(246) FERNS OF JAPAN. 



The creeping rhizome is 3 to 4 mm. in diameter, densely clothed with 

 somewhat subulate and slender-pointed, dark-brown scales, the largest of which 

 are about 3 mm. long. The roots are tomentose with dark-brown hairs. » The 

 transverse section of the rhizome shows oval vascular bundles, about eight in 

 number, arranged in the form of a circle. The stipes are slender, glossy, canalicu- 

 late in front, and stramineous when dry ; they are about i . 5 mm. in diameter, . 

 Their cross-section shows a large vascular bundle in the center and a small 

 one by its side; the large bundle has a group of scalariform vessels in the 

 center in the form of the letter T. The fronds are usually 20 or more cm. 

 long; but small ones are only about 10 cm. long and 5 cm. broad, with about 

 10 pairs of segments. There are minute jointed hairs on both surfaces of the 

 frond, and those on the upper surface have fewer but longer joints. The 

 segments of the frond are nearly of the same shape and mostly somewhat 

 curved upward, but the upper ones are gradually smaller and pass into the 

 taper-pointed terminal segment. The largest segments, which are below the 

 middle of the frond, are about 7 cm. long and 1.5 cm. broad, The lower 

 segments are separated from each other by a sinus 5 to 10 mm. wide, but the 

 upper ones are close together. The segments are all connected by the base 

 which widens into a wing on each side of the rachis. The free included veinlets, 

 on the apices of which the sori are produced, are formed by the branching 

 near the base and on the anterior side of the alternate veins proceeding from 

 the midvein of the segment. The sori are very regularly arranged and 2 to 4 

 mm. apart from each other; they are 1.5 to 2 mm. in diameter. The sporangia 

 have rather long pedicels; they are about 0,3 mm. in diameter; the number of 

 the segments of the incomplete annulus is about 10. The spores are subovoid 

 or subellipsoidal, almost transparent, minutely reticulate on the surface, and 



