of Vascular Strands in A ngiopteris evecta . 391 
should be regarded as the primitive type, the alternative form 
being, perhaps, confined to older ones. The general cortical 
parenchyma of the stem calls for no special mention, but It 
may be stated that the cells contain well-marked leucoplasts, 
and that their relation to starch formation can be very easily 
traced. 
Roots. It has already been stated that the primary 
root Is diarch. The first few lateral roots are somewhat 
variable In their structure, and often retain a diarch 
character. Then others appear which are triarch or tetrarch, 
and the latter are especially frequent. It is only by slow 
degrees that the more complex roots with their numerous 
rays of xylem and phloem put in an appearance. The roots 
arise, as has been already said, without any very definite 
relation to the leaves, a character which recalls the Ophio- 
glossaceae. They also vary considerably both in old and 
young plants as to their attachment. Sometimes they unite 
with the more central strands, though far more commonly 
with those peripherally situated. The striking relation ob- 
taining in Kaulfussia has already been described above. 
They originate in the very young region of the stem, before 
it is possible to distinguish clearly the nature of the tissue 
from which they spring, though in all probability it should be 
referred to the endodermis. There appears to be a single 
initial cell in the first instance, of a prismatic six-sided form, 
and segments are cut off parallel to the elongated sides, and 
also from the distal end, the latter giving rise to the root-cap. 
If transverse sections be examined which happen to pass 
through the root near its junction with the vascular tissue 
of the stem it will be often noticed that although as regards 
the radial arrangement of Its xylem and phloem it conforms 
to the normal type of tissue arrangement, nevertheless it may 
exhibit an anomaly which recalls that already described for 
the primary and first-formed lateral roots, namely, that the 
protoxylem of many or even all the rays do not abut im- 
mediately upon the endodermis (which is sharply marked 
from the first) but are separated from it by one or more layers 
