Gasteromyce´tes (γαστἠρ, belly, hollow, μὑκης, fungus).—This order of Fungi, which contains the Puff-balls and many others not readily procured, must be very briefly noticed. The spores are contained in a capsule or perid´ium (πηρἱδιον, a little bag) which is often of large size, and are situated upon a hymenium forming folds, partitions (septa), or a lattice-work.
A small species, Physárum album ([Pl. VII.] fig. 3), is often found growing upon rotten stems of plants and decaying sticks. The capsules are minute, grey, brittle, and black within, from the presence of the spores (fig. 4), which are lens-shaped, and arise from the ends of short filaments.
Coniomyce´tes (κὁνις, dust, μὑκης, fungus).—This Order contains some beautiful microscopic Fungi, several of which are very common. Many of them grow upon living plants, while others are found upon decaying stems, sticks, &c. The mycelium consists of inconspicuous, fine filaments, which run beneath the epidermis and bark of leaves and stems, or exist in the intercellular passages, the fruit bursting through the surface. The spores are short-stalked, forming sty´lospores (στῦλος, stalk, σπὁρος, seed) or conid´ia (κονἱδιον, little dust). But there is great confusion in the descriptions of the spores of the same Fungus by different botanical authors, some describing the fruit (in [Pl. VII.] fig. 15, for instance) as composed of rows of spores, while others regard it as forming a single septate (septum, a partition) or partitioned spore.
Tor´ula herbárum ([Pl. VII.] fig. 12) is very common on the decaying stems of plants, especially those belonging to the Parsley order (Umbelliferæ), forming greenish-black streaks or patches. The spores (fig. 13) are grouped into chains or beaded (moniliform) rows, with very short stalks, and these are crowded to form the black patches visible to the naked eye. Under the microscope the spores appear of a brown colour.
Torula cásei ([Pl. VII.] fig. 11) forms reddish or white patches upon decaying cheese. It consists of branched, interwoven, tufted filaments (flocci), with comparatively large spherical spores arranged in rows at their ends.
Nemas´pora crócea ([Pl. VII.] fig. 10) is a very curious member of this Order, and is found upon decaying beech-sticks. It appears as an orange-coloured tendril-like gelatinous mass of spores, bursting through a little pore on the surface of the bark. The spores (fig. 10 a) are very minute, slender, and curved, and under a high power appear jointed.
Æcid´ium grossuláriæ ([Pl. VII.] fig. 8) is found very commonly on the leaves of the gooseberry-bush. It forms to the naked eye oval or rounded spots (sori), of a red colour; and on close examination, the spots appear dotted with yellow points. Each point is the orifice of an open capsule (peridium), which has burst through the epidermis of the leaf ([Pl. VII.] fig. 9 p). The capsules are split or lacerated at the margins, and form little cups containing the spores. The spores are very minute, yellow, and are arranged in closely packed moniliform rows. The red colour depends upon the altered chlorophyll of the leaf. On the leaves containing the spore-capsules or peridia will be found smaller, brownish-yellow capsules (spermogonia) partly imbedded in their substance ([Pl. VII.] fig. 9 s). These contain minute filaments (sterigmata), terminated by short rows of rounded cells (spermatia), which are supposed to exert an antheridial function. The species of Æcidium are very numerous, and many of them are extremely common—as those upon the nettle, the barberry, the dandelion, the wood-anemone, the violet, and buttercups. The groups of capsules form exquisite opake objects under a low power of the microscope.
Phragmid´ium bulbósum ([Pl. VII.] fig. 14) is another very beautiful coniomycetous Fungus. It forms little reddish, afterwards sooty dots upon the under surface of the leaves of various species of Bramble (Rúbus). The oblong spores (fig. 15) are from 2-to 4-septate, and stalked, the stalks being swollen or bulbous at the base. The spores, which appear brown when magnified, are covered with little knobs (tuberculate) on the surface; and the uppermost little spore or sporidium is terminated by a minute point (apiculate). Among the spores are numerous barren filaments or paraphyses.
Puccin´ia gram´inis ([Pl. VII.] fig. 16) is to be found everywhere upon damp rotting straw, and upon grasses. It forms sooty irregular streaks, consisting of densely crowded, one-partitioned (uniseptate) spores (fig. 17), which appear brown under the microscope. This Fungus is sometimes called “mildew.” There are numerous other species of Puccinia which occur upon common plants.
Urédo seg´etum is the “smut” of wheat, barley, and oats—a fungus too well known to the farmer. It forms sooty masses, bursting through the epidermis of the stalk and ears of the corn, and soiling the fingers when handled. The spores ([Pl. VII.] fig. 5) are exceedingly minute, and the stalks are so slender and loosely connected with them that they are not readily detected. Under the microscope the spores appear brown and faintly dotted, this appearance arising from a reticulated structure of the surface, similar to that of the poppy-seed on a very small scale.