The Lichens are divided into two Orders, according to whether the apothecia are open before the spores are ripe, as in the species noticed above, or whether the apothecia only open to discharge the ripe spores. The first Order forms the Gymnocar´pi (γυμνὀς, naked, καρπὀς, fruit); the second forms the Angiocar´pi (ἁγγεῖον, vessel, capsule).

Preservation.—The Lichens are readily preserved, on account of their dry nature; they need simply be kept in a dry place, and glued to pieces of card. If room is an object, they may be dried under pressure, as in the case of the flowering plants. When re-moistened, the minute structures may be easily made out by sections. The smaller ones may be mounted dry, in cells made of the wax cement (p. 16). The minute structures keep well in chloride of calcium or glycerine.

CHAPTER IX.
FUNGI.

THE Fungi form the lowest class of plants: as examples of them, may be mentioned mushrooms, toadstools, puff-balls, the mould of paste, the blue mould of cheese, &c. The more minute Fungi are very common, forming beautiful microscopic objects, although they are rarely studied by the microscopic observer.

Fungi live usually upon rotting or decaying vegetable substances, as rotten wood, the dead leaves and stems of plants, &c.; but sometimes they are found upon living plants, and some of them exist upon decaying animal matters, and even in living animals.

Fungi exhibit no separation of root, stem, or leaves, as exists in the higher plants; nor do they contain chlorophyll, the presence of which is so generally associated with the idea of a plant. But they consist of aggregations of mostly elongate cells, forming branched and interlacing colourless fibres, buried like roots in the substance (matrix) upon which they grow, and from which they derive their nourishment; this portion of the Fungus is called the mycélium (μὑκης, a fungus). The portion of the Fungus projecting beyond the surface of the matrix is the fructification; and this is the part usually called the fungus, the mycelium being overlooked by a casual observer. So that here we have a character distinguishing the Fungi from the Lichens, which derive their nourishment from the air, and not from the matrix. The absence of the green cells, or gonidia, forms another character by which the nearly allied members of this class of plants can be distinguished.

PLATE VII. [[PLATE 96.]]
Fungi.
Fig.
1.Agaricus micaceus: a, gills.
2.Agaricus campestris: a, spores; b, basidia.
3.Physarum album, on a piece of stick.
4.Physarum album, spores.
5.Uredo segetum, spores.
6.Uredo caries, spores.
7.Uredo candida, on leaf of Shepherd’s Purse (Capsella): s, spores.
8.Æcidium grossulariæ, sorus.
9.Æcidium grossulariæ: p, spore-capsules (peridia); s, anther-capsules (spermogonia).
10.Nemaspora crocea: a, spores.
11.Torula casei.
12.Torula herbarum, on a piece of stick.
13.Torula herbarum, spores.
14.Phragmidium bulbosum, on bramble-leaf.
15.Phragmidium bulbosum, stylo-spores and paraphyses.
16.Puccinia graminis, on a piece of straw.
17.Puccinia graminis, spores.
18.Sporocybe alternata, filament and spores.
19.Botrytis parasitica, on Shepherd’s Purse.
20.Botrytis parasitica, spores and filaments.
21.Rhinotrichum, species of.
22.Rhinotrichum, heads of spores.
23.Rhinotrichum, spores detached.
24.Rhinotrichum, spores.
25.Penicillium glaucum.
26.Penicillium glaucum, head of spores.
27.Coremium leucopus.
28.Tubercularia vulgaris.
29.Tubercularia vulgaris, divided receptacle.
30.Tubercularia vulgaris, filaments.
31.Tubercularia vulgaris, spores.
32.Sphæria fragiformis.
33.Trichothecium roseum, on a piece of stick.
34.Trichothecium roseum.
35.Trichothecium roseum, filaments and spores.