Bot. Bull. Acad. Sin. (1998) 39: 205_208

Chiang and Hu — Synonymization of L. morrisonensis fo. sichuanensis

Lescuraea morrisonensis (Takaki) Nog. fo. sichuanensis Wang, Hu & Redfearn, a synonym of Actinothuidium hookeri (Mitt.) Broth.

Tzen-Yuh Chiang¹ and Wei-Hsin Hu

Department of Biology, Cheng-Kung University, Tainan, Taiwan 700, Republic of China

(Received October 29, 1997; Accepted January 2, 1998)

Abstract. Lescuraea morrisonensis (Takaki) Nog. fo. sichuanensis Wang, Hu & Redfearn reported from mainland China is synonymized to Actinothuidium hookeri (Mitt.) Broth. Filiform branched paraphyllia and triangular stem-leaves which characterize A. hookeri are distinguishable from unbranched foliose paraphyllia and ovate-lanceolate stem-leaves of Lescuraea morrisonensis.

Keywords: Actinothuidium hookeri; China; Lescuraea morrisonensis fo. sichuanensis; Synonym.

Wang et al. (1993) published a new taxon, Lescuraea morrisonensis fo. sichuanensis, from mainland China. Their account, however, provided no detailed description or illustration of morphological features except for the filiform paraphyllia. The absence of information on leaf shape and areolation has caused difficulty in assessing this new forma, although the authors did emphasize its close affinity to Lescuraea morrisonensis (Takaki) Nog. On the other hand, the type specimen of Pseudopleuropus morrisonensis Takaki (= L. morrisonensis), a rarely known taxon, was not even examined when they added a new form to this species. A recent revision on Pseudopleuropus (Chiang, 1998) provided us an opportunity to re-examine the type materials. As a matter of fact, the illustration drawn in Wang et al. (1993) revealed the taxon may be more allied to the Hylocomiaceae or Thuidiaceae than the Leskeaceae. After examining the type materials, we synonymized L. morrisonensis fo. sichuanensis to Actinothuidium hookeri (Mitt.) Broth. based on the filiform branched paraphyllia and triangular stem-leaves.

Actinothuidium hookeri (Mitt.) Broth. in Engler & Prantl, Nat. Pflanzenfam. 1(3): 1020 (1908).

(Figure 1)

Lescuraea morrisonensis (Takaki) Nog. fo. sichuanensis Wang, Hu & Redfearn, Bryologist 96: 640. f. 1. 1993. syn. nov.—TYPE: CHINA. Sichuan Province. Li Co.: 4,270_4,300 m alt., Redfearn 34969 (holotype: HSNU!; isotypes: FH!, MO!)

Plants robust, 5_8 cm long, regularly pinnately branched, monopodial; branches 1.5_2.2 cm long, attenuate; central strand absent; paraphyllia numerous, filiform,

branched. Primary stem-leaves broadly ovate to triangular-ovate, with a curved lanceolate acumen, deeply plicate, costa 4/5 leaf-length, margins serrulate; secondary stem-leaves ovate-lanceolate, with a long, tapering acuminate apex; branch-leaves ovate, with a short apex; margins serrulate to denticulate. Median laminal cells rhomboidal, thin-walled, with a single papilla at upper end; alar cells differentiated, rectangular; basal cells pitted. Sporophytes not seen.

Distribution. Taiwan, China, Nepal, Himalayas.

Illustrations. Watanabe (1972): Pl. 30; Anonymous (1977): f. 185; Li (1985) f. 146.

Other specimens examined. BHUTAN. Bartholomeu 149 (MO); NEPAL. Kanai 476 (MO); CHINA. Sichuan, Maire s. n., Redfearn & Si 1369, Redfearn 34948a (MO).

Additional specimens examined. Pseudopleuropus morrisonensis Takaki—TYPE: TAIWAN. Mt. Morrison, Takaki 16285 (holotype: NICH!).

Notes. Actinothuidium hookeri, a species of the Thuidiaceae, is characterized by the filiform, branched paraphyllia, absence of central strands in stems, and differentiated primary and secondary stem-leaves and branch-leaves as well. In contrast, Lescuraea morrisonensis of the Leskeaceae is diagnosable by its sympodial growth-form, phyllodioicous sexuality, unbranched, foliose paraphyllia, and differentiated central strand in stems. The monopodial growth-form, regularly branching pattern, stems without differentiated central strands, well differentiated primary and secondary stem-leaves, and multi-branched, filiform paraphyllia observed from the type materials obviously support the conspecificity of L. morrisonensis fo. sichuanensis to Actinothuidium hookeri. As noted by Rohrer (1985) and Watanabe (1972) no sporophytic features of A. hookeri have been observed so far except for

¹Corresponding author. Tel: 011-886-6-2757575 ext. 65525; Fax: 011-886-6-2742583; E-mail: tychiang@mail.ncku.edu.tw

Botanical Bulletin of Academia Sinica, Vol. 39, 1998

Figure 1. Actinothuidium hookeri (Mitt.) Broth. A, primary stem leaf; B, secondary stem leaf; C_E, branch leaves; F, cross section of stem; G, apical cells of branch leaf; H, marginal cells of branch leaf; I, median cells of branch leaf; J, alar cells of branch leaf; K, basal cells of branch leaf; L_T, various stages of paraphyllia. Scale 1: 0.74 mm (A_E); 2: 0.053 mm (F_T) (Drawn from Redfearn 34969, holotype).

Chiang and Hu — Synonymization of L. morrisonensis fo. sichuanensis

the illustration of Brotherus (1925). Gametophytic features such as leaf differentiation and morphology of paraphyllia indicate its taxonomic position in the Thuidiaceae.

It is worth noting that the morphology of paraphyllia of Lescuraea morrisonensis has been described and illustrated differently by bryologists. In the original description paraphyllia were illustrated as forked and branched (see Fig. 5:8 in Takaki, 1955). Three paraphyllia, with two unbranched and one somewhat forked at apex, were also illustrated (Figure 1:c, Noguchi, 1985). Nevertheless, no such branched paraphyllia have ever been observed in our own examination of type material and other collections from Taiwan (T. Y. Chiang 5083). The unbranched paraphyllia and other morphological features indicate a close relationship between L. morrisonensis and Miehea species, which is discussed otherwhere in detail (Chiang, 1997, 1998).

In this study, we synonymized L. morrisonensis fo. sichuanensis to Actinothuidium hookeri and excluded it from the Leskeaceae.

Acknowledgments. We thank Prof. Ching-I Peng for getting the loan of type materials via Academia Sinica, Taipei. We are indebted to the curators of HSNU, Missouri Botanical Garden and Farlow Herbarium for the loan of types of Lescuraea morrisonensis fo. sichuanensis and to Prof. Zen Iwatsuki for the loan of Pseudopleuropus morrisonensis from NICH. We also

thank Prof. S. H. Lin and another anonymous reviewer for their valuable comments.

Literature Cited

Anonymous, 1977. Flora Muscorum Chinae Boreali-Orientalis. Science Press, Beijing.

Brotherus, V.F. 1925. Thuidiaceae. In Engler & Prantl, Nat. Pflanzenfam. edn 2, 11: 309_331.

Chiang, T.Y. 1997. Miehea (Family Leskeaceae), a genus new to moss flora of China. Bot. Bull. Acad. Sin. 38: 263_266.

Chiang, T.Y. 1998. A reassessment of taxonomic position of Miehea Ochyra. Bot. Bull. Acad. Sin. 39: 131_136.

Li, X.J. (ed.). 1985. Bryoflora of Xizang. Science Press, Beijing.

Noguchi, A. 1985. On Pseudopleuropus morrisonensis Takaki (Musci). Yushania 2: 23.

Rohrer, J.R. 1985. A phenetic and phylogenetic analysis of the Hylocomiaceae and Rhytidiaceae. J. Hattori Bot. Lab. 59: 185_240.

Takaki, N. 1955. Researches on the Brachytheciaceae of Japan and its adjacent areas (1). J. Hattori Bot. Lab. 14: 1_38.

Wang, Y.F., R.L. Hu, and P.L. Redfearn, Jr. 1993. Lescuraea morrisonensis fo. sichuanensis (Musci: Leskeaceae), a new form from Sichuan, China. Bryologist 96: 640.

Watanabe, R. 1972. A revision of the family Thuidiaceae in Japan and adjacent areas. J. Hattori Bot. Lab. 36: 171_320.