Anatomy of Teratological Seedlings. III. 327 
of the cotyledonary laterals travelling round the outer ends of the bundles 
and uniting with that of the epicotyledonary laterals. At a slightly later 
stage the phloem, in some seedlings, forms locally a ring broken only 
opposite the median cotyledonary bundles. Simultaneously the epicotyle- 
donary and cotyledonary xylems are brought into close contact by a collar 
of transfusion tracheides extending across the inner faces of each of the 
latter. The identity of the epicotyledonary xylem is ultimately lost in the 
previously mentioned patch of secondary xylem. 
3. The atypical seedlings , with one exception, fall into two well-defined 
groups. The first of these comprises forty-three seedlings and forms a very 
complete series illustrating the development of a closely syncotylous condi- 
tion from the normal. 
Accompanying this development there has been a compression modifi- 
cation of the epicotyl, though the two processes have not proceeded with 
absolute uniformity. In all cases but one the syncotyly is essentially 
unilateral, although a short cotyledonary tube is very commonly formed. 
The exceptional specimen shows a fusion of the proximal third of the 
cotyledonary laminae and the distal parts of the petioles by their upper 
surfaces (Figs. 1 8 a, 18$). The resultant modifications in this instance have 
been relatively slight, consisting of a lateral displacement of the epicotyl and 
a distortion of one of the lateral cotyledonary bundles which is involved in 
the fusion and which appears to have lost its phloem locally. Of the 
remainder the simplest case is one in which the cotyledonary fusion is purely 
laminar (Fig. 12) although the petioles are closely apposed throughout. 
Both in this and in such cases as those in which the petioles only are com- 
pletely fused and in which the major portions of the laminae are free 
(Figs. 16 a, 1 6 b) the normal tetrarch symmetry of the vascular system 
remains undisturbed. In one seedling of this type, however, a curious 
condition is brought about by the persistence of the epicotyledonary xylem, 
which, lying in the intercotyledonary plane, constitutes a barrier between 
the apposed lateral bundles, preventing their fusion at the apex of the 
hypocotyl. The separation is maintained for quite a third of the way down 
the hypocotyl, and during that time the lateral bundles are endarch and 
offer a striking contrast to the exarch median bundles. Ultimately they 
unite, coming together at a very acute angle and thus differing from the 
sharp, almost horizontal fusion which is normal for the species. With 
regard to the modifications in the epicotyl, beyond a slight and variable 
reduction in the size of the leaf on the fusion side at the first node, these 
are usually negligible. One very definite tendency must, however, be noted, 
and that is that the vascular systems from the second epicotyledonary node 
incline to a precocious fusion with that of the reduced leaf, this often 
occurring prior to the entry into the stem of the vascular system of the 
unaffected leaf. As the laminae become more closely implicated in the 
