A RACE OF FLOWERLESS PLANTS— IV.* 



HOW FUNGI ARE DISPERSED, WITH HINTS FOR THE CULTIVATOR. 



Animals as a rule have the power of locomotion, 

 at least during some period of life. Plants as a rule 

 have not the power of locomotion at any period of 

 life, the principal exceptions being the adult forms 

 of some water plants, algje, notably diatoms, and 

 reproductive bodies of certain flowerless plants. 

 The species of palms are very local in most cases. 

 The big trees of California are local and liable to 

 become extinct ; but most flowering plants are 

 more or less widely distributed, and many have 

 special adaptations for dissemination, such as the 

 winged fruit of the maple and ash, the barbed 

 prongs of the beggar-ticks, the pulp of the cherry, 

 the aril of the water-lily seed which enables it to 

 float, the down of the thistle, and many others. The 

 power of the touch-me-not to throw its seeds sev- 

 eral feet by means of the elasticity of the pod is 

 especially interesting in this connection. Among 

 cryptogams, fungi are the most numerous and most 

 varied in their forms and adaptations, and may be 

 expected to have the most devices for dissemination. 

 We will consider how the spores of fungi are expelled 

 by internal forces, how they are carried by external 

 forces, how they survive unfavorable conditions, and 

 how they gain entrance into their host plants. 



A large number of fungi have the power of forcibly 

 expelling their spores when 

 ripe and throwing them to a 

 greater or less distance. Some 

 of these are Discomyu-tcs, a 

 group which may be repre- 

 sented to us by a red cup- 

 fungus common on the ground 

 or sticks in the woods. Two 

 different writers in the Boian- 

 ical Gazette for 1883 record 

 that on opening a small box 

 in which some of these fungi 

 had been placed to keep them 

 fresh, the spores were shot out 

 so forcibly as to make a noise. 

 In experiments made by a 

 writer in Science Gossip, not 

 only was a fizzing noise heard, 

 but their activity was excited 

 by blowing on the plant and 

 the spores were showered forth 

 in all directions. These cases 

 are mentioned as if excep- 

 6 and 7 are after De Bary ; Fig. 2 after Pringshe'm 



Fig. 



Fig. I. 



* Figs. i.A.y 



tional, but according to De Bary this is the usual thing in 

 fungi of this class. Figure 2 represents one of the allied 

 Ascoiiivcetes with spores ripe and ready to be discharged 



from the ascus. Figure 

 I is another example of 

 the same process slight- 

 ly modified. Sometimes 

 the spores are thrown 

 upon the leaves of flow- 

 ering plants that hap- 

 pen to be growing near, 

 and in one such case 

 they were taken for a 

 parasite and described 

 as a new species. A 

 remarkable case is that 

 of a supposed disease 

 of roses in a greenhouse. 

 The florist found his 

 roses covered with black 

 specks and sent them to 

 a mycologist for examination. It was observed that the 

 spots could be picked off with a needle ; they were not 

 attached, but simply lying on the leaf. A section showed 

 nothing of the fungus inside the leaf. Upon inquiry, 

 the florist wrote ; "About seven days after the dressing 

 of manure was put on the black speck began to show 

 itself. It was like a little black tick on a drop of water. 

 The surface of the manure was all covered with them, 

 and when the sun would rise in the morning the little 

 bristle-like ball would burst and throw the black tick 

 up. Some were thrown as far as eight feet, but they 

 were very thick at from three to four feet." This was 

 evidently Pilobolns, but the same kind of spores on rose 

 leaves were described by another botanist as a new spe- 

 cies belonging to a different group. Pilohohis is a large 

 mold that grows on horse dung. Its fruiting stalks are 

 terminated by a spore-case in the form of a black cap, 

 which contains the spores. Just below the tip is a large 

 swelling in the hollow stalk, and at maturity this, as 

 well as the spore-case, absorbs water and becomes dis- 

 tended. There is a ring which is weaker than the rest, 

 and here at length a rupture suddenly takes place and 

 the black spore-case full of spores is thrown some dis- 

 tance, as described above. 



A similar thing on a smaller scale occurs in a fungus 

 which grows on flies. Keep watch of the window-panes 

 in autumn, and you will see an occasional dead fly ad- 

 hering to them and surrounded by a white halo. The 

 fly is infested and killed by a fungus which forcibly 

 throws its spores in all directions. They adhere to the 

 glass and form the halo. The process in mushrooms is 

 ; Fig. 3 after HIne, and Fig. 9 after Brefeld. 



