246 SCIENCE PROGRESS. 



frond became covered with prothalli developed not merely 

 from the edges, but also from the upper surface, and being- 

 pegged down produced a number of plants, but whether 

 apogamously or not I cannot say, though from De Bary's 

 observations, they should be so. It is worthy of remark 

 that in some of these youngsters, the line between the two 

 generations of sporophore and oophore was so vague that 

 the primary fronds were simply stalked prothalli, the next 

 frond half one and half the other, while the fourth or 

 fifth had quite outgrown the tendency and were of the 

 typical varietal form. This plant was exhibited and de- 

 scribed at the Linnean Society, 3rd November, 1892. 1 Of 

 the next two cases I observed, the first was an Athyrium 

 found in Lancashire and exhibited in 1893 at the meeting 

 of the Pteridological Society at Lancaster by Mr. Bolton 

 the finder. Immediately on seeing it I remarked, "How 

 very like Col. Jones's Clarissima," simultaneously with which 

 Mr. Bolton said, " It is strange, but it never ripens its 

 spores " ". Turning the frond over, the reason was clear, 

 it was perfectly white with aposporal excrescences. On 

 submitting these to culture they produce plants freely by 

 sexual action, but of two types, one very depauperate, mere 

 skeleton plants, and the other of the parental form with 

 occasional reversion towards the normal. In some of these 

 young plants the whitish excrescences are plentiful in 

 fronds only an inch or two high, and there are evident 

 signs of prothalloid growth at the tips of the segments as 

 well, pointing to apical apospory when the plants are more 

 developed. The next case occurs in a most unlikely species, 

 especially as apical apospory is in question. This is seen 

 in a variety of Scolopendrium vulgare (S. v. cri spurn 

 DrummondicB) which occurs in the wild state, like all the rest, 

 characterised by being frilled and crested, and having more- 

 over a finely fimbriated edge to the fronds. Visiting Mr. 

 Bolton to inspect the Athyrium last cited, I saw a fine plant of 

 this fern, and it immediately struck me that the tips of 



lu Notes on an Aposporous Lastrea (Nephrodium)" Linn. Soc. Journal 

 Botany, vol. xxix., pp. 479-82. 



