Embryo and of that of the Grass in particular. 513 
Coulter has recently given vigorous support to the same theory as 
that held by Bruns, viz. that the mesocotyl is the first internode of the 
epicotyl, thus bringing his view that the epiblast is a second cotyledon into 
line with the rest of the morphology. This article is an astonishing one for 
two reasons. Firstly, because his deductions are based, like those of Bruns, 
entirely on the outward appearance of the advanced embryo ; the mesocotyl 
looks like an internode succeeding two apparent cotyledons, therefore it must 
be an internode ! Secondly, the important developmental and anatomical 
facts disclosed by Hanstein, van Tieghem, and Schlickum are completely 
ignored ; the article by this last author and the very important one by 
Celakovsky are not cited, the entire treatment of the subject being thus 
one-sided. It seems to me a pity that the writings of these previous 
workers should have been over- 
looked, especially as the con- 
elusions involved are rather im- 
portant. 
Schlickum, as a result of 
his investigations, finds that the 
Grass - seedling essentially re- 
sembles in all its morphological 
parts that of other Monocotyle- 
dons, and a continuous series of 
transitional forms between the 
two can be instituted. He says 
that the coleoptile differs in no 
essential point from the cotyle- 
donary sheath of other Monocotyledons, such as Canna and Car ex. Just 
as in the case of other investigated Monocotyledons, there exists a great 
difference, e. g. in Oryza and Panicum , between the structure of the 
coleoptile and that of the first plumular leaf-sheath, whilst, on the other 
hand, the first and second plumular leaf- sheaths exhibit only trivial 
differences between themselves. He states further that ‘ as the rudiment of 
the coleoptile arises in the tissue complex which is becoming the scutellum, 
I must,* as does also Hegelmaier, agree with Hanstein, and like him, on the 
basis of developmental data, equate the scutellum with the haustorium and 
the coleoptile with the cotyledonary sheath of other Monocotyledons 
From what has been stated above there is obviously no foundation for 
Bruns’s and Coulter’s view that the mesocotyl is the first internode of the 
epicotyl and that the coleoptile is the first plumular leaf. The possession 
by the coleoptile of two widely-separated vascular strands which are situated 
much nearer to the two margins than they are to each other, strongly 
suggests a ligular structure formed by the union of stipules. If this organ 
represented an independent (first plumular) leaf this type of venation would 
Fig. 5. A. Panicum miliaceum. Transverse 
section of vascular system of mesocotyl. ph = phloem 
(diagrammatic), b. Oryza saliva. Ditto. scb = bundle 
destined for scutellum. (After Schlickum.) 
