Fig. 150—Usnea Florida. (Old Trees.) of leafy stem, called a frond or thallus, the branches of which are called podetia (see a in figs. 150, 151, and 152). The spores or sporules are produced in what are called shields (b in
Fig. 151.—Ramalina fastigiata. (Rocks and Trees.) figs. 149, 150, and 151), which are generally embedded in the thallus, and which, when they are cup-shaped (as in fig. 150), are called scyphæ, and when flat (as in fig. 151), apothecia. The sporules, which are very numerous, are inclosed in
Fig. 152.—Cornicularia heteromalla.—(Old Trees.) receptacles of various forms, which are embedded in the shields. Some of the commonest lichens are Usnea florida (fig. 150), and Ramalina fastigiata (fig. 151), both of which are found on old oaks, and are generally called grey moss; and Cornicularia heteromalla (fig. 152) is a brown mossy-looking lichen, often found on the bark. Other more interesting lichens are—the Iceland-moss (Cetraria islandica), the Reindeer-moss (Cenomyce, or Cladonia rangiferina), the Cup-moss (Cenomyce pyxidata), and the Orchil (Rocella tinctoria).
ORDER CCXIX.—FUNGI.
The Fungi are divided into several distinct sections; the most important of which may be called the Mushroom tribe. The largest genus in this division is Agaricus, and the plants belonging to it consist of a stipe, or stalk (c in fig. 149), surmounted by the pileus or cap (d). When the mushroom first appears, the stalk is covered by a thin membrane, called the veil (e), which unites the cap to the lower part; but as the mushroom grows, this veil is rent asunder, and it either entirely disappears, or only a small part of it remains round the stalk, which is called the annulus or ring. Under the cap are the gills or lamellæ, which are of a dark reddish brown; and attached to these are the thecæ, containing the sporules or seed. In the common Mushroom (Agaricus campestre), and all the eatable kinds, the gills are pink when the veil breaks, which it does very soon, and they become afterwards nearly black; but in all the poisonous kinds, the veil is longer before it breaks, and when it does so, the gills are pale, and frequently nearly white, without becoming darker; the smell is also quite different. The Mushroom tribe, which includes all the Fungi that carry their sporules in the part above the stem, is divided into two sections, viz., those with caps, like the Mushroom, and those which are slender and entire, but club-shaped in the upper part, like Clavaria helvola, a fungus often found in meadows, which resembles the stamen of an orange-lily.