:.0. 



A bi'cuicii 0- . iie axial Inindie oi' tiit* peoioiu is f;iven off 

 to each piiina, Lincl oacli oi' olieso, branclioG in the pinna 

 to foiTi tilt; anastomosinr; voins characteristic oi' the 

 leaves oi" I.larsiiia. The detailed development of tlie buii- 

 dles of t'he pinna v/as not studied, and it is not certain 

 whether they orir;inate as Sadebeck ('74) has shovm them to 

 in Asplenirjn. The epidermal cells of the leaf give rice 

 to stomata on the upper side, or on both upper and under 

 sides, and lo deciduous trichomes like those of the pet - 

 iole. 



In the leaf of Pilularia. v/hich v/as examined for 

 comparison with T'larsilia, the segments of the two sided 

 apical cell foi-m but three sections, and leave tlius es> 

 ultimate mar£;inal cell of Uie fourth, grade. The sections 

 correspond in relative position to the first three in Mar- 

 silia, but they ajid the ultimate marginal cell are broder 

 than in the latter, sinde the wliole semicircular sognent 

 is here made up of tiic fouj." divisions, instead of contain- 

 ing si;: divisions as in ffersilia. Here as ir: Marsilia 

 the outer part of section I is split by a pericline into 

 two Culls, each of wliich plays tlie same role as one oi' 

 the other v/hole sections, in the develop ent of tlie periblrm 

 and dermatogen structm-es. The marginal cell, as well as all 

 of the sections, h.ere takes part in formin^^ the axial b nn- 

 dle, and as will be seen from the number of sections, tliere 



