Home › Volumes › Mosses and Lichens › Herbarium

Herbarium — Part 7

Leaves at the base of the spore-case (perichaetial leaves).-Small, oval.

Habit of flowering.-Male and female flowers on separate plants (dioicous), male branches rather thick, yellow-brown, red, or olive-green.

Veil (calypira).-As in genus.

Spore-case.-Large, almost spherical, dark brown.

Pedicel.-As in genus.

Lid (operculum).-Saucer-like.

Teeth (peristome).-None.

Spores.-Rust-colour, mature in July.

Distribution.-Universal.

Genus ANDREAEA, Ehrh.

The species of the Genus Andreaea are found in small, brown or black, fragile tufts on granite or slate rocks in high altitudes. They are among the first mosses to grow on rock and are efficient agents in preparing soil for higher forms of plant life. The plants are small with forked branches which start from just below the flower-bearing apex. The leaves are thick, open or spreading, ovate to lance-shaped and usually have their surface covered with projecting points.

The terminal oval spore-cases are immersed among the leaves before maturity, but later are protruded by the elongation of the cellular sheath (vaginule) surrounding the base of the spore-case. This is known as a false pedicel (pseudopodium). There is no lid, as the case opens by splitting perpendicularly into four or rarely six equal segments which cohere at the apex. There are, of course, no teeth when there is no lid. The small spores are at first coherent in fours, later, when the case splits into valves, they are disseminated by the wind, if the weather is dry; if it is damp, the valves draw together to protect the spores.

There are about one hundred species known at present, six or more of them occurring in North America. The specific characters are drawn mainly from the leaves.

By the early writers these mosses were classed with the leafy hepatics (Jungermania) on account of their manner of opening the spore-case by valves instead of by a lid. They agree in structure with the true mosses. Their proper place seems to lie between the peat-mosses and leafy-mosses. They agree with the peat-mosses because the spore-case is first enclosed in a saclike vail and then elongated on a false pedicel. They agree with the genus Grimmia in habitat, manner of growth and in structure of their leaves, differing chiefly in the opening of the spore-case.

The name was given by Fredrich Ehrhart, in honour of his friend J. G. R. Andreae, a Hanoverian naturalist.

The Stone-loving Andreaea (Andreaea petrophila), Ehrh.

Habit and habitat.-Found in small olive or dark brown tufts on wet rocks of high mountains.

Name.-From netpa, a rock, and, to love, referring to its choice of habitat.

Plants (gametophyte).-Stems slender, 1/3 to 1 inch long, leafless below.

Leaves.-Spreading or turned to one side, lance-shaped, rough on the back with projecting points; apex sometimes oblique, transparent; vein none, margin incurved, entire.

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

Veil (calyptra).-Thin, closely fitting the spore-case.

Spore-case.-Egg-shaped, immersed in the leaves at its base until maturity and then protruded by the elongation of the cellular sheath (vaginule) surrounding its base.

Pedicel (seta).-None.

Lid (operculum).-None.

Teeth (peristome).-None.

Spores.-Small, mature in June-August.

Distribution.-Widely distributed in cooler regions.

The Rock Andreaea rupestris), Turner.

Andreaea rupestris has lance-shaped leaves, smooth and with a vein extending beyond the apex.

This moss is common in the mountains of Georgia and North Carolina, descending to the plains northward.

The specific name from the Latin rupes, a rock, refers to its habitat.

Genus SPHAERANGIUM, Schimp.

The Species of the Genus Sphaerangium are minute bud-like plants with spore-case immersed, without stems, growing on the ground in clusters, but with no protonema at the base. The lower leaves are small, while the upper are large, somewhat twisted and overlapping as shingles. They are concave or keeled and covered with minute protuberances on the back or on both surfaces. The spore-cases are spherical and for this reason Wilhelm Philipp Schimper gave them their generic name Sphaerangium, from the Greek, a ball, and, a vessel. The cases with their tiny erect veils are borne on pedicels and are enclosed in the leaves at their base; when mature they split irregularly and transversely for the emission of the spores, which are small, somewhat globular, minutely granulous and brown.

There are fourteen species known in all, four of them in North America.

Sphaerangium muticum, Schimp. Individual plants are more or less separated.

Habit and habitat.-On bare clay or sandy soil.

Name.-The specific name muticum, blunt, refers to the apex of the spore-case.

Plants (gametophyte).-Like yellow-brown buds 1/8 of an inch high.

Leaves.-The lower and middle oval and long taper-pointed; apex recurved, with a short sharp point; vein passing beyond the apex; the upper two or three, twice as large as the lower; apex irregularly toothed.

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