Leucobryum (PROSEA)

Plant Resources of South-East Asia Introduction

List of species

Leucobryum Hampe

Protologue: Linnaea 13: 42 (1839).

Family: Leucobryaceae

Chromosome number: x= 11

Major species and synonyms

• Leucobryum aduncum Dozy & Molk., Pl. Jungh. 3: 319 (1854).

• Leucobryum javense (Schwaegr.) Mitt., Journ. Linn. Soc. Bot. Suppl. 1: 25 (1859).

• Leucobryum sanctum (Brid.) Hampe, Linnaea 13: 42 (1839).

Vernacular names

• Cushion moss, white moss (En). (Tagalog)
• Indonesia: putih lumut
• Malaysia: putih lumut
• Philippines: puting lumot

Origin and geographic distribution

Leucobryum is a mainly tropical genus of about 150 species. It is pantropical, but some species occur in temperate regions, e.g. L. glaucum (Hedw.) Ångstr., which occurs in temperate Europe, Asia and America, and in Hawaii and the Andes. All Leucobryum species treated here are widespread and common in South-East Asia, and known also from India, Indo-China, Thailand, China and Japan. L. sanctum occurs, in addition, on some Pacific islands.

Uses

Because of the capacity to store large amounts of water in the leaves, species of Leucobryum, together with Leucophanes octoblepharioides Brid. and other members of the family, are used by gardeners or plant growers as a local substitute for peat moss ( Sphagnum) in potting new plants. According to plant growers in Manila, cushion moss induces good root sprouts in orchid cuttings. Less frequently it is used as filling material for transporting fragile commodities. In parts of Peninsular Malaysia it is used, together with other mosses, such as Campylopus , to stuff cushions and mattresses. In Japan, cushion moss is preferred in bonsai landscape design, and in Europe it is commonly used in floral decoration.

Production and international trade

Leucobryum is sold in local markets and department stores in small packages in many South-East Asian countries. In the Philippines, a kilo of dry, mixed Leucobryum material costs about US$ 1 in 1986. It is collected from the wild in nearby mountains. No international trade exists and it is not cultivated commercially.

Properties

Laboratory tests showed that water and alcohol extracts of Leucobryum have strong anti-microbial activity against bacteria and fungi.

Description

Terrestrial mosses, whitish in colour when dry, bluish-green or pale green when wet, forming rounded, compact or more loose cushions, sometimes of considerable size; plants up to 15 cm long, occasionally more. Leaves dense, mostly turned to one side, about 3-10(-15) mm long and 1-1.5 mm wide, thick, composed largely of midrib, with a few rows of narrow, hyaline cells towards the base representing the lamina, several-stratose; midrib in section with 2-several layers of hyaline cells with large circular pores on the inner surface, and with a small central layer of chlorophyllose cells. Sporophytes infrequently present. Capsule erect or inclined, straight or curved, on an often reddish seta, without stomata; peristome teeth 16, bifid, transversely articulated with fine vertical striae between the articulations; operculum with long beak.

Growth and development

Leucobryum species are usually long lived, slow growing mosses. They are usually dioecious, with male plants in separate clumps or growing in female clumps and then small.

Other botanical information

Leucobryum is sometimes classified in the family Dicranaceae , a somewhat heterogeneous family that is not clearly defined. Leucobryum is distinguished by its leaves consisting mainly of midrib composed of 2 or more layers of large hyaline cells.

Ecology

Species of Leucobryum prefer acidic, wet and humic substrates. Of the three species, L. aduncum tolerates more dryness than the other two, which are shade species of the forest floor, trail margins, tree trunks or decaying logs.

Management

Leucobryum is easily transplanted from the wild into gardens by transferring whole clumps together with the substrate and placing them under similar conditions as in the wild. Attempts to cultivate and enlarge the clumps by mechanical means have achieved little success.

Genetic resources

When the demand becomes too high, populations of Leucobryum may easily become endangered. This is already the case locally in Europe, where commercial gathering depleted natural populations of L. glaucum in some regions.

Prospects

Like Sphagnum, Leucobryum will remain of limited importance on the market in South-East Asia. Supply from natural populations is limited and large-scale commercial cultivation impossible.

Literature

• Ablao, F.C.C., 1986. A survey of different species of Philippine bryophytes sold commercially around Greater Manila Area. B. Sc. (Botany) thesis. University of the Philippines at Los Baños, Laguna.
• Burkill, I.H., 1966. A dictionary of the economic products of the Malay Peninsula. Revised reprint. Vol. 1. Ministry of Agriculture and Co-operatives, Kuala Lumpur, Malaysia. p. 426.
• Johnson, A., 1980. Mosses of Singapore and Malaysia. Singapore University Press, Singapore. 126 pp.
• Raymundo, A.K., Tan, B.C. & Asuncion, A.C., 1991. Anti-microbial activities of some Philippine cryptogams. Philippine Journal of Science 118: 59-75.
• Yamaguchi, T., 1993. A revision of the genus Leucobryum (Musci) in Asia. Journal of Hattori Botanical Laboratory 73: 1-123.

Authors

Benito C. Tan