342 
Holden . — Observations on the 
one interesting point of similarity, this being the increase in the relative 
importance of the marginal strands in some of the specimens figured by 
Sterckx ( 15 ). Thus his Fig. 178 shows the marginal strands deferring their 
fusion with the median strand until well down the cotyledonary petiole, 
and Figs. 173 and j 76 illustrate cases in which the strands are apparently 
independent throughout the petiole. A similar increase in the relative 
importance of the lateral strands is also characteristic of many monocotyle- 
donous seedlings, although further complications are produced in many of 
these by the vascular system of the first epicotyledonary leaf contributing 
to that of the hypocotyl. Thus independent laterals characterize both 
Arum maculatum ( 14 ) and A. italicum ( 1 ), and Sargant ( 12 ) has described 
a number of species in the Scilleae (Liliaceae) in which all stages are shown, 
varying from a condition in which the contributions to the vascular sym- 
metry of the radicle by the cotyledonary lateral strands are more or less 
capricious (e.g. Galtonia candicans^Dipcadi serotinum) to forms in which the 
lateral bundles of the cotyledon take a perfectly regular share in the formation 
of the root stele. ‘ The species Hyacinthus romanus , Muscari atlanticum , 
M. armeniacum , and M. neglectum , for example, form a series in which the 
lateral traces become more and more important until they supply a full half 
of the root stele.’ 
Special mention must be made of the condition characterizing Anemar- 
rhena asphodeloides (10), in which extreme compression of the median and 
lateral bundles has resulted in their fusion to form two massive bundles 
situated one on either side of the sagittal plane of the seedling. The pro- 
toxylem of these bundles divides into three, the median portions each con- 
stituting a root pole situated in the intercotyledonary plane, whilst the 
others unite in pairs in the cotyledonary plane, so that a tetrarch root is 
formed. Sargant ( 12 ) regards the massive cotyledonary bundles as homo- 
logous with the 4 double bundle 5 characterizing the cotyledon of such forms 
as Allium , and there is little doubt that this is true, though of a portion 
only, of each of the Anemarrhena bundles. Chauveaud (1) has shown, 
however, that the widely separated halves of the double bundle of Allium 
originate as a radial file of protoxylem elements flanked by primary phloem, 
and that the wide separation of the two xylem segments in the maturer 
condition of the cotyledon is due to the successive resorption first of the 
radial file of vessels (Chauveaud’s ‘ vaisseaux alternes ’) and then of the 
intermediate vessels succeeding it on either side. The three stages are 
admirably illustrated in Chauveaud’s figures ( 1 , pp. 1 77-1 79, Figs. 20-25). 
A further point of interest in this connexion is provided by a comparison 
of Chauveaud’s Fig. 25, illustrating the last remnants of the crushed and 
partly resorbed intermediate vessels in Allium , with Sargant’s figure of 
a section across the cotyledon of Anemarrhena (10, PI. XXXIII, Fig. 2). 
The latter exhibits evidence for the resorption of intermediate vessels lying 
