478 Scientific Intelligence. 



III. Botany. 



1. Mecherches sur le developpement du tegument seminal et du 

 pericarpe des Gramin'ees ; by Paul Guerin. Paris, 1899. — 

 The structure of the pericarp and the seed-coat in the Graminece 

 is a subject that has not been studied very much hitherto, and it 

 seems as if most authors have confined themselves to the study 

 of those genera or species as are of purely economical value, the 

 Cereals for instance. The results of these studies are, however, 

 very diverse, so that we have not reached any definite conclu- 

 sion as to the real structure of the pericarp and seed-coat 

 before and after fecundation has taken place. Nevertheless the 

 Graminece have recently been classified under Van Tieghem's 

 " Inseminees" on account of some observations made by Jumelle, 

 who claims that both the external and internal integument of the 

 ovule in the Graminese become reabsorbed after fecundation ; thus 

 the fruit develops as an achsenium, enclosing a seed with no 

 seed-coat. This statement is very much in opposition to the 

 explanation given by Kudelka and Johannsen, who arrived at the 

 conclusion that only " the external " integument becomes reab- 

 sorbed, while the internal integument persists and grows together 

 with the pericarp. 



Not until a few years ago has the subject been taken up again 

 by Dr. Guerin, but this author has not confined himself to study- 

 ing Cereals alone, but has examined a number of representatives 

 of each of the thirteen tribes which are generally recognized as 

 constituting the order Graminese. The structure of the pericarp 

 and of the integuments of the ovule has been studied very care- 

 fully and compared with the final composition of the fruit and 

 seed-coat alter fecundation. Several very instructive illustra- 

 tions accompany the anatomical sketch, and show very plainly 

 the changes that take place in the ovary before and after the 

 fecundation of the ovule. But the results gained by Dr. Guerin's 

 painstaking studies are not in accordance with those presented 

 by Jumelle, thus there seems to be no foundation, so far, for 

 classifying the order among the "Inseminees." 



To do full justice to this important work of Dr. Guerin, it 

 would be necessary to give a detailed account of all the facts, as 

 presented, and we regret that the space assigned does not allow 

 more than a brief abstract of some of the results ; we must refer 

 to the paper itself for further details. The author confirms the 

 observations of Kudelka and Johannsen, that only the outer 

 integument becomes reabsorbed after fecundation has taken 

 place, and the formation of the seed-coat is, thus, solely due to 

 the persistence of the inner integument. The mature seed is 

 invariably surrounded by a seed-coat, even if the inner integu- 

 ment may, sometimes, become partly reabsorbed, but never com- 

 pletely so. The inner integument consists generally of one or 

 two layers of cells, and the innermost layer is, as a rule, the 



