Part 6 (1/2)

[Illustration: FIG 31--Fresh-water red algae _A_, _Batrachospermum_, about 12 _B_, a branch of the saenera are _Batrachosper 31)

CHAPTER VIII

SUB-KINGDOM III

FUNGI

The nae of plants, varyingthemselves, but on the whole of about the saae, however, they are entirely destitute of chlorophyll, and in consequence are dependent upon organic anis on dead matter) Soae, and there is reason to believe that they are descended froinally had chlorophyll; others are very different froh nizing then these distinctions, we i (_Phycoi (_Mycomycetes_)

CLass I--_Phyco, undivided, often branching tubular fila quite closely those of _Vaucheria_ or other _Siphoneae_, but always destitute of any trace of chlorophyll The simplest of these include the common moulds (_Mucorini_), one of which will serve to illustrate the characteristics of the order

If a bit of fresh bread, slightly moistened, is kept under a bell jar or tumbler in a warm room, in the course of twenty-four hours or so it will be covered with a film of fine white threads, and a little later will produce a crop of little globular bodies ht stalks These are at first white, but soon becorow dark-colored

These are rown fro on the bread, which offers the proper conditions for their growth and multiplication

One of the co 32), and named _Mucor stolonifer_, from the runners, or ”stolons,” by which it spreads frorows it sends out these runners along the surface of the bread, or even along the inner surface of the glass covering it They fasten themselves at intervals to the substratum, and send up from these points clusters of short filaium”

For lycerine (about one-quarter glycerine to three-quarters pure water) After carefully spreading out the specimens in this mixture, allow a drop of alcohol to fall upon the preparation, and then put on the cover glass The alcohol drives out the air, which otherwise interferes badly with the exa, much-branched, but undivided tubular filament Where it is in contact with the substraturowths are formed, not unlike those observed in _Vaucheria_ At first the walls are colorless, but later becoranular protoplas tips of the branches The spore cases, ”sporangia,” arise at the ends of upright branches (Fig 32, _C_), which at first are cylindrical (_a_), but later enlarge at the end (_b_), and become cut off by a convex wall (_c_) This wall pushes up into the young sporangiurown, the sporangiu to the nu the space between the colureat nu to a thick, black wall formed about each one, and at the saium becoiu 32, _E_) are set free The colued, and so 32, _D_)

[Illustration: FIG 32--_A_, common black mould (_Mucor_), 5 _B_, three nearly ripe spore cases, 25 _C_, development of the spore cases, i-iv, 150; v, 50 _D_, spore case which has discharged its spores _E_, spores, 300 _F_, a form of _Mucor mucedo_, with small accessory spore cases, 5 _G_, the spore cases, 50 _H_, a single spore case, 300 _I_, developospore of a black mould, 45 (after De Bary)]

Spores for those of the pond scurown for a long ti 32, _I_)

Another co in company with the one described, differs froiu runners This species soia attached to the32, _F_, _H_)

These sia have no columella

Other er species of _Mucor_

Related to the black moulds are the insect moulds (_Entomopthoreae_), which attack and destroy insects The commonest of these attacks the house flies in autu topanes, and surrounded by a whitish halo of the spores that have been thrown off by the fungus

ORDER II--WHITE RUSTS AND MILDEWS (_Peronosporeae_)

These are exclusively parasitic fungi, and groithin the tissues of various flowering plants, soroup ill select a very common one (_Cystopus bliti_), that is always to be found in late su weed (_Amarantus_) It forms whitish, blister-like blotches about the size of a pin head on the leaves and ste 33, _A_) In the earlier stages the leaf does not appear much affected, but later becous

If a thin vertical section of the leaf is h one of these blotches, and mounted as described for _Mucor_, the latter is found to be composed of a mass of spores that have been produced below the epiderrowth If the section is a very thin one, we us, and then find it to be coular, tubular, much-branched filaments, which, however, are not divided by cross-walls These filah the intercellular spaces of the leaf, and send into the cells little globular suckers, by us feeds

The spores already mentioned are formed at the ends of crowded fila 33, _B_) They are for constricted, so as to form an oval spore, which is then cut off by a wall The portion of the filament immediately below acts in the same way, and the process is repeated until a chain of half a dozen oralways the last formed When ripe, the spores are separated by a thin neck, and becoermination it is only necessary to place a few leaves with fresh patches of the fungus under a bell jar or tumbler, inverted over a dish full of water, so as to keep the air within saturated withcare to keep the leaves out of the water After about twenty-four hours, if some of the spores are scraped off and erminate in the course of an hour or so The contents divide into about eight parts, which escape from the top of the spore, which at this ti, each mass of protoplasm swims away as a zoospore, with two extremely delicate cilia After a short tier 33, _C_, _E_)