VARIETIKS OF FERNS IN THE BRISTOL T>TSTRTCT. 225 



or loss dwarf, thoy aro both diatinot and pretty. The lax 

 and flexuose forms are just the opposite to the precedin"-- 

 the lobes, instead of overlapping, are far apart, with a dis- 

 tinct tendency in the frond to assume a weeping habit; the 

 extreme forms of floxuosum being absurdly twisted into 

 knots. In this class are included also those varieties in 

 which either the pinnules or piniur are refloxed. 



The Deltoid or Bi-achiate class includes (1) the forms in 

 which the frond broadens abnormally but symmetrically 

 towards the base ; and (2) those forms which are trinerved. 



The Cruciate class is perhaps the most remarkable of all. 

 In the most characteristic varieties of this class the develop- 

 ment of the pinniE is arrested in a very complete manner 

 at the basal h)l)os or pinnules, and the whoh"! strength of 

 what should have been the pinnas being thus thrown into 

 them, they develop to an extent sometimes truly mar- 

 vel knis, assuming almost the proportion and character of 

 pinnEB, and crossing, present the appearance which has sug- 

 gested the name. In the variety Athyrium. f.-f. Victoria! 

 the cruciate character is shown even in the minutest divi- 

 sions. There is a subdivision of tliis class in which tlio 

 development of the pinnae is not arrested, the piimulos 

 only assuming a cruciate character, while retaining their 

 natural sine. 



The Interrupted class is perhaps the one most generally 

 distributed, and in some of the species, and notably in Poly- 

 stichum angulare, it is so varied in its extravagances as to re- 

 quire very complicated classification. It includes, as its name 

 sufficiently indicates, all the varieties which are deficient in 

 any respect, — by thq partial or total arrest of the growtji of 

 the frond, pinna or ]Hinudo. The chief characteristic of this 

 class generally is ugliness, but there are many exceptions 

 in which the deficiency is so symmetrically diffused, that tho 



