92 PP. REPORT OF PROGRESS. FONTAINE & WHITE. 



Sterile fronds, about 2f cms. wide, and 20 cms. long; leaf- 

 substance, ratlier thick and coriaceous, having a smooth, 

 shining, carbonaceous iilm; lateral nerves, very fine, closely 

 placed, and immersed in the parenchyma of the frond, 

 leaving the mid-rib at a right angle, or with a very slight 

 arch immediately at the insertion, mostly simple, but fre- 

 quently branching once at irregular distances from the 

 mid-rib, more rarely one or both of the branches again 

 branching, all in a peculiar dichotomous manner, so that 

 the nerves and branches continue parallel to each other to 

 the margin ; fertile frond, usually much smaller than the 

 sterile one, and narrower, entire near the base, cut into seg- 

 ments which extend about half way to the mid-rib in the 

 middle, and upper part of the frond; segments separated 

 by very acute angled sinuses, round to truncate at the ex- 

 tremit}^, void of nerves, and containing beneath the sinus 

 oval sori, which are apparently attached by their broad 

 base to a receptacle near the mid-rib; receptacle, elliptical, 

 flattened on one side, and leaving on each side of the mid- 

 rib a row of distinct impressions of the same shape.) 



The fertile frond contains two rows of broadly ovate sori, 

 which stand one on each side of the mid-rib, and are so 

 placed that the axis of each sorus stands perpendicular to 

 the mid-rib, and just under the sinus separating each pair 

 of segments. The sori extend just up to the bottom of 

 the sinus. The basal portion of the fertile frond is free 

 from segmentation and fructification, and possesses nerves 

 like the sterile frond. The segmented portion shows no 

 nerves. The segmentation of a frond often begins before 

 the appearance of the sori, as shown in the plant given in 

 Fig. 7. Fig. 2 gives the normal form of the fruiting frond. 

 Fig. 1 is the middle portion of a fertile frond. Fig. 3 shows 

 the plant with the impressions left by the insertions of the 

 base of the sori. 3a gives an enlarged representation of 

 the impressions, and Fig. la of the sori, with their bases 

 at the upper part of the figure. Neither the sterile nor the 

 fertile fronds have been seen entire. Figs. 4, 5, and 6 give 

 the base, middle jiortion, and end of the sterile frond. 



Macrotaeniopteris Rogersi, Schimp. of the Richmond 



