Seedling Anatomy of Certain Sympetalae . 741 
to rest near the periphery of the stele in the intercotyledonary plane, where 
each one fuses with its fellow from the other seed-leaf bundle (PI. LXVIII, 
Fig. 5). There are thus formed four protoxylem groups, of which the two in 
the cotyledonary plane are much the stronger, and in these the metaxylem 
closes in behind so that typical root bundles are produced. At a lower 
level metaxylem also appears on the inner side of the other protoxylem 
groups, and a tetrarch root results, in which the metaxylem always prepon- 
derates in the intracotyledonary strands (Diagram 7, Fig. 6). No other 
condition was found in any root. 
Diagram 7 . Incarvillea Delayvei. 
It is to be noted that the transition in this species is remarkably like 
that of A nemarrhena (13), in both of which a tetrarch root structure is ob- 
tained from two cotyledonary traces. This type of transition has hitherto 
been found, among dicotyledons, only in certain Cactaceae (6), and possibly 
in Eranthis and Podophyllum. 
Eccremocarpus scatter, Ruiz, et Pav. Only a single seedling of this 
species was available. This specimen was much smaller than those of 
Incarvillea Delayvei , and resembled the latter in no particular. The 
