A Comparative List of Fern Pinna-traces, with some 
Notes on the Leaf-trace in the Ferns. 
BY 
R. C. DAVIE, M.A., D.Sc., 
Lecturer in Botany in the University of Edinburgh. 
With five Figures in the Text. 
I N three papers dealing with the anatomy of Fern-leaves 1 the contrast 
between the ‘ marginal ’ and £ extra-marginal ’ types of pinna-supply from 
the vascular system of the rachis has been emphasized. The contrast is not 
perfectly sharp and well defined—in one or two Ferns it is difficult to decide 
whether the type of pinna-supply is marginal or extra-marginal, for some 
forms of the extra-marginal type come very close to the marginal. But on 
the whole it can be said that the same type appears in the species of 
a genus; that the marginal type is found among the more primitive Ferns 
in the evolutionary scale and among the most advanced genera; that the 
extra-marginal type occurs in those Ferns which stand midway in the system 
of classification and in some advanced forms. 
Since the list summarizing the results of investigation up to 1914 2 was 
published, many Fern-leaves have been examined. The accompanying 
table shows the full number of species and includes those already mentioned. 
Every available genus containing members with pinnate leaves has been 
investigated. For several critical genera additional species have been 
studied. The list summarizes the result of the examination of 90 genera 
and mo species of Ferns. Fifty-one genera with 126 species have the 
marginal type of pinna-supply ; 46 genera with 94 species have the extra¬ 
marginal type. The overlap in the numbers of genera is due to the 
occurrence of both types of pinna-supply in certain genera, viz. Balantium , 
Leptochilus, Microlepia, Odoatosoria> Coniogramme , Notholaena , and 
Onychium . 
The width of the field which I have been able to cover is due to the 
kindness of the Regius Keeper of the Royal Botanic Garden, Edinburgh, 
1 The Structure and Affinities of Peranema and Diaealpe, Ann. of Bot., vol. xxvi, pp. 245-68 ; 
The Pinna-trace in the Ferns, Trans. Roy. Soc. Edin., vol. 1, pp. 349-78; On the Leaf-trace in 
some Pinnate Leaves, ibid., vol. lii, pp. 1-36. 
2 Trans. Roy. Soc. Edin., vol. 1, pp. 349-78. 
[Annals of Botany, Vol. XXXII. No. CXXVI. April, 1918.] 
