A RACE OF FLOWERLESS PLANTS. 



277 



similar, but their]^structure is different. The spores are 

 borne externally. A'special cell has four prongs at the 

 tip, each bearing a spore. At maturity 

 the end of the cell is shot off, carrying 

 the spores with it. Professor T. H. Mc- 

 Bride records a case in which the spores 

 were projected two or three feet in all di- 

 rections. He thinks the hymenial layer 

 must be hygroscopic. The same observer 

 speaks of the ejection of the spores of 

 slime-molds from some cause not under- 

 stood. 



There is another class of fungi which 

 live in water, and among^them is the Sa- 

 prolcgiiia, which sometimes causes an ep- 

 idemic among fishes, notably salmon, 

 called the " salmon disease. " The spores 

 themselves have the power of motion. 

 They are formed in a long sack-like ter- 

 minal cell (Fig. 3), and are first forced 

 out by a process similar to that already 

 described. Once free, they are seen to 

 have two slender appendages, which vi- 

 brate very rapidly and propel them 

 through the water with a motion resem- 

 bling that of the infusoria. So much for 

 the dispersal of fungi by power in them- 

 selves. 



Fungi also manage to make animals and 

 the forces of nature serve them as other 

 plants do. A man walking through a field 

 of rusted wheat gets his clothes covered 

 with yellow spores, which, [perhaps, ad- 

 here more closely because of the minute 

 ^' spines which cover the surface. Many 

 peculiar molds grow on the excrement of various ani- 

 mals, and are found nowhere else, in many cases not 

 even on the excrement of a related animal. Do their 

 spores germinate only after passing through this partic- 

 ular animal, or are they lying about, able to grow only 

 on that particular kind of excrement ? Perhaps insects 

 carry the viscid secretions of pear-blight and other sub- 

 stances containing bacteria. It is even suggested that 

 the bad odors accompanying putrefaction are designed 

 to attract insects. Some think, apparently with good 

 reason, that pear-blight enters the tree through the 

 blossoms. Is the virus carried 

 to the blossoms by insects which 1 

 have first been attracted to the 

 bad-smelling viscid secretions of 

 a diseased tree ? 



A recent writer in the Annals 

 of Botany has taken great pains 

 to show that the large stink-horn 

 fungi have their spores carried by 

 insects, and are especially con- 

 structed with this object in view. 

 He convinced himself by observation that this was the 

 case in the common species, and then reviewed the va- 

 rious species growing in all parts of the world to show 



Fig. 



Fig. 



the special adaptation of the group as a whole. He 

 shows that the spores are enclosed and protected until 

 maturity, when the plant rapidly expands, not by growth, 

 but by mechanical means, being released from confine- 

 ment, reaching 

 a height of sev- 

 eral inches in 

 about two 

 hours, and this 

 at a favorable 

 time of day. 

 Thus the plants 

 are not liable 

 to be destroyed 



by other animals or by accidents before insects visit 

 them. Ninety-six per cent, of the species are bright 

 colored, as compared with twenty-five per cent, of other 

 fungi and seventy-three per cent, of flowers. Three- 

 fourths of the species have the fetid odor. 



While speaking of insects, we should not forget the 

 case of earth-worms bringing up the germs of charbon 

 or anthrax from a buried animal, and thus communicat- 

 ing the disease to cattle eating grass from the spot. 



A smoking lamp fills the air of a room with particles 

 of soot which may float as far as an adjoining room, and 

 are large enough to be seen as they slowly settle. Par- 

 ticles which compose a cloud of dust driven by the wind, 

 and even particles of dust about the house, are plainly 

 visible separately when they settle. Having this in 

 mind, we cannot question for a moment the ease with 

 which spores of a puff-ball or of corn smut, too small 

 to be seen separately, may float in the air or be carried 

 long distances by the 

 wind. The same is true 

 of the spores of many 

 other fungi, including 

 some of those which for- 

 cibly eject their spores, 

 mushrooms for example. 



Wheat-rust, whose 

 winter spores remain at- 

 tached to the straw, pro- 

 duce a kind of secondary 

 spores (Fig. 7) which are 

 adapted to being thus 

 transported. The same 

 is true of the cedar-ap- 

 ples (see March number, 

 p. 137, Fig. 2). For the 

 propagation of some 

 fungi the presence of two 

 different flowering plants 

 may be necessary, as in 



the case just mentioned, where one stage of growth is on 

 the apple tree, the other on the cedar. There should be 

 no apple-rust where there are no cedar trees. A disease 

 in a given plant may be kept alive from year to year by 

 allied wild plants which harbor the fungus, as grape 

 mildew on Virginia creeper. The spores of many par- 

 asitic species remain for a time, at least, attached to the 



Fig. 6. 



