jig 



Lave been noted also in other genera, so that A;//</<w docs not stand 

 ,loiu\ though ihe demonstration is most effective ill that genus. 



In putting a morphological interpretation on these lads it is to be 

 cmcmbcrcd that the genus A///,/,,/ has in many of its specie's vei \ 

 long sori compared with those of .!/<;/v///</. Kxiernal comparison had 

 \ suggested an elongation of the type of the latter genus to produce' 

 a sorua of Aw/<w. The internal structure is now seen to be conform- 

 le to such a progression, tor the partial scptations are commonly 

 found in those sporangia which are larger than the normal: they thus 

 appear to have followed upon expansion of the sporangia. Their existence 



Parl -I .1 fi.'ii'l wiili tli- M.iitix. Reduced after a 

 piioi,.-iapii hv MI. \\ . ii. mini army, From So i A'O.VA// AW<iy. 



here, as well as occasionally in other genera, raises the question whether 

 or not septation has been effective in the primary production of the 

 sorus: this will he considered again laler. 



The synangial sori differ from those with separate sporangia in the 

 mechanism which accompanies dehiscence, though the dchiscence itself is 

 uniformly 1>\ a radial slit. The annulus represented in . ///.v/','/>/Vm by a 

 hroad indurated hand or hoop, is absent: clearly it would be useless in 

 a sxnangium, for it could not possibly be effective unless the sporangium 

 were free from mutual relations with others. In KavlfuSSia and Dannca 

 the radial slit of each sporangium may widen as the neighbouring cells 

 drv up, to form an almost circular pore. In Af,trnffin there is in addition 

 to this a change of lorm of the whole sorus at maturity: its two sides, 

 originally in dose juxtaposition so that the distal ends of thcii sporangia 

 almost touched, move apart like the opening of a hook. In /)ti/itn' t i 

 and Mtirnttiii the whole external wall of the synangium is composed of 

 deep indurated cells: the condition of Angwptcri* appears accordingly 



