244 SCIENCE PROGRESS. 



down, two apparently normal and full-sized prothalli being 

 the present result. In this case it will be noted that both 

 plants were far removed from the usual site of reproduction, 

 and both in this respect and in their vigorous development 

 are differentiated from previously cited cases of apogamy. 

 The second case alluded to occurred on another prothallus 

 in the same pan, wherein the bulbil developed likewise 

 upon a horn-like excrescence, but on the centre of the upper 

 surface of the prothallus. This bulbil has developed into 

 what is so far a very weakly plant of a different type to the 

 others, but otherwise presenting no special feature. 



Until 1884 the Prothallus had always been regarded as 

 necessarily the offspring of the spore, but in the autumn of 

 1883 a presumed barren variety of Athyrium jilix fcemina 

 {var. C/arisstma) was sent me for examination. For 

 twenty years this plant had been observed to produce an 

 immense number of apparent sori, but no spores were 

 ripened or shed, and no offspring had consequently been 

 raised. Some previous observations on dorsal bulbils, i.e., 

 bulbils associated with the spore heaps in this same 

 species, led me to the opinion that these apparent sori, 

 which consisted of green pear-shaped masses instead of the 

 capsules proper to spores, did not represent bulbils, but 

 some abnormality in the development of the sporangia. 

 To test this I laid down portions of the fronds, and 

 to my intense surprise these pearshaped bodies com- 

 menced at once to grow into prothalli, their tips dilating 

 and spreading, while root-hairs and subsequently both 

 archegonia and antheridia appeared in abundance. I at 

 once gave a note of my observations at the Linnean 

 Society x as demonstrating the development of the prothallus 

 without the agency of the spore. The following season, 

 pursuing my culture, I was able to exhibit a number of 

 plants and such material as satisfied the society of the 

 facts put forward. 2 Prof. F. O. Bower 3 then undertook 



1 " Observations on a Singular Mode of Development in the Lady Fern 

 {Athyrium filix fosmina)" Linn. Soc. Journal Botany, vol xxi., p. 354-7. 



2 " Further notes on ditto,'' ibid., vol. xxi., pp. 358-60. 



3 " On Apospory in Ferns (with special reference to Mr. Charles T. 

 Druery's observations),'' F. O. Bower, ibid., vol. xxi., pp. 360-68. 



