252 JOURNAL OF THE ROYAL HORTICULTURAL SOCIETY. 



plants commencing with the primary frond), and by the 

 advanced stage of development of the first frond of the young 

 plant itself. 



We have now seen that the fern can be developed from the 

 prothallus both sexually and asexually. 



The next discovery, in 1884, was that the prothallus itself 

 could be generated from the fern plant without the agency of 

 the spore, and, as the first instance of this came under my own 

 notice, I will preface its description by describing the slide now 

 before you, as the study of bulbils led up to it. Bulbils are 

 direct asexual reproductions on the spore-bearing generation, 

 though, as we have seen, not confined to it. These are by no 

 means uncommon, and the slide exhibited shows various types, as 

 exemplified in Woodwardia orientalis, Camptosorus rhizophyllus r 

 Athyrium filix fozmina, Scolopendrium vulgare, Polystichum 

 angulare, and last, but not least, Asplenium bulbiferum, which 

 is the most familiar of all. 



The study of bulbils, as I have said, led to the discovery of 

 apospory, since a pinna of A.f.f.clarissima, which apparently bore 

 bulbils, was sent to me for inspection, and on investigation I found 

 the unusual feature present of an indusium, or spore cover, which 

 led me to a different conclusion, viz. that they were some form of 

 transmuted spore-producing energy, and treating them on this 

 assumption I was at once surprised and delighted to find that 

 instead of developing ferns of the second generation, as bulbils 

 always do, they formed prothalli instead. These prothalli then 

 went through the usual functional process, and only then pro- 

 duced ferns, the first result being some three hundred specimens 

 of a fern thitherto unique. Mr. Wollaston then brought forward 

 a specimen of Polystichum angulare bearing prothalli on the 

 points of the frond divisions, so that in a very brief period two 

 classes of apospory were found to exist, soral and apical. Follow- 

 ing up this line of research it has fallen to my lot to discover the 

 same peculiarity in varieties of Lastrea pseudo-mas, another 

 form of P. angulare, a form of Scolopendrium vulgare, and 

 another Athyrium, the particular features of several of these 

 cases being thrown upon the screen for better elucidation. Dr. 

 Stansficld and Mr. E. J. Lowe have also noted some very 

 remarkable cases of this, Mr. Lowe's consisting of Scolopendrium 

 forms, in which the fronds bear the sexual organs, so that the 



