532 Boodle . — Comparative Anatomy of the 
mentioned (Boodle, ’01, p. 376). .S'. dichotoma was found 
to behave in a similar way. A transverse section of the 
rhizome was placed in strong sulphuric acid, with a section of 
Cncurbita as a control. Some time after the greater part 
of the cellular tissue in the control had swelled up and dis- 
appeared, a very different result was seen in the section 
of Schizaea. The walls of the tracheides were considerably 
swelled, but sharply outlined walls remained representing 
practically all the rest of the cells. Previous boiling of the 
material in water did not alter the effect of the acid. 
The differentiation of the xylem, as seen in a microtome- 
series of sections of the stem-apex of S', dichotoma , is irregular. 
Thus, taking one particular part of the stele as an example, 
no tracheides were differentiated except one at the extreme 
outside and one at the extreme inside of the young xylem- 
ring, while, in other parts of the ring of xylem, tracheides 
in an intermediate position may be the first to differentiate. 
The differentiation may also be much further advanced on 
one side of the stele than on the other, in relation to the 
nearest leaf-trace. 
The sieve-tubes of S', dichotoma appear to be of a fairly 
normal Fern-type. 
The petiolar bundle of S. dichotoma is of a similar type 
to that of S. elegans figured by Prantl (’ 81 , Taf. IV, Fig. 40). 
Fibres are present in the usual position, and protoxylem 
appears to lie at two points on the upper side. In the leaf 
the stomata are placed in two neat longitudinal rows, just 
as in S. pusilla (Britton and Taylor, ’ 01 , p. 14). In the 
flattened part of the leaf the bundle is similar to that of 
the petiole, the epidermal cells are very thick-walled, and 
the stomata are raised. 
Recent Works treating of the Morphology of 
Tissues. 
Reference should now be made to certain views regarding 
the stele and the morphology of tissues, which have been 
recently published. Farmer and Hill (’ 02 , pp. 396 and 400) 
