190 THE MARATTIALES 



be seen, like those which are much more developed in the primary root of J ngiop- 

 teris, and it was also seen that certain of the cells in the cortex of the primary roots 

 were invaded by the endophytic fungus. In the cotyledon there was a single large 

 mucilage duct. 



A series of transverse sections was made of a young sporophyte of M. sam- 

 huctna and these agreed in all essential particulars with similar sections oi Danxa 

 or Kaulfussta. . 



In a young sporophyte of M. douglasii, in which two roots were developed m 

 addition to the primary one, there could be seen at the apex two young leaves, prob- 

 ably the fourth and fifth, but as only the median sections of this series had been 

 kept the exact number of leaves could not be determined. 



The central part of the stem in this plant (fig. 173) was occupied by a single 

 thick bundle, but whether this was solid or open on one side, as Farmer states is 



Fic. 174. 



A, B. Two longitudinal sections of an older sporophyte of Marattia douglasii. st, stem apex; m, mucilage ducts. X^S- 

 C. Stem apex. Xi8o. 



the case in M. fraxinea, could not be satisfactorily determined. At this stage the 

 section of the young plant almost exactly resembles a similar one in Damsa, and 

 presumably the single central strand is composed of the confluent leaf traces from 

 the three first leaves, as it is in Dancea. 



The xylem of the bundle is still composed exclusively of short, reticulate tra- 

 cheids. Large mucilage ducts and numerous tannin sacs are developed in the 

 petioles of the older leaves and the elongated tannin sacs, like those in the roots of 

 Dancea and Angiopteris, are sparingly developed in the young roots; but both tannin 

 sacs and mucilage ducts were absent from the stem tissues at this period. 



In a still older plant (fig. 174) the single central bundle of the basal region is 

 replaced by the separated steles of the single leaf traces, which are beginning to form 

 the open dictyostele characteristic of the adult sporophyte. The exact nature of its 

 origin could not be followed in the material at my disposal, but it is presumably 



