Seedling Anatomy of Certain Sympetalae . 731 
produced, in which the pith and endodermis are characteristic features 
(Diagram I, Fig. 6). 
Convolvulus tricolor , L. In this example, seedlings of which were 
obtained after the above description had been written, one or two differences 
must be noted. Externally the young plants are very similar, though in 
C. tricolor there is a tendency to form a slight cotyledonary tube. Inter- 
nally, also, the arrangements in this species and the var. major show a general 
similarity in the broad features. In the petiole anastomoses occur between 
the median bundle and the lateral ones, and often strands of phloem can be 
detected connecting the bundles together (Diagram 2, Fig. 1). In the 
upper part of the hypocotyl the two lateral bundles approach the median 
one, and finally more or less complete fusion occurs (Diagram 2, Figs. 2 
and 3). At a lower level the two lateral strands again separate, and, as in 
var. major , approach their fellows from the opposite cotyledons, giving rise 
to the intercotyledonary bundles of the tetrarch root (Diagram 2, Fig. 4, 
and Diagram 1, Figs. 6 and 7). 
Another difference consists in the presence, in the petiole and hypocotyl, 
of abundant internal phloem. This fact was noted by Lamounette ( 12 , 
p. 219), who, however, appears to have doubted the connexion between 
internal and external phloem traced by other observers (cf. Scott ( 18 ) and 
Scott and Brebner ( 19 )). In the upper part of the hypocotyl, during the 
rearrangements in the cotyledonary strand so that the protoxylem becomes 
external, the internal phloem masses of that bundle fuse, and the fused 
mass gradually passes out between the metaxylem groups (before the latter 
meet to form the root bundles) and joins on to the external phloem. 
The same events take place at a lower level in connexion with the 
intercotyledonary bundles, so that finally an ordinary tetrarch root is 
produced. 
Dangeard ( 5 ) investigated several examples belonging to the Convol- 
vulaceae, but in most cases only a general description of the genus is given. 
Among others, he described the following : 
Convolvulus , 
Calystegia , 
Quarnoclit coccinca , 
Ipomoea , 
all of which follow the method already given. One difference, however, 
must be noted. Speaking generally of the Convolvulaceae, Dangeard 
described the cotyledonary traces as being bicollateral in the hypocotyl. 
In the present research, however, nothing of the nature of internal phloem 
was found in any part of the seedling of C. tricolor , var. major. 
Ipomoea versicolor , Meissn. From the description by Scott ( 18 , 
