Morphologie, Teratologie, Befruchtung, Cytologie. 403 



trace. The author points out that a similar elaboration of the abaxial 

 part of the bündle of the rachis, correlated with an increase in size 

 of the leaves or pinnae can be traced in certain species of Polypo- 

 dium from the Colombian Andes described in 1914 by Bor- 

 kowski. Dr. Davie shows that in the specimens of Polypodium 

 vulgare from Scotland, the leaves of which varied from 2 to 18 

 inches in length, abaxial development of the tracheides occurred 

 with increasing length of the leaf, though no separate abaxial 

 System was developed. 



The pinna-traces of Aspidium martinicense and A. trifoliatum 

 are given off marginally; in the larger-leaved examples of the for- 

 mer species a Strand departs from the abaxial System into the pinna; 

 in A. trifoliatum only traces of this abaxial contribution to the 

 vascular System of the pinna are found and in the shorter leaves 

 of A. martinicense no Strand is given off into the pinna by the 

 abaxial System. In Polystichum adiantiforme and Dryopteris grandis 

 the pinna-supply is of the extra- marginal type and is reinforced by 

 the addition of a Strand from the abaxial System (except in the 

 case of the terminal pinnae of the former species). 



Thus the relative development of the abaxial vascular System 

 of the leaf seems to be directly related to the length of the latter; 

 in the larger-leaved forms the abaxial System is no longer used 

 merely to reinforce the adaxial one, but contributes directly to the 

 vascular supply of the pinna. Nevertheless, in Leptochilus guianen- 

 sis, which has relatively small leaves, part of the pinna-trace arises 

 from the abaxial Strands of the rachis. This species is, however, 

 related closely to larger leaved species in which we should look 

 for a „contribution" type of pinna-trace. Then, again, among the 

 Cyatheaceae, in which long leaves and large pinnae are the rule, 

 we usually find an extra-marginal origin of the pinna-trace, com- 

 bined with an abaxial reinforcement. But the author has shown in 

 a previous paper that in Balantium culcita (L'Herit.) Klf. there is no 

 abaxial contribution to the pinna trace, the departure of which is of 

 a modified marginal type. On the other hand the combination type 

 of pinna-trace is found in Hisliopteris incisa (Thbg.) J.Sm., Pteris 

 (Litobrachia) macilenta A. Rieh., Lonchitis pubescens Willd. and Hypo- 

 lepis tenuifolia (Forst.) Bernh. It is suggested that in these species and 

 in Leptochilus guianensis the „combination" trace has been retained 

 owing to hereditary influence and that while the last-mentioned 

 plant was probably derived from larger-leaved species of the genus 

 the others may have originated from larger-leaved Cyatheaceous 

 types. 



Thus the form of the foliar bündle in the Ferns seems to be 

 dependent upon systematic position (sie), the length of the leaf and 

 the size of its pinnae. 



Among the Cycads the author deals with the strueture of the 

 foliar bündle in Stangeria paradoxa T. Moore, Zamia Lindem 

 Regel, Macrosamia Dennisonii F. Muell., Ceratosamia Kuesteriana 

 Regel, Dioon spinulosum Dyer, Encephalartos Altensteinii Lehm, and 

 Bowenia speetabilis Hook. In the first five species the pinna-trace 

 originates marginally. Though the abaxial System shows complica- 

 tions correlated with the length of the leaf no trace departs from it 

 into the pinna; it merely acts as a reinforcement to the adaxial 

 System. In Stangeria paradoxa the vascular System at the base of 

 the petiole has a closed outline, but it opens adaxially before the 

 emission of the traces for the first pair of pinnae. In Encephalartos 



