WHITE] NOTES ON CHARACTERISTIC SPECIES. 873 



the bases, all tlu> ])innul('s showintr at an early stage a marked ten- 

 dency to division in two to live obtuse, rounded lobes, which, appear- 

 ing- at lirst as one or two rounded teeth a little above the middle, are 

 gradually cut one-half way to the rachis, sometimes, especially in the 

 somewhat heteromorphous basal pinnules, appearing slighly obovate 

 as the pinnule ])ecomes pinnatifid in its development into a pinna, 

 though generally the ovate or ovate-rhomboidal form, with confluent 

 or hardly constricted bases, is preserved to an advanced stage; lam- 

 ina of the pinnules not thick, very slightly depressed over the pri- 

 mary nerve in the pinnatitid pinnules, very faintly rugose, especially 

 on the dorsal, minutely striated, surface, and rolled rather strongly 

 backward at the margins so as frequently to make the pinnules or 

 lobes appear more acute thati they really are. 



Nervation of moderate strength, distinct and very slightly depressed 

 on the ventral surface, very close and in relief on the dorsal surface of 

 the pinnule: primary nerve originating at a nai"row angle, nearl}^ 

 opposite the proximal basal sinus of the pinnule, forking at an open 

 angle near its point of origin, and curving strongly outward in the 

 base of the pinnule, then forking pinnately and a little widely to sup- 

 ply a secondary nerA^e for each lobe, the secondary nerves forking 

 one to four times, at a moderate angle, in passing, a little distant, in 

 a gentle, slight curve to the distal border. 



The relation of this graceful and beautiful fern to the genus 2£arloj)- 

 ter'ix appears to be shown by the developmetit of the frond as well as 

 by the general details of the pinnte. Nevertheless, the aspect of the 

 pinnatifid portions of the frond, particularly when seen in small frag- 

 ments, showing the spreading, lobed, relatively unconstricted.' extended 

 pinnules, such as that shown in PL CLXXXIX, Fig. 8, as well as the 

 nervation, is often so similar to the corresponding parts in some of the 

 smaller, more compact forms of Erc'inopterh as to call in question its 

 generic attitude to the latter. The examination of a large series of speci- 

 mens shows the species in hand to be, however, one of easily recognized 

 in(li^'iduality. The very large size of the plant is evidenced by 

 portions of its rachis over 3 cm. in diameter, fragments of rachis, 

 apparently representing one of the larger of the four divisions of the 

 frond, being al)out 1.5 cm. in diameter when compressed. The rachises 

 of th(» lateral pinme are more slender than in most species of this 

 genus, and are slightly flexuose, in correspondence with the pinnation, 

 even where the axes have attained considerable development. 



The salient features Avhich are to be observed at the first glance at 

 small fragments of the fern ai-e a relatively close pinnation, with a 

 tendency to curve upward in the smaller j)irma% the closeness or 

 connatcMiess of the obtuse pimudes, and the marked tendency to loba- 

 tion. which shows even in the small and half-developed pinnules, the 

 lobes ap])earing as one or two or three inconspicuous shoulders, or 



