A NEW JAPANESE POLYPODIUM. (37) 



the lobe, and in greater number towards its apical portion, where there are 

 about 36 in a square mm. They are of ordinary structure and form, and about 

 0.054 mm. long and 0.045 mm. broad The cross-section of the lobe shows 

 a layer of subquadrate epidermal cells with moderately thin cuticle, mesophyll 

 of stellate cells, and a single vascular bundle. The naked sorus occupies the 

 whole breadth of the lobe at its base, and consists of numerous sporangia 

 mixed with ordinary hairs of the frond. The sporangia are long-stalked and 

 much bulged out on the side opposite to the annulus; their diameter is about 

 0.2 mm. The number of segments of the incomplete annulus is about 20. 

 The spores are spherical, green, minutely granular on the surface, and about 

 0.046 mm. in diameter. They germinate soon often sowing. It is not uncom- 

 mon to find spores divided into two hemispheres by a wall. 



This is a very small species of Polyp odium, of which I do not find any 

 description either in books and articles on plants of Japan and adjacent coun- 

 tries, or in works on ferns in general and of particular regions. It may be 

 placed near P. andinum, Hooker, P. subpinnatifidMin, Hooker, P, organense, 

 Hooker, P. trickomanoides, Swartz, and the like. But from all these larger 

 species it differs in various respects, and especially in its veins being simple in- 

 stead of forked. 



Plate XXI. Fig. i, large specimen of the plant (nat. size); 2, frond (x 

 3); 3» portion of frond showing the sori (x 5); 4, sporangium ( x88); 5, spore 

 ( X 240); 6, spore divided into two hemispheres by a wall ( X 240); 7, hair of 

 frond (x 88); 8, scale at the base of stipe ( x 53); 9, minute hair on the under 

 surface of lobe ( x88); 10, vertical section of fertile lobe ( X 26), a termination 



