Botany. 165 



ating this novel theory, although inaccurate in some minor 

 details, is of much interest, since it shows the intimate connection, 

 existing between the bast of the leaves and the anomalous bast 

 of the mature stem; but it by no means solves the question 

 whether the bast of the pith is developed from the original pro- 

 cambium, or by the metamorphosis of some of the medullary 

 cells. Very similar in this respect is R. Gerard's article* on the 

 changes of the tissues at the junction of the root and stern, 

 in which he discusses several plants with internal bast, and finds 

 that small bundles of sieve-tubes connect the anomalous and 

 normal bast just where the root passes into the stem. 



In the work before us Professor Lamounette confirms in the 

 main the results of Herail, but goes one step further, since he 

 :finds that even among the Cucurbitacece the internal bast clearly 

 develops later than the external. Not only is this the case at 

 the apex of the stem, and in the formation of the leaf-trace 

 bundles, but also in the first appearance of the anomalous tissue 

 in the hypocotyledonary axis. From this it appears that the so- 

 called bicollateral bundles of the Cucurbitacece are no more 

 uniform in their development than similar structures in other 

 groups, and de Bary's name for them is no more applicable here 

 than elsewhere. This is but one of the results contained in 

 Professor Lamounette's article, since he has extended his re- 

 searches to a large number of orders and has devoted special 

 attention to the very early stages in the development of the 

 tissue in question. His observations lead him to place the limit 

 of the tissues derived from the procambium, just within the in- 

 nermost of the primitive tracheal elements, which would show 

 that the anomalous bast must arise from the division and special- 

 ized development of cells which belong morphologically to the 

 pith. This having been settled, it still remains important to 

 ascertain whether the anomalous tissue stands in a primitive 

 connection with the normally oriented bast i. e. whether it is, so 

 to speak, merely a branch of the outer phloem system. Consid- 

 ering the nature of sieve-tubes as conductive tissue, this would 

 a priori appear highly probable. Professor Lamounette, how- 

 ever, has made the surprising discovery that the internal bast, at 

 the time of its first appearance, is entirely separate from the 

 normal system. This certainly seems opposed to the views of 

 Gerard, but the difference in results is probably due to the fact 

 that the latter observer examined somewhat later stages in che 

 development, where a connection between the outer and inner 

 bast had already been formed. In the mature plant there 

 -can, of course, be no doubt that these tissues stand in more or 

 less intimate communication, a fact demonstrated in very differ- 

 ent ways by Fischer, Weiss, Gerard, and others. While Pro- 

 fessor Lamounette's results are without doubt accurate for the 

 plants investigated by him, there is certainly one instance in 



* Ann. des sci. nat., 6th series, vol. xi, 1881. 



