SEEDLING STRUCTURE IN THE LEGUMINOS#, 54 
The cortical fibrovaseular bundles of the epicotyl take their origin from the 
edges of the gap left in the ring of vascular tissue by the departing cotyledon 
bundles. 
We thus see that of the four primary xylem poles of the main root two 
supply the cotyledons, and two are direct prolongations of the vascular 
system of the first two epicotyledonary leaves (РІ. 8. fig. 106). 
(2) Seedlings with pentarch roots are very frequent, and the details of 
transition differ in some respects from those in the tetrarch cases. The five 
xylems are at first equidistant ; as we ascend the root where it dilates one of 
the xylems gradually dwindles, the protoxylem disappearing altogether, and 
the metaxylem becoming attached to the neighbouring xylem which is 
destined to supply one of the cotyledons. So that, so far as the xylem is 
concerned, the difference from the tetrarch type is not profound. The 
phloems, five in number, also suffer slightly different changes, which are best 
represented by a diagram (fig. 107). The difference trom the tet rarch type 
is simply the presence of two phloem bundles (one cotyledonary, one 
plumular) instead of a single bundle which later divides. 
Thus the pentarch type may be regarded as a tetrarch type with inter- 
calation of an extra xylem pole, arising from one of the cotyledonary bundles, 
and keeping distinet two of the phloem groups which in the tetrarch type 
fuse into a single group. 
(3) In a hexarch seedling the same process is repeated at both poles of the 
ellipse as occurs in one pole only of the pentarch type. Two supernumerary 
bundles are present, both on the same side of the stele, and as we ascend into 
the hypocotyl these fuse with their respective median cotyledonary bundles. 
The phloems are correspondingly modified (fig. 108). The condition of the 
vascular tissue at the cotyledonary node is essentially similar in tetrarch, 
pentareh, and hexarch types. 
The relation of the three types of. structures here described to one another 
is shown in figs. 106-108. (Cotyledonary xylem, cross-hatched ; phloem, 
dotted : plumular xylem, line-shaded ; phloem, clear: protoxylems which 
reach the cotyledonary node, black.) 
ABRUS PRECATORIUs, Linn. 
A much-branched climbing shrub. The seedling is very distinct in form 
from that of the other Viciew, and is rather comparable with certain Phaseoleve 
(e.g. Phaseolus radiatus). The hypocotyl is elongated; the cotyledons are thick 
and ovate, turning green in the light, with intercotyledonary fused stipules. 
The structure has been examined by Dangeard (1889, p. 111), who mentions 
shortly that “la tigele est longue [i. e. the transition is low] et les huit 
traces cotylédonnaires restent longtemps distinctes," following them down- 
wards; the root is tetrarch. My own examination of this species confirms 
these statements ; the following additional details may be given. 
