum himalayanum differs from H. umbratum in having leaves with a single costa instead of two. From the other single costate species, H. pyrenaicum (Hedw.) Fleisch., H. himalayanum is regularly bi-pinnate rather than irregularly branched (Rohrer, 1985). Accordingly, H. himalayanum illustrated on Fig. 184: 11-16 of Li et al. (1985) seems more likely to be H. umbratum. This makes the distribution of H. himalayanum in Tibet uncertain since no specimens have been specifically cited in earlier literature (cf. Redfearn et al., 1996).
3Corresponding author. Tel: +886-6-2757575 ext. 65525; Fax: +886-6-2742583; E-mail: tychiang@ccvax.sinica.edu.tw
