66 Palmer Ferm of the Dismal Swamp, 



it is stouter, more fleshy and grooved for only a short distance above the 

 lower pinna, or faintly further. 



In D. crist(il, Jlni-hiana and in clintoniana the basal pinnules of all 

 the pinnae are largest and longest; in celsa and goldieana, some pinna-, 

 especially the apical ones, are similar, but the lower piniue, especially the 

 lowermost, have the pinnules, even for several pairs, very much reduced. 

 In good fertile fronds of celxa and goldieana the lower basal pinnule of the 

 lowest pair of pimue is always absent but sometimes present or appar 

 ently present in some undersized fronds. This is often the case in gol 

 dieana, but only occurs rarely in cdsa. The basal pinnules of the upper 

 pinme of both these ferns are always opposite and very exactly so, but 

 they begin to diverge at the centers of the piniue. On the lower piniue 

 this p tiring is rare and it is not easy to determine whether the opposite 

 of the reduced upper basal pinnule has never been developed or whether 

 it is represented by the one occupying the adjoining position. This latter 

 view would seem to be correct, the lower pinnules having been gradually 

 moved along the rachis toward the tip during the evolution of the form. 

 In very young fronds (Figs. 5, 8) there is a wide space of the lower pinna 

 beneath, the pinnule seems forced away from the rachis and the base 

 of the mid vein, inclines toward the rachis of the pinna for some distance. 

 The same result is shown in numerous young fronds of both forms. Fig. 

 14 represents the common type of goldieana, while Figs. 6 and 9-12 are from 

 specimens of celsa. 



Dryopteris goldieana is extremely herbaceous and robust, its pinnules and 

 pinnae being large and often overlapping. In celsa they are always widely 

 separated ; both are much narrower, and there is no sudden change from 

 the long, wide pinnae to the shorter, narrower one of a crowded apex as 

 in goldieana. The reduction or absence of the lower pinnules results in 

 producing a stalk for the pinnae, short in goldieana, longer in celsa. 

 The pinnae of celsa incline upwards very decidedly, whereas in goldieana 

 they stand at a right angle to the rachis or are only slightly inclined up 

 wards. These differences between the very erect narrow celsa and the 

 broad, drooping and herbaceous goldieana result from differences in hab 

 itat, the dryer and lighter situation of cdsa contrasting in its results with 

 the gloomy, damp habitat of goldieana. 



On July 30, 1899, I found two clumps of goldieana on the Virginia bluffs 

 of the Potomac river opposite Cabin John Bridge. The first contained 

 over fifty plants, all with well drooping fronds and nearly all the lower pin 

 nules of the lower pinnae normal. These plants were growing at the 

 foot of the talus among the rocks, and the trees formed a dense canopy 

 overhead. In the second clump a mile further down, in a precisely sim 

 ilar situation, were several dozen plants. But here the thinness of the 

 foliage overhead permitted the sun to shine on the plants for several 

 hours daily. The early fronds were drooping as in the first clump, but 

 the later and mostly fertile fronds were more erect, and the divisions were 

 less herbaceous and consequently less crowded, but in no case to the same 

 extent as in celsa. 



