THE UNCOILING FRONDS. 17 



fern. Instead, there appears a peculiar flat, green, heart- 

 shaped body, scarcely a quarter of an inch across, known 

 as \.\IQ prothallium. On the underside of this are borne 

 two sets of organs and finally by a union of their contents, 

 a new fern is produced. It is small wonder that this 

 complicated process was so long a puzzle to investigators 

 of plants. The knowledge of the subject grew very 

 slowly. In 1648 the nature of the sporangia was first 

 made out, and in 1669 the spores themselves were dis* 

 covered. In 1715 Morrison is said to have raised young 

 plants from spores but it was not until 1788 that the 

 office of the prothallium was known and more than 

 thirty years later before its development was observed. 

 Lastly it was not until near the middle of the nineteenth 

 century that the functions of the small organs on the 

 prothallium were discovered. The time required for a 

 fern to come to maturity from the spore is from three to 

 seven years. 



As may be imagined, many dan- 

 gers threaten the young sporeling, 

 and some species have devised vari- 

 ous " short-cuts" by which to avoid 

 the perils that often seem to threaten 

 the very existence of their race. 

 One of the bladder ferns produces 

 spores in abundance and in addition, 

 little bulblets grow from the under 

 surface of the fronds. The spores 



' SORI OF POLY PODIUM. 



are scattered far and wide and may 

 or may not land in a favourable place for germi- 

 nation, but the bulblets drop into the soil beside their 

 parents, ready to form new plants. It is interesting to 

 know that the first fronds from these bulblets are much 



