84 



STATE HORTICULTURAL SOCIETY. 



It was formerly thought that all 

 organisms possessing the power of 

 motion, and especially of locomo- 

 tion, were animals; but it is now 

 known that many forms that are 

 essentially, in structure, plants, 

 possess this power, and no atten- 

 tion is now given to motion as a 

 distinctive animal attribute. 



The slime moulds (Fig. 1, ' to 

 ") consist of cells, either single or 

 joined together, forming large, jelly- 

 like masses. During their growing 

 period they have no cell walls, being 

 a mere naked mass of iDrotoplasm, 

 and are without nuclei. When 

 they have reached their growth 

 they break up into smaller masses, 

 each of which secretes a covering 

 wall of cellulose for itself, and they 

 then assume what is known as a 

 resting stage. Any unfavorable 

 surroundings, as a lack of moisture 

 or a proper temperature, will cause 

 the same behavior. When condi- 

 tions become favorable they resume 

 their former soft form; but, if 

 ready for reproduction before becoming encysted, the interior of the 

 masses break up into a number of small bodies, each of which forms a cell 

 wall. These are the spores, and if exposed to proper conditions of tem- 

 perature and moisture they burst their coverings and take on a ciliated or 

 amoeboid form. 



In the former case they are provided with one or two hair-like appen- 

 dages, and it is generally assumed when the amount of moisture is 

 sufficient to enable them to swim. 



In the amoeba-like form they often reach a considerable size and are 

 able to crawl about. 



These plants generally feed on decaying vegetable matter, and the only 

 form known to be particularly injurious to the horticulturist is the one 

 causing club-root in cabbages and turnips. Rapidly increasing by fission, 

 the jelly-like mass swells the roots to many times their normal size, and 

 not only robs them of their sustenance, but so checks the vital actions as 

 to destroy the plants. 



In England and on the continent, where club-root often occurs, they 

 never grow turnips, cabbages, or other cruciferous crops on the land 

 oftener than once in three years. The diseased roots are also gathered 

 and burned. 



Fig. 1.— Myxomtoetes. 



1. Resting stage of spore. 



2. Rnpture of the spore case. 

 4-5. Ciliated zoospores. 

 6-10. Amceboid forms. 



11. Plasmodium.— ^/terDe -Bar J/. 



BACTERIA. 



Standing just above the slime-moulds in the vegetable kingdon, but 

 bearing little or no resemblance to them, is a family of microscopic plants 

 commonly known as bacteria. (Fig. 2.) 



