XLiii] . MATTEUCCIA i55 



caj>e/ise (Fig. 701,22): compare also Mettenius (7^//. Hort. Lips. PI. IV, Fig. 21). 

 Each vein is continued a short distance beyond the sorus, but it stops where 

 the margin of the pinna curves over as a continuous protective flap. This 

 resembles an indusium, but it is firm in texture, and is coloured brown. In 

 addition to this protection each sorus of M. orientalis is covered by a shell- 

 shaped indusium, attached on the side next to the mid-rib (Fig. 678, L). It 

 is structurally like one of the ramenta or scales. A section through a sorus 

 shows how the leaf-margin overlaps this scale, giving a very complete pro- 

 tection to the sori within (Fig. 678, E). The receptacle is convex, and a short 

 tracheidal branch enters it. The numerous sporangia are arranged in basi- 

 petal succession, a fact already demonstrated develop- 

 mentally for Onoclea sensibilis (Fig. 681). In fact we 

 are here dealing with a typically gradate type of 

 Ferns, which has both a protective leaf-margin and a 

 basal indusium. 



The development of the sporangia of the Ostrich 

 Fern has been described in detail by Campbell {Mem. 

 Bost. Soc. Nat. Hist. IV, 1887). Their orientation is not 

 exactly maintained in the mature sorus, though it is 

 indicated in their early development. This fact is 

 related to the structure of the sporangial head, which 

 is still unequally convex on its two sides, as it com- Fig. 681. Onocka sensibilis 

 monly i.s in gradate Ferns: but the annulus is nearly ^„,S:"fhSV"b:"p«:l 

 vertical, and the series of cells is definitely interrupted succession of the sporangia. 



- , ,, /7-,7 -7 -7- o /= indusium. ( x 200.) 



at the msertion of the stalk (Phil. Trans. 1899. 



Vol. 192, p. 56, PI. 5, Fig. 91). In fact the annulus is of the type character- 

 istic of advanced Leptosporangiate Ferns, though the sorus is like that of 

 the Cyatheaceae. These details will be found to be important for comparison 

 with M. intermedia. The spores are large, and their number in each 

 sporangium is between 48 and 64. The occurrence of a perispore is incon- 

 stant in the Onocleoid Ferns (Hannig, I.e. p. 340). It appears to be absent 

 in Ojioclea sensibilis: but Hannig found it present in MatteiLccia struthio- 

 pteris and orientalis. 



From the time of VVilldenow and other early writers a relation has been 

 recognised between the Onocleoid Ferns and Blechniim. There is a general 

 similarity of habit, but an obvious objection would seem to be the presence 

 of a true indusium in the former, and its absence in the latter. If then a non- 

 indusiate member of the Onocleineae were found, that would materially 

 strengthen an otherwise valid comparison instituted by the instinct of the 

 older systematists. The new species Mattenccia intermedia C. Chr. (Fig. 682) 

 proves to be non-indusiate (Christensen, Dot. Gaz. Vol. 56, 1913, p. 337). This 

 Fern is intermediate in habit between M. orientalis and M. strutJiiopteris. 



