Bot. Bull. Acad. Sin. (1997) 38: 263-266

Chiang Miehea new to China

Miehea (Family Leskeaceae), a genus new to moss flora of China

Tzen-Yuh Chiang

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

(Received May 17, 1997; Accepted July 18, 1997)

Abstract. Miehea indica (Dixon) Ochyra is reported as a new generic and species record of the moss flora of China. Although Miehea appeared on the annotated checklist of Chinese mosses of Redfearn et al. (1996), no voucher specimen was ever cited. The taxonomic position of Miehea remains uncertain. It was either put in the Hylocomiaceae based on the presence of foliose paraphyllia and a sympodial growth-form or in the Thuidiaceae on the basis of shared leaf-shape and leaf areolation. After examining the ontogeny of the undivided and foliose paraphyllia of M. indica, a closer relationship to Leskeaceae is thus proposed.

Keywords: China; Leskeaceae; Miehea; New record; Ontogenetic transformations; Undivided paraphyllia.


Miehea indica (Dixon) Ochyra was first recorded as a member of the moss flora of China in a recent annotated checklist (Redfearn et al.,1996) based on a personal communication with Dr. D. G. Long, a British bryologist. Nevertheless, no voucher specimens were ever cited. Lately a specimen collected from Yunnan Province of China and deposited at the Missouri Botanical Garden was examined when I made a monographic study on the Hylocomiaceae (Chiang, 1994). This finding has extended the geographic range of this genus beyond India.

Miehea was created by Ochyra (1989) based on M. himalayana, which was later synonymized into M. indica [Basionym: Hylocomium indicum Dixon] (Ochyra, 1991). This monotypic genus was characterized and distinguished from Hylocomium by having unbranched and foliose paraphyllia and the presence of longitudinal hyaline lamellae on the surface of the stems and branches (Ochyra, 1989). Nevertheless, the taxonomic position of Miehea still remains open.

Miehea Ochyra, Nova Hedwigia 49: 323. 1989.

Miehea indica (Dixon) Ochyra, J. Hattori Bot. Lab. 69: 124. 1991. (Figure 1)

Hylocomium indicum Dixon, Not. R. Bot. Gard. Edinburg 19(95): 299, f. 13. 1938.TYPE: India, near the sources of the Jumna, 12-14,000 ft., October 1868, coll. W. Bell, Herb. Edin. (110) (Holotype: E!)

Ptychodium indicum (Dixon) Rohrer, Lindbergia 12: 35. 1986.

Miehea himalayana Ochyra, Nova Hedwigia 49: 324. f. 1-3. 1989.TYPE: Nepal - Central Himalayas,

Keldang, Dupku Danda, elev. 4,660 m; E-facing scree slope exposed to monsoon rain, 27 July 1986, Sabine & George Miehe 6845 (Holotype: KRAM-B!).

Plants medium-sized, in loose mats. Stems julaceous and sympodially branched. Central strands not differentiated. Paraphyllia abundant, scattered on stems and branches, foliose and undivided, usually long decurrent. Leaves of main stems, secondary stems and branches differentiated. Stem leaves concave, oblong-ovate with abruptly narrowed apiculate apex, branch leaves ovate-elliptic with tapering acute apex; margins entire, strongly recurved; costa single, occasionally forked, extending to 4/5 the leaf length; leaf base decurrent. Leaf cells linear, ca. 30_65 m long, smooth, with moderately thickened walls; angular cells less differentiated, rectangular; basal cells strongly pitted. Sporophytes not seen.

Specimen examined. China, Yunnan, Long 18998 (MO).

Distribution. India, Nepal, and China.

Notes. An unusual character, with longitudinal lamellae on stems and branches, was emphasized in Ochyra's (1989) taxonomic discussion of Miehea. Longitudinal lamellae were first used to describe a non-chlorophyllous structure composed of one to four inflated hyaline cells, on stems or branches of Pleuroziopsis ruthenica (Weinm.) Kindb. (Ireland, 1968). Longitudinal lamellae, from which branched rhizoids arise, were therefore suggested to be different from the true paraphyllia (Ireland, 1968; also cf. Lawton, 1971; Noguchi, 1994). Based on this character and others, Buck and Vitt (1986) recognized the Pleuroziopsidaceae as a family phylogenetically distant from the Climaciaceae. In contrast, Ochyra (1989) suggested a different phylogeny, in which Pleuroziopsis was closer to Climacium than any other pleurocarpous mosses, due to the recognition of the stem lamellae of Pleuroziopsis as the true paraphyllia.

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Botanical Bulletin of Academia Sinica, Vol. 38, 1997

Figure 1. Miehea indica (Dixon) Ochyra. A_B, Stem leaves (33); C_D, Branch leaves (33); E, Apical cells of stem leaf; F, Median laminal cells (330); G, Alar and basal cells of branch leaf (330); H, Alar and basal cells of stem leaf (330); I_M, Paraphyllia (33); N, Cross section of stem (330). Drawn from Long 18998.

Chiang Miehea new to China

This species is found as a new addition at both specific and generic levels to moss flora of China.

Acknowledgments. I am grateful to the curators of herbaria of the Royal Botanical Garden, Edinburg (E), Missouri Botanical Garden (MO), and Botanical Institute of the Polish Academy of Sciences (KRAM) for the loans of the type specimens. I thank Profs. S. H. Lin and H. Deguchi and an anonymous reviewer for their instructive comments.

Literature Cited

Buck, W.R. and D.H. Vitt. 1986. Suggestions for a new familial classification of pleurocarpous mosses. Taxon 35: 21_60.

Chiang, T.Y. 1994. Phylogenetics and evolution of the Hylocomiaceae (Mosses, Order Hypnales). Ph.D. Dissertation, Division of Biology and Biomedical Sciences, Washington University, St. Louis, Missouri, USA.

Chiang, T.Y. 1995. Phylogeny and morphological evolution of Macrothamnium M. Fleisch. and related taxa (Bryopsida: Hypnaceae). Bot. Bull. Acad. Sin. 36: 143_154.

Crum, H. 1976. Mosses of the Great Lakes Forest. Revised edition, Ann. Arbor. Michigan, 404 pp.

De Queiroz, K. 1985. The ontogenetic method for determining character polarity and its relevance to phylogenetic systematics. Syst. Zool. 34: 280_299.

Dixon, H.N. 1938. Notes on the moss collections of the Royal Botanical Garden, Edinburgh. Not. Roy. Bot. Gard. Edin. 19: 279_302.

Ireland, R.R. 1968. Pleuroziopsidaceae, a new family of mosses. J. Hattori Bot. Lab. 31: 59_64.

Lawton, E. 1971. Moss Flora of the Pacific Northwest. Hattori Botanical Laboratory, Nichinan.

Noguchi, A. 1994. Illustrated Moss Flora of Japan, Part 5. Supplemented by Zen. Iwatsuki and T. Yamaguchi, Hattori Botanical Laboratory, Nichinan.

Ochyra, R. 1989. Miehea himalayana, a new species and genus of Hylocomiaceae (Musci) from the Himalayas. Nova Hedw. 49: 323_332.

Ochyra, R. 1991. On the taxonomic position of Hylocomium indicum Dixon (Musci, Hylocomiaceae). J. Hattori Bot. Lab. 69: 121_127.

Redfearn, Jr.P.L., B.C. Tan, and S. He. 1996. A newly updated and annotated checklist of Chinese mosses. J. Hattori Bot. Lab. 79: 163_357.

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

Rohrer, J.R. 1986. Taxonomic notes on Rigodiadelphus, Ptychodium, and Okamuraea: three genera misplaced by Fleischer in the Rhytidiaceae. Lindbergia 12: 33_40.

Takaki, N. 1955. Researches on the Brachytheciaceae of Japan and its adjacent areas (1). J. Hattori Bot. Lab. 14: 1_28.

Wagner, G.P. 1989. The origin of morphological characters and the biological basis of homology. Evolution 43: 1157_1171.

Although Ochyra (1989) concluded that Miehea was the only genus having differentiated longitudinal lamellae, his definition of longitudinal lamellae in Ochyra (1989) appeared quite puzzling. First he described (p.329) and illustrated (Fig. 2:2-3) the decurrencies of paraphyllia which gradually merged into the longitudinal lamellae of the stems and branches. That is, lamellae were parts of the paraphyllia. But on the next page, he stated, "Originally I assumed these (lamellae) were long decurrencies of leaves or paraphyllia. However, transverse sections of the stems and branches revealed many distinctive hyaline lamellae which are usually 3_4, and only occasionally 1 or 5, cells high. However, there are many lamellae that are totally independent of the paraphyllia." When the structures in question were examined with care, "lamellae" with three or four hyaline cells, which were abundantly distributed on stems, were easily detected under microscope even without dissection. Nevertheless, I would rather interpret them as early-stage paraphyllia, not "longitudinal lamellae" because of their identical areolation and unbranched shape. To recognize the same feature of different ontogenetic stages as different characters usually causes inevitable mistakes in phylogenetic reconstruction.

The taxonomic position of Miehea remains controversial. Ochyra (1991) revised this genus and retained it in the Hylocomiaceae emphasizing the sympodial growth-form and the undivided paraphyllia. In addition to Ochyra's treatment Rohrer (1986) transferred Hylocomium indicum into Ptychodium, a genus of Thudiaceae (Crum, 1976; Rohrer, 1985), on the basis of the similarity of leaf shape and areolation as well as the presence of paraphyllia. Obviously the presence of paraphyllia was emphasized in both hypotheses. And even the undivided, foliose morphology of paraphyllia has been claimed to be a type of hylocomiaceous moss (Ochyra, 1991). However the paraphyllia of both Hylocomiaceae (Chiang, 1994) and Ptychodium (Ochyra, 1991) are all branching and do not resemble those of Miehea.

In phylogeny reconstruction, ontogenetic data of individualized and complex phenotypic characters (Wagner, 1989) usually provide more phylogenetic information than any instantaneous traits (De Quieroz, 1985). In mosses the ontogenetic sequence of paraphyllia has been proved to be more informative than the adult morphology or the mere use of absence or presence criterion (Chiang, 1995; also cf. Buck and Vitt, 1986). The ontogenetic transformations of the undivided paraphyllia not only falsify the above hypotheses but also imply a closer relationship of Miehea to the Leskeaceae. A paraphyllia bearing genus Pseudopleuropus Takaki, which was catalogued in the Brachytheciaceae (Takaki, 1955), with sympodial growth-form as well, may be the taxon most closely related to Miehea phylogenetically. More evidence for testing the above hypothesis will be discussed in detail elsewhere.

Botanical Bulletin of Academia Sinica, Vol. 38, 1997




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