108 * Pflanzenkrankheiten. — Pteridophyten. 



malades; en les coupant ils se forment des decolorations d'un rouge 

 intense. La coloration augmente avec la consistance molle des 

 tubercules. Dans les tropiques les enzymes agissent autrement qua 

 dans les pays temperes. La composition chimique des tubercules 

 est certainement differente. D'apres l'auteur leclimat tropicalfavorise 

 certainement la maladie; puls d'autres facteurs encore inconnues. 

 Comme traitement eile insiste sur des ameliorations rationnelles ä 

 faire dans les cultures de ces pJantes. — A Java la culture des 

 pommes de terres est une culture des indigenes, qui se fait d'une 

 maniere primitive. A. E. Cretier. 



Sampson, K., The Morphology of Phylloglossum Dvuntmonäii, 

 Kunze. (Ann. Bot. XXX. W 118. p. 315-33L 5 text tigs. April 1916.) 



The author has had her disposal two collections of Phylloglossum 

 Druninwndii, one of which contained fertile plants more than 

 usually well developed, some of them showing more than one new 

 tuber. At the base of the plant the root-steles unite to form the 

 main stele; this consists of anastomosing meristeles. Before the 

 formation of the new tuber the vascular System usually consists of 

 a meduUated stele; this divides unequally into U-shaped daughter 

 steles, the gaps in these facing one another. The smaller stele first 

 bends sharply upwards for a very short distance and then sharply 

 downwards entering the tuber. In these well-developed plants the 

 ieaf traces arise both from the main stele and from the stele of the 

 tuber, but in less vigorous plants no leaf-traces were associated with 

 the latter. In such forms, too, the xylem may be broken up into 

 several bundles in the main stele below the peduncles. Bertrand's 

 „Organe de Mettenius'' is nothing but a rudimentary Ieaf, associated 

 with the protocorm. 



The author argues that the tuber is abranch, highly specialised 

 for the storage of food. This view is supported by the connection 

 of some of the leaf-traces with the stele of the tuber, as well by the 

 fact that the smaller daughter-stele curves slightly upwards, a 

 course which is regarded as vestigial and showing a change of 

 direction in the growth of the axis. Both these characters are found 

 only in the more vigorous specimens; as Phylloglossum is clearly a 

 reduced form these are the specimens in which we should expect 

 primitive characters to be most clearly shown. It is further pointed 

 out that in the branching of the fertile forms a gap occurs similar 

 to that found in the larger daughter-stele after the vascular supply 

 of the new tuber has been given off. 



In the plants with more than one tuber the anatomy shows that 

 these tubers are to be regarded as due to a further process of 

 branching. When they arise on the same side of the. stele they 

 appear to be due to a dichotomy of the stele of the new tuber 

 itself; when the tubers arise on opposite sides of the main stock 

 they are produced by a repetition of the process of branching and 

 division of the main (or larger daughter-stele). In the latter case 

 the two tubers may appear to be produced at the same level, but 

 the anatomy shows they are always due to successive branchings. 

 Thus even the sterile plants of Phylloglossum. cannot be regarded 

 as unbranched, since each produces at least one branch, the new 

 storage-tuber. Further the tuber is not really comparable to the 

 protocorm of Lycopodium. Isabel M. F. Browne (London). 



