PLANTS FKOM ALASKA. If)!* 



to have hoon a raised conl-like line, runiiiiip; down tlie centei- of tli(>ir 

 uppei' sui'faco. The ])i'iniai'v i)inn;r of this speciincii go off fi'oiii lli(> 

 main I'achis op])osile to one another. I'h .\L. I'i<i'. 2. shows two of the 

 pinnules enlai'ijed. Another speciincai, which is g-ixcn in I'l. \\j. l-'iii. 'A. 

 seems to helonj; to a position nearcM' t li(> end of the comijound pinn;i t h;in 

 the part I'epresented in Vig.. I. 1( is also a poi't ion of an ante|)(MUihimate 

 ])inna. In this the ultimate pimue aiv nuich I'educed in size, and the 

 .same is ti'ue of the pinnules; 'rii(> latter are more united and lend to 

 pass to lobes and teeth. Many of tlu^ pimiules and lobes in this foi'in 

 are much nuitihiled and do not show tlieii' time sha|)e. 1*1. .\L, ]''if>;. 4, 

 shows the lower part of a piniuile enliiixcd. 'The foi'm fiiven in PI. XL, 

 Fig. 5, probably i'e{)resents a stage between these two. ThLs gives one 

 of the ]ien\iltimate pimue more complete. PI. XL, Fig. (), shows a jiinnule 

 enlarged. PI. XXXIX, Fig. 9, probably represents a ])oi-tion of a penul- 

 timate pinmi from lower down on the compound piiuia than any of 

 those shown in PI. XL, Fig. 1. Tn this the pinnules aic inoi'e separated 

 than in any of the other spe<'imens. They ai'e also larger, and the largest 

 of them show serrate teeth. These can be seen distinctly only with the 

 help of a lens. They ai'e shown in the magnified pinnule, PI. XXXIX, 

 Figs. 10 antl 11. It is probable that still lower down the teeth become 

 more pronounced and take the character shown in ('lodophlebis oJota. 



This plant seems to l)e identical with two fei'iis first found in (he 

 Potomac, or Lower Ci'etaceous foi'mation. They are (IdduphUhi^ (ilata 

 and Pecoptcris stricti7tcrvis. These specimens make it most probable 

 that the two ferns from the lower Potomac of Virginia, called by the 

 present writer Cladopklebis alata and Pecoptcris sirictincrvis. nre the 

 same. Pecopteris stricfinenHs represents upper and terminal portions 

 of the fi'ond and compound pimue. ('hiilojililvliis (ihila is the foi'ui found 

 lower down. The larger pinmiles of the fossil represented in PI. XXXIX, 

 Fig. 9, are forms establishing a passage from the nlata to the stnclinervis 

 type. Most of the specimens belong to the stnclinervis type, and none 

 with dentation so pronounced as that in ('.dhila were found. Some of 

 the pinnules of Pecopteris sirictinervis, as seen in the \'irginia Potomac, 

 show a toothing similar to that found in the foi'ui depicted in l"ig. .'1 

 The following description of the fo.ssil nuiy be given: 



The plant was prol)ably arl)orescent with strong rachi.ses aiul wide 

 spread of foliage. Tlu^ epidermis seems to have been firm .and dui-able, 



