48 



STATE HORTICULTURAL SOCIETY. 



in., they have on the outside of their comparatively thick wall, a vast number 

 of little protuberances, which serve to distinguish this species. It is by reason 

 of this thick wall that the spore is enabled to withstand much exposure to the 

 weather without becoming injured. As the plant can, through its spores, tide 

 over a drouth or the cold of winter they are called resting pores. For illustra- 

 tions consult figure 23. 



Dr. Beal : In the absence of L. C. Colburn I will say a few words concerning 

 his drawings and the subject upon which he was to speak, viz. : the common 

 bread mould. Mucor mucedo. The illustrations are shown in Figs. 24 and 25. 



Fie. 24. 



Fig. 25. 



As this fungus, like others, feeds on materials all ready to nourish it, it can 

 grow with great rapidity. A spore, answering to a seed, drops upon damp 

 bread and very soon puts out a tube which creeps over the surface or penetrates 

 the mass, absorbing food and enlarging as it goes on. 



After the threads, called mycelium, have become numerous and well estab- 

 lished they send short stalks upward called hyphce. At the top of each hypha 

 is developed a cell which enlarges and is called a sporangium. This is first 

 light colored and then becomes black. Each one contains from 1,000 to 2,000 

 spores. Later on in the growth of the fungus, when it has partially exhausted 

 the supply of moisture as food, two branches of the fungus meet, the wall be- 

 tween them separates and a thick -walled spore is produced. This is a resting 

 spore, and is so hardy that it is capable of living over many weeks and endur- 

 ing many hardships. No mould will be developed if the supply of air is well 

 cut off as in canned fruit. 



Mr. F. H. Hall had some good drawings, but the subject was one not adapted 

 to this meeting. He has prepared himself to recite, mainly from Bessey's bota- 

 ny, a part of one chapter on the effect of heat or cold on the cells and their 

 contents. 



F. H. Hall : When the temperature rises above a certain point, the death of 

 the plant takes place. Those plants, or parts of plants, which contain the least 

 water are capable of enduring higher temperature than those which are more 

 watery. Thus, at from 149° to 177° Fahr., many dry spores and seeds are un- 

 injured, while in water they are generally killed when the temperature exceeds 

 122° or 131° Fahr. The immediate cause of death appears to be the coagula- 

 tion of the albuminoids of the protoplasm. The protoplasm thus loses its 

 power of imbibing water, and the cells, consequently, lose their turgidity. In 

 watery tissues chemical changes at once begin, resulting in the rapid disinte- 

 gration of the substances in the cells, accompanied by an evolution of carbon 

 dioxide. 



