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Thread-moss

Genus LEPTOBRYUM, Schimp.

The species of the Genus Leptobryum live but one year, the plants are unbranched above, new growths coming only from the base. The generic name from the Greek ??, slender, and ??, a moss, refers to the slender character of the plants.

The leaves are narrow, glossy, and turn in different directions. The apex is like an awl and the cells are narrowly rhomboidal above, looser toward the base and rectangular-six-sided.

The spore-cases are inclined or pendent, long-necked and thin-coated with convex lids tipped with a small point. The teeth are double, the intermediate hair-like segments having cross-bars projecting beyond the edge.

There are but few species known at present, one of these is found in North America.

The Pear-shaped Thread-moss, Leptobryum pyriforme, Schimp.--See cuts on page 218.

Habit and habitat.--In dense silky green patches on shady rocks and walls, and sandy or turfy soil, also on burnt and decaying trees. Common.

Name.--The specific name pyriforme is from the Latin pyrum, a pear, and forma, form, referring to the spore-case.

Plant (gametophyte).--Slender, simple, stem short. One-half to one inch high.

Leaves.--The lower distant, narrowly lance-shaped, the upper tufted and longer; apex awl-like, flexuose, serrate; cells above, narrow and long, below, broader. Vein dilated at the base, extending below the apex.

Habit of flowering.--Male and female flowers together, (synoicous).

Spore-case.--Pear-shaped or oval, yellow-brown, glossy, symmetrical, neck long.

Pedicel.--Red, slender, 1 to 2 inches long.

Lid (operculum).--Convex, with a tiny nipple.

Teeth (peristome).--Pale yellow, lance-shaped, segments of the inner membrane keeled and perforated; the thread-like segments bearing little knots on the edges.

Annulus.--Broad, rolling back as the lid falls.

Spores.--Mature in May and June.

Distribution.--Universal.

Genus WEBERA, Hedw.

The members of this genus are similar to those of the genus Bryum, the essential characters which separate the two are that Webera has rhomboidal-hexagonal, narrow, and more or less linear leaf-cells with a slender vein, while Bryum has rhomboidal-hexagonal, smooth, usually broad and loose cells, with a solid, round vein generally passing beyond the apex of the leaf.

The name was given by J. G. Hedwig, a German botanist, in honour of G. H. Weber.

Webera nutans, Hedw.--See Plate XVII. Also see cuts on page 217.

Habit and habitat.--This pretty moss is common, growing in soft cushions on moist ground, in peat bogs and swamps and in fissures of rocks.

Name.--The specific name nutans, the Latin for "nodding," describes the spore-case.

Plant (gametophyte).--Yellow-green; stem slender and flexible, 1/2 to 2 inches high.

Leaves.--The lower ovate-lanceolate, margin entire; the upper linear-lanceolate, serrate at the apex; vein thick, reddish, glossy, vanishing below the apex.

Habit of flowering.--Male and female flowers on the same plant (monoicous).

Spore-case--Oblong-ovate with a broad opening, yellow-brown, short-necked, inclined or pendent.

Pedicel.--Glossy red, often two inches high.

Lid (operculum).--Highly convex, with a tiny nipple.

Teeth (peristome).--Dark orange, pale and thread-like at the apex, the segments of the inner membrane pale-yellow, split, slender segments (cilia) 2 to 3 strongly jointed, as long as the teeth.

Annulus.--Large, rolling back as the lid falls.

Spores.--Mature in summer.

Distribution--Almost universal.

Webera albicans, Schimp.--See Plate XVII.

Habit and habitat.--This pretty moss grows in soft tufts of a light-green colour in wet sand on the borders of streams, and in swampy land along wheel ruts.

Name.--The specific name albicans, whitish, has reference to its peculiar pale-green colour.

Plant (gametophyte).--Simple, erect or inclined; 1 to 4 inches long; stem reddish or dark-purple.

Leaves.--The lower ovate, oblong and taper-pointed, the upper oblong-lanceolate, soft, yellowish or pale-green; vein vanishing below the apex; margin serrate near apex; leaves around the male flowers broad and concave at the base, open and lanceolate above.

Habit of flowering.--Male and female flowers on separate plants, male flowers in a disk-like head.

Spore-case.--Inclined or pendent, short-pear-shaped, inflated at the neck (collum); green with a bloom, becoming brown; somewhat round and wide-mouthed when empty.

Pedicel.--Long, generally reddish and bent at the base.

Lid (operculum).--Conical with a nipple (mammillate).

Teeth (peristome).--Large, orange-coloured.

Annulus.--None.

Spores.--Mature in spring and early summer.

Distribution.--Almost universal.

Genus BRYUM, Dill.

The plants of the Genus Bryum live on from year to year on the ground or on rocks, seldom on trees. The stems are covered with small red-brown filaments.

The generic name is an ancient word for moss used both by Gaius Plinius, "The Elder," a Roman naturalist, who perished in the eruption that destroyed Pompeii, and by Pedanius Dioscorides, a Greek physician, who was the founder of botany and flourished in the first and second century. The name Bryum was restricted to the present genus by Johann Dillenius, a German, who was the first professor of botany at Oxford.

The leaves are smooth with a solid round vein generally extending beyond the apex; the cells are smooth, six-sided and more or less elongated.