THREE SPECIAL CASES OF FERN HYBRIDS 



This was somewhat unexpected, and the problem of the other parent is immediately 

 raised. As far as the British flora is concerned there is here little choice, since the only 

 other species is P. angulare (Kitaib.) Presl {P. setiferum (Forsk.) Woynar*), which, as 

 already explained (cf. p. go), was for many years regarded as co-specific with P. aculeatum 

 and which certainly resembles it more closely in the adult state than does P. Lonchitis. 



Fig. 158. Meiosis In Po/yj^zVAwm tV/yncwm Hahne, permanent acetocarmine. x 1000. a. Diakinesis with 

 approximately 41 pairs and 41 univalents. For explanatory diagram see Fig. 159. b. First meiotic 

 metaphase showing total number of approximately 82 bodies. 



5^a ^. 



0^ oo 







P illi/r/cum n = 4/ 



Fig. 159. Explanatory diagram to Fig. 158 a. x 1500. Pairs in black, univalents in outline. 



To test this idea the attempt was made to hybridize P. aculeatum with P. angulare. 

 hs, parental stocks P. aculeatum from north Italy was used as a source of archegonia and 

 P. angulare from Dartmouth as a source of sperm. The hybrid (Fig. 160) proved easy to 



* According to the International Rules the valid name for this species is P. setiferum. The retention 

 of the older name of P. angulare for the purposes of this chapter is merely a temporary expedient to main- 

 tain consistency with the scheme of nomenclature indicated in the Preface. 



