FERN GROWING 37 



case with undivided prothalli, but up to July 1890 there was 

 no sign of any frond. It appeared evident that the male and 

 female organs of generation were on separate divisions. To 

 test this, in May 1890 another prothallus was planted in 

 close proximity to one of these, in fact made to actually 

 intermingle, and in August fronds appeared. The other 

 divisions, except four, were similarly treated, and all have now 

 produced fronds. The spores had been sown on August 1887, 

 and divided on January 12th, 1888, so that the prothallus 

 exhibited has been in this condition four years. The usual 

 time from prothallus to frond being only a few months. 



" In an interesting example of the Lady Fern (alluded to 

 in the next paper), a prothallus produced three plants exactly 

 alike and having two kinds of fronds. It was from a mixture 

 of eight varieties, and these show the parentage of six, and 

 now and then seven. They have the lax pinnae of uncum, 

 the cruciate pinnae of Victories, the projected pinnae of pro- 

 jectum, the lunulate pinnules of FrizellicB, the cruciate pinnules 

 of crucipinnulum, the truncate terminals of truncatuin, and occa- 

 sionally the cresting of multifidum. This Fern has reproduced 

 six and occasionally seven characters. According to the 

 doctrine of probability, it is 720 to i against the production 

 of six varieties on the same plant, and 5040 against seven. 



" Turning to other means of reproduction, experiments are 

 required in order to ascertain why the bulbils that form on 

 some fronds do not always produce plants like the parents, 

 and why it is possible to transfer the bulb-bearing character 

 to other varieties. Scolopendrium densum often produces much 

 more coarse and less-divided Ferns than itself A. angulare 

 plumoso-divisilobum var. densum has produced two plants from 

 its bulbils that are strikingly distinct from the parent and 

 each other ; one is densely imbricate and procumbent like 

 the parent ; whilst the other is as finely divided as Todea 

 superba, and is erect in habit. Again aposporous plants, 



