Elements of Structural and Systematic Botany

FUNGI (My

ugh them with the alg?, the greater number differ very strongly from all green plants both in their habits and in their structure and reproduction. It is a much-dispu

s of alcoholic fermentation; these are the yeast fungi (Saccharomycetes). They cause the fermentation of beer and wine, as well a

in a short time bubbles of gas will make their appearance, and after a little longer time alcohol

A careful examination with a strong lens (magnifying from 500–1000 diameters) shows that the protoplasm, in which are granules of varying size, does not fill the cell completely,

d or at the side of the cell, and enlarges rapidly, assuming the form of the mother cell, from which it becomes completely separated by the constriction of the base, and may fall off at once,

st. B, C, similar cells, showin

wn in much the same way that bacteria are shown to cause ordinary decomposition. L

ly settled, the question being whether they are to be regarded as independent plants or only one stage in the life hi

e Smuts (Us

culty in germinating them, the plants are very difficult of study, except in a general way, and we will content ourselves with a glance at one of the common forms, the corn smut (Ustillago

cilaginous (Fig. 38, B). The ends of these short branches enlarge rapidly and become shut off by partitions, and in each a globular spore (Fig. 38, C) is produced. The outer wall is very dark-colored and provided with short

s of the fungus from a thin section of a diseased grain, showing the b

s sometimes growing as large as a walnut. As the spores ripen, the affected parts, which are at first white, become a livid gray, due to the black spores shining thro

ased upon the arrangement of the spores. The first of these is known as the Asco

scomycetes

ci, sing. ascus) that are usually oblong in shape, and each containing eight spores, although the number is not alw

the student. In these the spore sacs are borne directly upon the filaments without any protective covering. The only form that

e sacs contained in special structures called spore fruits, that may reach a d

n, they may be readily obtained, and are easily studied. One of the best species for study (Podosph?ra) grows abundantly on the leaves of the dandelion, especially when the plants are growing under unfavorable conditions. The same species is also found on other plants of the same family. It may be found at almost any time during the

fruit, × 300. ar. archicarp. G, a ripe spore fruit, × 150. H, the spore sac removed from the spore fruit, × 150. I, spore-bearing filament a

e, in which it should be carefully spread out with needles. If air bubbles interfere with the examination, they may be driven off with alcohol, and then the cover glass put on. If the specimen is mounted in glycerine, it will keep indefinitely, if care is taken to seal it up. The plant consists of much-interlaced filaments, divided at intervals by cross-walls.[6] They are nearly colorless, and the contents are not conspicuous. These filaments send up vertical branches (Fig. 39, A), that become div

kers (h) by which the filaments are attached to the leaf.

icarp," is somewhat larger than the other and nearly oval in form, and soon becomes separated by a partition from the filament that bears it. The other branch (antheridium) grows up in close contact with the archicarp, and like it is shut off by a partition from its filament. It is more slender than the archicarp, but otherwise differs little from it. No actual communication can be shown to be present between the two ce

d the two cells of the archicarp. The spore fruit now enlarges rapidly, and the outer cells become first yellow and then dark brown, the walls becoming thicker and harder as they change color. Sometimes special filaments or appendages grow out from their outer surfaces, and these are also dark-colored. Shortly before the fruit is ripe, the upper cell of th

B, cluster of spore sacs of the same, × 150. C, a single appendage, × 300. D

the mildew. They usually appear at the base of the chains of conidia, causing the basal cell to enlarge to many times its original size, and finally kill the young conidia, which shrivel up. A careful examination reveals the presence of very fine filaments within those of th

ascus in the spore fruit; and Erysiphe, with two or more. In the latte

e often very beautiful in form, and the two genera given above

en allowed to remain damp, and is also very common on botanical specimens that have

way in which the spores are borne-optical section-× 150. D, spore fruit of the herbarium mould, × 150. E, spore

which are enlarged at the end, and from which grow out little prominences, which g

e visible to the naked eye as little yellow grains (Fig. 42, D). The

iffering in color and size, some being yellow or

is the blue mould (Penicillium). This, in general appearance, resembles almost exactly the

or the black moulds, in dilute glycerine; but must be handled with

rms is often of considerable size, and, as their name indicates, is open, having the form of a flat disc o

for a week or two, so as to retain the moisture, at the end of this time a large crop of the fungus will probably have made

ges are too small to be visible to the naked eye. The spore fruits arise from filaments not unlike those of the mildews, and are preceded by the formation of an archicarp composed of s

are special sterile filaments developed between them. If the young spore fruit is treated with chlor-iodide of zinc, it i

ng spore sacs. D, section through a full-grown spore fruit (partly diagrammatic), × 25. sp. spore sacs. E, development of spore sacs and sp

rm as many oval masses, each of which develops a wall and becomes a spore (Figs. ii–iv). These are imbedded in protoplasm, which is at first granular, but afterwards becomes almost transparent. As the spores ripen, the wall acquires a beautiful violet-purple color, changing later to a dark purple-brown, and marked with irregular longitudin

They are sometimes bright scarlet or orange-red, and very showy. Another curious form is the morel (Morchella), common in the spring in dry

Lich

fences, etc., and are found pretty much the world over. Among the commonest of plants are the lichens of the genus Parmelia (Fig. 44, A), growing everywhere on tree trunks, wooden fences, etc., forming gray, flattened expansions, with much indented and curled margins. When dry, the plant is quite brittle, but on moistening becomes flexible, and at the same time mor

ough the body of a gelatinous lichen (Collema), showing the Nostoc individuals surrounded by the fungus filaments, × 300. D, a spermagonium o

color, two or three millimetres in diameter, and closely resembling a small cup f

e plant these are rather loose, but toward the outside become very closely interwoven and often grown together, so as to form a tough rind. Among the filaments of the outer portion are numerous small green cells, that closer examination

uch the same, usually, though not always, containing eight spores, which are sometimes two-celled. The sterile filaments between

g?, upon which the lichen is parasitic, surrounded by some of the filaments, t

of the lichens is often difficult to study, and free use of c

cta, one-half natural size. D, Peltigera, one-half natural size. ap. spore fruit. E, a single spore fruit, × 2. F, Cladonia, natural size.

s, is a familiar example; of the second, Parmelia, Sticta (Fig. 45, C) and Peltigera (D) are types; of the third, Graphis (G), common on the trunks of beech-trees, to which it closely adheres; and of the last, Collema (Fig. 44, C, D, E),

lum-tree attacked by b

onia (Fig. 44, D), are found, in which excessively small spores are produced, which have been

by producing their spore sacs in closed cavities. Some are parasites; others live on dead wood, leaves, etc., forming very hard masses, generally black in color, giving them their common name. Ow

more or less used in medicine. Other forms are known that attack in