8o Gwynne- Vaughan. — Observations on the 
split up along a spiral line, the spiral band thus formed being 
several bars of thickening in breadth (Fig. 9). 
Attempts were made to obtain microtome sections of the 
stem-apex, but the material was not sufficiently well preserved 
to give good results, and the details of the apical development 
could not be followed. The termination of the stem is broad 
and flat, and from this the extreme apex arises rather abruptly 
as a small cone terminated by an apical cell. The soleno- 
stele was clearly delimited from the ground-tissue on both 
sides up to a point very near the apex, but I was unable to 
decide whether the lines of delimitation coincided with the 
first two tangential divisions in the apical segments, as stated 
for Ferns by Van Tieghem \ or not. One point, however, 
came out with sufficient clearness regarding the origin of the 
so-called pericycle, which certainly arises from centripetal 
divisions (i. e. towards the centre of the solenostele) in a layer 
of cells which also gives rise to the endodermis. This holds 
good for both the internal and the external pericycle. In 
Loxsoma , therefore, the phloeoterma is not coincident with 
the endodermis, but is to be found in the innermost layer of 
the pericycle bordering upon the phloem. 
The Root. 
The structure of the root is essentially that of a typical 
Fern. There is a slender diarch xylem-plate, the protoxylems 
of which abut directly on the pericycle, which is one, or in 
places two, layers thick. Protophloem and phloem are very 
distinct, and the latter is separated from the xylem by a layer 
of parenchyma. The endodermis is well marked, and similar 
to that in the stem. The cortex consists of four or five layers 
of cells which increase in size from the endodermis outwards ; 
their walls are somewhat thickened and coloured brown. The 
cells of the suberized layer are radially elongated with especi- 
ally thick walls ; they usually remain as the outer limit of 
the root, the piliferous layer being early destroyed. The 
1 Traite de Botanique (2nd ed.), p. 774. 
