6 AEÏ. 12. — K. YENDO. 



section are mostly linear, but subterete in some species ; in this 

 respect gradually approaching the preceding section. Amp. 7iodu- 

 losa has nearly cylindrical articuli, slightly compressed in the 

 ultimate articuli. Amp. canaliculata Mart, has essentially broad 

 and ancipitous articuli at the upper portions of the fronds. Both 

 margins, however, are inflexed very much to one side forming a 

 pair of canals along the margins. This is found to be the case 

 in some other species, though in a slight degree, such as Amp. 

 foliacea and Amp. misakie7isis. 



Some of the members, such as Amp. BovjerhankU, Amp. 

 anceps, Amp. canaliculata Mart,, Amp. foliacea, etc., are habit- 

 ually decumbent. This causes the differentiation of dorsiventrality 

 in the upper articuli. The canaliculatad species have the canals 

 at the ventral side only, or in other words, on the shaded side : 

 and the conceptacles are to be found on the dorsal side only. In 

 the uncanaliculated and decumbent members the conceptacles are 

 restricted to the shaded surface with a few conceptacles occasionally 

 found on the opposite side. In the erect forms they are found 

 on both surfaces. 



The decumbent habit may have been caused by the fact that 

 the genicula of the basal portion in these species develope further 

 and finally form large horny flexible joints. These joints, i. e., 

 the bandform genicula, allow the ujoper portions of the fronds to 

 bend downwards. In the preceding section the lower genicula 

 are very short and form the constrictions of the moniliforni stems 

 at the basal portions of the fronds. The short linear genicula 

 cause the fronds to stand upright. 



Amp. anceps Done., according to Harvey's description and 

 illustrations,^^ is identical with Amp. dilatata Aresch. Areschoug 



1) Ker. Austr. p. 'J8. t. 37. 



