2 
DR R. C. DAVIE ON 
paper recently published (Borkowski, ’14) gives a description of the anatomy of the 
leaves of Colombian species of Polypodium grown in sharply contrasted natural 
surroundings, and has afforded the opportunity to extend the comparisons made 
among the Brazilian species. Plants of Polypodium vulgare, Linn., have also been 
collected in Scotland, at ^ea-level and at varying altitudes up to nearly 3000 feet 
above the sea, from rock-clefts, wall-tops, hedge-bottoms, stream-sides, and tree- 
trunks. And the comparisons made of the species of Ferjis have been amplified and 
corrected by an examination of leaves of Cycads, Palms, and other Monocotyledons, 
and selected forms of Dicotyledons. 
From the results of these investigations, which have been confined to pinnate 
leaves, but which have been spread over as wide a systematic field as possible, and 
which include a detailed examination of many forms of a single genus and of several 
types of a single species, it has been possible to draw conclusions regarding the 
factors which control the branching of the vascular system of the leaf in various 
groups of plants. I have throughout attempted to read results in relation rather 
to the physiological needs of the leaf than to its inherited tendencies. And such 
ppinions as have been stated on questions of phylogeny have been printed only after 
the evidence seemed overwhelmingly in their favour. Vascular anatomy must at the 
best take a subsidiary place among the criteria which are valuable in the work of 
classifying plants. But the extraordinary parallelism which has been established for 
the Ferns between my results and the conclusions reached by the distinguished 
author of the Index Filicum has made worth mentioning a sphere in which anatomical 
characteristics may be usefully employed in confirmatory work. 
I desire to acknowledge the assistance of a Government Grant,* which enabled 
me to visit Bio de Janeiro and Sao Paulo and to collect material in the vicinity 
of these cities. 
Whilst in Rio de Janeiro I was given every facility to prepare my collections and 
to consult literature by Dr J. C. Willis, then Director of the Jardim Botanico, to 
whom I express my thanks. 
I desire also to express my thanks to the Regius Keeper of the Royal Botanic 
Garden, Edinburgh, who supplied from the Garden collections much of the material 
described below; and to Professor F. 0 . Bower, F.R.S., who during the progress of 
the investigation made criticisms and suggestions which materially altered its scheme 
of construction and widened its field of inquiry. 
The Brazilian Species of Polypodium. 
Ten species of Polypodium were collected in natural situations in Brazil. One of 
these, P. brasiliense, Poir., was found on three separate occasions, under different 
natural conditions. It was found in the undergrowth of the rain-forest on the slopes 
of Monte Corcovado, which rises behind the city of Rio de Janeiro. Between the 
* Placed at my disposal by the Royal Society. 
