THE MALE FERN DRTOPTERIS FILIX-MAS 



Hybrids between D. Filix-mas in the restricted sense and D. abbreviata were success- 

 fully produced in 1939 using spermatozoids of a D. abbreviata from Greenhill Dod near 

 Glasgow (Fig. 32 c) and archegonia of a D. Filix-mas irora Ingleborough, Yorkshire 

 (Fig. 320). Two hybrids were obtained out of six inseminations, the other four remain- 

 ing without offspring. The hybrids were attested as such by showing a chromosome 

 number intermediate between that of the two parent sporophytes {2n = c. 120), and 



Fig. 32. Comparable pinnae, natural size, of the triploid hybrid {b) between Dryopteris Filix-mas 

 sens. strict. emend, from Ingleborough {a) and D. abbreviata (Lam. & DC.) Newm. from Greenhill 

 Dod near Glasgow (c). 



meiosis has since been seen in both. The first sporangia were produced on one of the 

 plants in 1943, though, unfortunately, it died in the following winter; the other was 

 first fertile in 1944, and had become a large plant by 1948 when the silhouettes of 

 Figs. 326 and 33 were taken. In pressed condition it is so like D. Filix-mas that it 

 would probably be mistaken for that species but for its abortive spores and abundant 

 ramenta. It is, however, definitely intermediate between its two parents in most charac- 

 ters as Fig. 32 may perhaps suggest. The frond is slightly concave when viewed from 

 above, though less so than is D. abbreviata. The stock has, however, become much 



MFC 



49 



