Part 8 (2/2)

_Pyrenomycetes_, represented by the black knot of cherry and pluuished fro their spore sacs in closed cavities Some are parasites; others live on dead wood, leaves, etc, for the to the hardness of the masses, they are very difficult to manipulate; and, as the structure is not essentially different from that of the _Discomycetes_, the details will not be entered into here

Of the parasitic forot” of rye, more or less used in medicine Other forms are known that attack insects, particularly caterpillars, which are killed by their attacks

CHAPTER X

FUNGI--_Continued_

CLass _Basidioest andwhich are many familiar forms, such as the e and familiar for to the latest investigations, are probably related to theroup The enerally known of these lower _Basidioer _Basidio vegetable matter, but a few are true parasites upon trees and others of the flowering plants

All of the group are characterized by the production of spores at the top of special cells known as basidia,[8] the nule one to several

[8] Sing _basidium_

Of the lower _Basidiomycetes_, the rusts (_Uredineae_) offer common and easily procurable forms for study They are exclusively parasitic in their habits, groithin the tissues of the higher land plants, which they often injure seriously They receive their popular name from the reddish color of the h the epideri, the rusts have several kinds of spores, which are often produced on different hosts; thus one kind of wheat rust lives during part of its life within the leaves of the barberry, where it produces spores quite different from those upon the wheat; the cedar rust, in the sa the leaves of the wild crab-apple and thorn

[Illustration: FIG 47--_A_, a branch of red cedar attacked by a rust (_Gy a so-called ”cedar apple,”_B_, spores of the saer a short, divided filaives rise to secondary spores (_sp_), 300 _D_, part of the leaf of a hawthorn attacked by the cluster cup stage of the saonia, natural size _E_, cluster cups (_Roestelia_) of the saus, natural size _F_, tip of a leaf of the Indian turnip (_Arisaee of a rust, 2 _G_, vertical section through a young cluster cup _H_, si spores of _H_, 300 _J_, part of a corn leaf, with black rust, natural size _K_, red rust spore of the wheat rust (_Puccinia graminis_), 300 _L_, forms of black-rust spores: i, _Uromidium_]

The first form met with in e, and in ure 47, _F_, is shown a bit of the leaf of the Indian turnip (_Arisaema_) affected by one of these ”cluster-cup” fornified, the e spots, mostly upon the lower surface The affected leaves are rowth, and the upper surface shows lighter blotches, corresponding to the areas below that bear the cluster cups These at first appear as little elevations of a yellowish color, and covered with the epiderh the epider, the whole fore red powder, co a piece of the affected leaf between two pieces of pith so as to hold it firmly, with a little care thin vertical sections of the leaf, including one of the cups, lycerine, re the air with alcohol We find that the leaf is thickened at this point owing to a diseased growth of the cells of the leaf, induced by the action of the fungus The47, _G_) is surrounded by a closely woven lobular cavity Occupying the botto a row of spores, arranged like those of the white rusts, but so closely crowded as to be flattened at the sides The outer rows have thickened walls, and are grown together so as to forranular protoplase-yellow oil, to which is principally due their color As the spores grow, they finally break the overlying epidermis, and then becoer out a tube, into which pass the contents of the spore (Fig 47, _I_)

One of the iurowths known as ”cedar apples,”

often met with on the red cedar These are roundedupon the srowth of the same nature as those produced by the white rusts and smuts If one of these cedar apples is examined in the late autumn or winter, it will be found to have the surface dotted with little elevations covered by the epider spores These rupture the epider, and appear then as little spikes of a rusty red color If they are kept wet for a few hours, they enlarge rapidly by the absorption of water, and elatinous in consistence, and so the surface of the ”apple” In this stage the fungus is extremely conspicuous, and

This orange jelly, as shown by the ated two-celled spores (teleuto spores), attached to long gelatinous stalks (Fig 47, _B_) They are thick-walled, and the contents resemble those of the cluster-cup spores described above

To study the earlier stages of germination it is best to choose specimens in which the hly wetting these, and keeping erroithin twenty-four hours or less Each cell of the spore sends out a tube (Fig 47, _C_), through an opening in the outer wall, and this tube rapidly elongates, the spore contents passing into it, until a short filament (basidium) is formed, which then divides into several short cells Each cell develops next a short, pointed process, which swells up at the end, gradually taking up all the contents of the cell, until a large oval spore (_sp_) is for all the protoplas that these spores do not germinate upon the cedar, but upon the hawthorn or crab-apple, where they produce the cluster-cup stage often ht orange-yellow spots about a centi 47, _D_), and considerably thicker than the other parts of the leaf On the upper side of these spots may be seen little black specks, whichthose of the lichens Later, on the lower surface, appear the cluster cups, whose walls are prolonged so that they for 47, _E_)

In most rusts the teleuto spores are produced late in the su before they ger dark-colored, so that in mass they appear black, and constitute the ”black-rust” stage (Fig 47, _J_) associated with these, but for ile-celled spores, borne on long stalks They are usually oval in form, rather thin-walled, but the outer surface sometimes provided with little points The contents are reddish, so that in mass they appear of the color of iron rust, and cause the ”red rust” of wheat and other plants, upon which they are growing

The classification of the rusts is based mainly upon the size and shape of the teleuto spores where they are known, as the cluster-cup and red-rust stages are pretty enera _Mela 47, _L_ i), have unicellular teleuto spores; _Puccinia_ (ii) and _Gymidium_ (iii), four or more

The rusts are so abundant that a little search can scarcely fail to find soes are best examined fresh, or from alcoholictheroup is the wheat rust (_Puccinia grae to wheat and soe may be found in early summer; the black-rust spores in the stubble and dead leaves in the autu the epidermis

Probably to be associated with the lower _Basidio 51, _A_) is an example They are jelly-like for soft when s, etc, and are usually brown or orange-yellow in color

Of the higher _Basidiohest, and any common form will serve for study One of the most accessible and easily studied for on the excrement of various herbivorous animals They not infrequently appear on horse lass for some time, as described for _Ascobolus_

After two or three weeks soi are very likely to make their appearance, and new ones continue to develop for a long tirown fruit of a toadstool (_Coprinus_), 2 _C_, under side of the cap, showing the radiating ”gills,” or spore-bearing plates _D_, section across one of the young gills, 150 _E_, _F_, portions of gills from a nearly ripe fruit, 300 _sp_ spores _x_, sterile cell In _F_, a basidiu _G_, _H_, young fruits, 50]