Urédo cáries is the “bunt” of corn. It grows within the grain, filling it with a sooty, fœtid mass. The spores ([Pl. VII.] fig. 6) are considerably larger than those of the last species, and their surface is distinctly reticulated. They are attached to the filaments of the mycelium, as in Uredo segetum.
The spores of both these species of Uredo may be found in most kinds of flour and bread, especially in those of inferior quality.
Urédo can´dida ([Pl. VII.] fig. 7) is another species, forming white dots upon the leaves of the common Shepherd’s Purse (Capsel´la bur´sa pastor´is)—which is easily recognized by the form and arrangement of the pods (fig. 19). The spores (s) are rather large and white.
Other species of Uredo are very common upon numerous species of weeds or wild flowering plants; and they so closely resemble each other that, when one is known, the others are easily recognized. Usually each species occurs upon a distinct species of plant, as is the case with parasites generally. In many of them the spots (sori) exhibit a thin membrane covering the spores, which bursts down the middle, so as to bear some resemblance to a capsule. But there is no true capsule, the membrane consisting of the epidermis of the leaf or stalk of the plant, which is raised and torn by the expansion of the growing fungus; so that the peridium is spurious, as belonging to the matrix, and not to the fungus. It may be mentioned here that the so-called species of Uredo are not truly distinct species, but are the forms of species of Puccinia, Phragmidium, &c.; so that the latter genera have two kinds of fruit, one of which is a Uredo, the other a Puccinia. But I must refer to the Dictionary for further details upon this point.
Hyphomyce´tes (ὑφἁω, to weave, μὑκης, fungus). In this, the 4th Order of Fungi, are contained many of the commonest moulds which are found growing upon decaying substances, and sometimes upon living plants. The mycelium creeps among the particles of the substance, or the elements of the tissues, upon which the Fungus lives, in the form of slender threads or filaments. The spores, which are either simple or partitioned (septate), and naked, occur either singly or in rows at the ends of fine interwoven cottony threads or floc´ci (floc´cus, a flock of wool), which are generally very evident to the naked eye. The threads supporting the spores form the ped´icels (pedicel´lus, a little foot). In technical descriptions, these filaments, which are usually composed of cells arranged end to end, are said to be septate (Pl. VII. fig. 26), and not jointed, as in the case of the filaments of the Confervæ, which are constructed in a similar manner. When not septate, the filaments are said to be continuous.
Stilba´cei.—To this family belongs Tuberculária vulgaris ([Pl. VII.] fig. 28), which is found upon decaying sticks and branches of trees, especially the lime-tree. It forms little firm red knobs or tubercles, each of which is a receptacle. On making a section of a receptacle (Pl. VII. fig. 29), the interior is seen to be paler than the bright red surface, and a short broad stalk comes into view. The receptacle is composed of crowded cell-filaments, so short near the base as rather to resemble cellular tissue (fig. 30); but towards the surface the filaments become extremely slender and branched; and each branch is terminated by a minute oblong spore, or a short row of them (fig. 31).
If a stick with this Fungus upon it be kept for some time in a damp place, short whitish fibres, branched at the ends, and visible to the naked eye, will be seen sprouting from around the base of the receptacle ([Pl. VIII.] fig. 1). These, when examined under the microscope, appear composed of fine filaments ([Pl. VIII.] fig. 2), resembling those of Tubercularia, and having the minute spores at the ends. After a considerable time, the entire receptacle of the Tubercularia becomes resolved into these fibres. In this state the Fungus assumes the characters of an Isária, a genus of a different family of Fungi (Isariacei), so that we have here an Isaria-form of Tubercularia.
Sometimes the tubercles of the Tubercularia become darker, almost black, harder, and granular on the surface. On making a section of them in this state, the whole of the under portion of the surface is found to contain little roundish capsules, containing asci and spores, and it constitutes Sphæ´ria fragifor´mis ([Pl. VII.] fig. 32). As the Sphæria is the more complex and highly organized condition of this Fungus, the other two conditions must be regarded as forms, and not as species of separate genera.
Dematie´i.—In this family the filaments upon which the spores are placed are not compacted as in Tubercularia, but separate; and they are of a dark brown or black colour.
Sporoc´ybe alternáta ([Pl. VII.] fig. 18) is occasionally found upon decaying vegetable substances, forming little black velvety spots or patches. The mycelial filaments are exceedingly minute, septate, tapering at the ends, and terminated by a little tuft of pear-shaped cells, from which the black simple spores arise singly.