372 ON THE STUDY OF MICRO-FUNGI. 



a germ tube has begun to issue from each of the ripe secidiospores, 

 and this tube will continue to grow until many times the length of 

 the spore from which it arises. Some of the tubes will become 

 much bent and curved about from side to side, and the coloured 

 protoplasm will be seen to leave the spore and flow slowly along 

 the tube until it reaches the end. Soon all the protoplasm will 

 have travelled along the germ tube, and the spore will be left quite 

 empty. The tube may become branched, and the protoplasm will 

 flow into the branches. Plate XVII., Fig. 3, represents a ger- 

 minating secidiospore. 



Now that which takes place on the glass slide takes place also 

 on the Nipplewort. We have already stated that the spores 

 become scattered about, not only on the host plant itself, but also 

 on the surrounding vegetation ; when, therefore, there is a shower 

 of rain or fall of dew, these spores begin to germinate precisely in 

 the same way as we saw them do in the experiment ; but 

 the process goes further, for the ends of the germ tubes, or of the 

 branches of those spores which happen to be upon a leaf of the 

 Nipplewort, enter through the stomata into the tissues of the leaf, 

 and there develop, finally producing a fresh mycelium. The 

 empty spores and the portions of the tubes remaining outside the 

 leaves then fall off and disappear, as their mission is ended. 



It must, of course, be borne in mind that, although all the ripe 

 secidiospores germinate when moisture is applied, it is only those 

 which are in touch with the proper host plant that enter the stomata 

 and give rise to a mycelium. The spores may have germinated in 

 hundreds on some neighbouring plant, but without producing the 

 slightest eflect. If we secure a few specimens of Lapsa?ta com- 

 mimis^ and also of some other plants, all of w^hich should be free 

 from any traces of fungus, we can easily test the accuracy of what 

 has just been stated. One or more leaves of the Lapsana should 

 be well moistened and some freshly gathered aecidiospores brushed 

 on to the wet surfaces. The plant ought then to be covered with a 

 globe for a day or two, so as to keep the leaves damp and afford 

 the spores an opportunity to germinate. If at the same time that 

 this is done we also inoculate some other plants, say the Daisy or 

 the Nettle, and in addition preserve a Lapsana from all contact 

 with any aecidiospores, they will help us to understand the process, 

 and will serve also as a check. 



