of the Anatomy of the Genus Selaginella , Spr. 143 
figure being in that respect more accurate than his text. In 
the structure of the stele he distinguishes, although he does 
not figure, protophloem and metaphloem, protoxylem and 
metaxylem. He describes the metaphloem as 4 generally ’ 
consisting of two layers, one of which consists of fascicular 
parenchyma next the wood, the other of sieve-tubes with 
larger lumina. The modification ‘ generally 5 requires expla- 
nation ; if it means that there is ‘ generally ’ one layer (one or 
more cells deep) of parenchyma next the wood, and a layer 
(in the same sense) of sieve-tubes without, then the statement 
might have been made absolute, for that is the arrange- 
ment in all the species ; if, on the other hand, 4 layer ’ means 
a single layer of cells, then the term ‘generally 3 is inaccurate, 
for very few species have their metaphloem so much reduced. 
No help is to be obtained from his figures, which frequently 
represent steles with far fewer layers in the phloem than 
they really possess. In none of his figures does Dangeard 
distinguish between parenchyma and sieve-tubes, nor does he 
state whether his sections are taken from young or from old 
stems, or from the creeping or from the erect portions of the 
axis. The limiting layers of the vascular cylinder are usually 
known as the pericycle, but Dangeard, although . accepting 
the conclusions arrived at by Vladescu with regard to the 
origin of these layers, goes further, and remarks, ‘ II nous 
parait difficile de separer cette assise du liber avec lequel elle 
se confond parfois, et, en attendant le travail definitif de 
M. Vladescu, nous la rattacherons au liber sous le nom de 
periphragme.’ I am quite unable to follow him in this ; 
indeed, the so-called pericycle is, in my experience, the 
easiest layer to determine in the whole anatomy. The fact 
that its cells contain chlorophyll is alone sufficient to enable 
one to clearly differentiate pericycle and phloem. Moreover, 
Vladescu’s observations, which are accepted and confirmed by 
Strasburger (24), demonstrate a quite distinct origin for the 
phloem. Dangeard, finally, proceeds to tabulate the species 
according to the number and arrangement of the steles; to 
this part of his work I shall refer in my general summary. 
